Bones of upper limb 1

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CHAPTER 1
ILOs:
By the end of the lectures, the student should be able to:
 Recognize the name of each bone of the upper limb.
 Determine the site and side of each bone.
 Put the bones in their anatomical position.
 Describe the important features of each bone.
 Determine the growing end of each long bone.
 Locate the site of attachment of the related muscles and ligaments.
 Describe the carrying angle and its importance
 Interpret some clinical problems resulted from fracture of the bones
on anatomical basis of their relation to important structures.
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BONES OF UPPER LIMB

The bones of upper limb include:
1- Bones of the shoulder (pectoral) girdle (clavicle and scapula).
2- Bone of the arm: The humerus.
3- Bones of the forearm: Radius (laterally) and ulna (medially).
4- Bones of the hand: Carpal and metacarpal bones and phalanges.

SHOULDER (PECTORAL) GIRDLE

It is formed of right and left
halves (Fig. 1).
Each half is formed by the
clavicle (in front) and scapula
(on the back), articulating with
each other at the acromio-
clavicular joint.
In front, the two halves of the
shoulder girdle are connected
to each other by the upper end
of the sternum where the
medial ends of the clavicles
articulate with the sternum at
the sterno-clavicular joints.
Behind, the two scapulae are
widely separated from each
other being connected to the
axial skeleton only by muscles.
 Bones of upper limb 2
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I. CLAVICLE
- Site: it is the anterior bone of the shoulder girdle. It lies horizontally at the
root of neck. It is subcutaneous throughout its whole lenghth extending
from the sternum medially to the shoulder laterally.
- Type: it is a long bone. Unlike other long bones, the clavicle differs in the
following:
1. Its lateral one third has no medullary cavity, where it consists of a
mass of spongy bone covered by a layer of compact bone.
2. It is formed by membranous ossification; therefore it is the first long
bone to ossify in the embryo.
3. It is the only long bone placed horizontally.
- General Features (Figs. 2,3): It has a shaft and two ends (medial and
lateral)
A. Ends:
1. Lateral (acromial) end: it is flattened and presents a small oval
articular facet to articulate with the medial side of acromion at the
acromio-clavicular joint.
2. Medial (sternal) end: it is enlarged (prismatic) and Presents a
smooth triangular articular surface to articulate with the clavicular notch of
manubrium sterni and the 1st costal cartilage
B. Shaft:
It is S-shaped with the lateral one third Convex backwards to meet the
scapula and medial two thirds convex forwards to give passage for large
vessels and nerves between neck and axilla.
1. The lateral 1/3 of the shaft has the following features:
 It is falttened from above downward.
 It has no medullary vavity.
 Its anterior border may present a small tubercle called deltoid
tubercle.
 Its Lower surface shows:
a. Conoid tubercle: is lying close to the posterior border at junction
of lateral third with medial two thirds of clavicle.
b. Trapezoid ridge: Extends forwards and laterally from the conoid
tubercle towards the acromial end.
2. The medial 2/3 of the shaft has the following features:
 It is cylindrical in cross section.
 It has medullary cavity.
 Its lower surface has the following features:
a. A rough impression near the sternal end that gives attachment to
the costo-clavicular ligament.
b. A longitudinal groove in the intermediate third of the bone for
insertion of the subclavius muscle.
c. A nutrient foramen, commonly directed laterally, lying close to the
groove for subclavius.
 Bones of upper limb 3
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Fig. 2:
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Fig. 3:

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 Bones of upper limb 4
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II. SCAPULA
- Site: it is the posterior bone of the shoulder girdle. It lies in an oblique
plane on the postero-lateral aspect of the chest wall covering posterior
parts of the 2nd to the 7th ribs.
- Type: flat bone.
- General Features (Figs. 4,5): it is a large flattened triangular bone
having:
A. Two surfaces. B. Three borders.
C. Three angles. D. Three processes.
A. Surfaces
1. Anterior Surface (ventral or costal surface):
 It is directed forwards and medially, because of the oblique plane of
the scapula.
 It is slightly concave and forms the subscapular fossa.
 It shows three or four ridges for the origin of subscapularis muscle.
2. Posterior Surface (dorsal Surface):
 Directed backwards and laterally.
 Slightly convex.
 Divided by a triangular horizontal shelf-like projection, termed the
spine of scapula, into:
a. A smaller upper area which, together with the upper surface of the
spine, forms the small supraspinous fossa.
b. A larger lower area which, together with the lower surface of the
spine, forms the larger infraspinous fossa.
B. Borders
1. Lateral Border:
 It is thick rough border.
 At its upper end, it shows a rough triangular area called infra-
glenoid tubercle
 Which lies just below the glenoid cavity.
 Its dorsal aspect shows a flattened strip for muscular attachment.
 Being near the axilla, it is called axillary border.
2. Medial Border
 It is thin and the longest border.
 At the root of the spine of scapula, it forms an obtuse angle.
 In the normal anatomical position, it runs nearly vertical parallel to
and about 5 cm. from the spinous processes of the vertebrae.
Therefore, it is called vertebral border.
3. Superior Border
 It is thin, sharp and the shortest border.
 Near its lateral end, it shows a small supra-scapular notch
 Just lateral to the supra-scapular notch, the coracoid process projects
upwards by a thick root.
 Bones of upper limb 5
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Fig. 4: Scapula
Anterior (ventral) surface
 Bones of upper limb 6
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C. Angles
1. Inferior angle
It is an acute angle and lies over the 7th rib or 7th intercostal space.
2. Superior angle
It is nearly a right angle and lies over the 2nd rib.
3. Lateral angle
 It is broadened and may be regarded as the head of scapula and is
connected to the flat body by a slightly constricted neck.
 On its free surface, it carries the glenoid cavity for articulation with the
head of the humerus (the socket of the shoulder joint). The glenoid
cavity has the following features:
a. It is pear-shaped (narrow above and wider below) with prominent
margins. It is shallow concave forming a poor socket for the head
of the humerus.
b. It is completely smooth and is covered by a layer of hyaline
articular cartilage.
c. It is directed laterally and slightly forwards and upwards.
 Immediately above the glenoid cavity, there is a small supra-glenoid
tubercle which encroaches on the root of the coracoid process.

D. Processes
1. Spine of Scapula
 It is a horizontal shelf-like process projecting backwards from the upper
part of dorsal surface.
 It is triangular in shape having:
1. Two surfaces; upper and lower
2. Two free borders, Posterior and lateral:
- The posterior free border: is called crest of the spine and is felt
subcutaneously, it has the following features:
a. It has upper and lower margins (lips) and an intermediate surface
(in-between) which shows a rough prominence near its medial end
(root of spine).
b. At its lateral end, the crest bends and turns upwards and forwards
to form the acromion process.
- The lateral free border is thick and curved to bound a notch called
spino-glenoid notch lying between it and the posterior aspect of
the neck of the scapula through which the supra-spinous and infra-
spinous fossae communicate.
 Bones of upper limb 7
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Fig. 5: Scapula
Posterior (dorsal) surface
 Bones of upper limb 8
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2. Acromion Process:
 It is a rectangular process which projects upwards and forwards as a
continuation of the lateral end of the crest of the spine.
 Its medial border carries a small oval facet to articulate with lateral
end of the clavicle at the acromio-clavicular joint.
 Its lateral border is continuous with the spine at the acromial angle.
3. Coracoid Process:
 It arises by a broad root from the lateral end of the superior border
of scapula just lateral to supra-scapular notch and bends forwards
and slightly laterally.
 The process has an enlarged tip with upper and lower surfaces and
medial and lateral borders.

BONE OF THE ARM

HUMERUS

- Site: it is the bone of the arm.

- Type: long bone.
- General Features (Figs.6,7): it consists of expanded upper and lower
ends and a shaft.
A. Upper End:
1. Head (the ball of the shoulder joint):
 It is less than half of a large sphere.
 It is completely smooth and covered with hyaline cartilage.
 It is directed upwards, backwards and medially to articulate with the
glenoid cavity.
 Its articular surface is about four times the area of the glenoid cavity.
At rest its anterior-inferior quadrant articulates with the glenoid cavity
allowing a wide range of lateral rotation and abduction from this
position.

2. Anatomical Neck:
 It is a faint constriction immediately adjoining the margin of the head.
 It is relatively thick.
N.B. The upper end of the humerus joins the shaft at the surgical neck which is
more constricted than the anatomical neck and is the commonest site of
fracture. The surgical neck represents the upper end of the shaft.

3. Lesser Tuberosity (Tubercle):

 It projects forwards immediately below the anatomical neck.
 It continues downwards as the medial lip of bicipital groove.
 Bones of upper limb 9
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

Fig. 6: Humerus Fig. 7: Humerus

Posterior view Anterior view
 Bones of upper limb 10
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4. Greater Tuberosity (Tubercle):
 It occupies the lateral part of the upper end of the humerus.
 Its anterior margin continues downwards as the lateral lip of
bicipital groove.
 Its upper and posterior aspect shows three flattened impressions
for muscular attachment.
N.B.:
The two tuberosities are separated from each other on the anterior aspect by a
groove called the intertubercular or bicipital groove. The bicipital groove
extends downwards into the front of the upper part of the shaft where it has
lateral and medial lips with a floor in between.

B. Lower End:
It is expanded transversely and presents articular and non-articular portions.

1. Articular portion: (the condyle; conjoined capitulum and trochea). It is

divided by a faint groove into capitulum (laterally) and trochlea (medially)
to articulate with radius and ulna forming the elbow joint.

a. Capitulum
 It is a smooth, rounded convex projection (less than half of a
sphere).
 It articulates with the upper surface of the head of radius.

b. Trochlea
 It is a smooth pulley-shaped surface, slightly constricted near its
middle.
 It articulates with the trochlear notch of the ulna.

2. Non-articular portion: includes the medial and lateral epicondyles and

the olecranon, coronoid and radial fossae.

a. Medial epicondyle:
 It is a large blunt projection, more prominent than the lateral
epicondyle.
 It can be easily felt subcutaneously.
 Its anterior surface is rough as it gives muscle attachment.

b. Lateral epicondyle:
 It is a less marked projection.
 Its anterior and lateral surfaces show a rough impression for
attachment of muscles.

c. Olecranon fossa:
 It is a deep hollow on the posterior surface above the trochlea. Its
floor is thin and may be deficient (perforated).
 Bones of upper limb 11
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 It receives the tip of the olecranon process of ulna when the elbow
is fully extended.

d. Coronoid fossa:
 It is a smaller hollow on the anterior surface above the trochlea.
 It receives the tip of the coronoid process of ulna when the elbow is
fully flexed.

e. Radial fossa:
 It is a very shallow depression lying on the anterior surface above
the capitulum (lateral to the coronoid fossa).
 It receives the margin of head of radius in full flexion of the elbow.

C. The Shaft
It is nearly cylindrical in its upper half and triangular in section in its lower
half. It presents 3 surfaces and 3 borders.

1. Three Borders:
a. Anterior border (from below upwards):
 It is smooth and rounded in the lower half of the shaft.
 In the middle part, it forms the anterior limb of deltoid tuberosity.
 In the upper part, it becomes continuous with the lateral lip of
bicipital groove.
b. Medial border:
 It is clear in the lower half of the shaft.
 Its lower part becomes sharp and is called medial supra-condylar
ridge. It terminates below at the medial epicondyle.
 At the middle of the shaft, it presents a rough area for muscular
attachment (insertion of coraco-brachialis).
c. Lateral border:
 It is clear in the lower half of the shaft where it is roughened along
its anterior aspect for muscular attachment.
 Its lower part becomes sharp and is called lateral supra-condylar
ridge. It terminates below at the lateral epicondyle.
 About the middle of the shaft, it is interrupted by the radial or
spiral groove turning downwards and forwards from the posterior
surface to the anterior surface of the shaft.

2. Three Surfaces:

a. Antero-medial surface:
 It is smooth
 A little below its middle, it shows a nutrient foramen which is
directed downwards.
 Bones of upper limb 12
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b. Anterolateral surface:
 At its middle, it is marked by a V-shaped rough area which is called
deltoid tuberosity (deltoid insertion).
 Its anterior limb is continuous with the anterior border of the shaft
while its posterior limb bounds the radial groove.

c. Posterior surface:
 Its upper third is crossed by a faint ridge for origin of the lateral
head of the triceps muscle.
 Its middle third is crossed by a wide, shallow groove (radial or spiral
groove) which passes downwards and laterally, then turns forwards
to reach the antero-lateral surface where it fades away.

The Carrying angle

The medial margin of the trochlea projects downwards more than the
lateral margin producing an angle between the long axis of the humerus
and the long axis of the supinated forearm when the elbow is fully
extended (Fig.8). This angle is about 15 degrees and is more marked in
females.

Clinical importance:
It allows the forearm to swing clear from the pelvis especially in the female
who has a wider pelvis. This angle disappears when the forearm is
pronated or the elbow is flexed.
 Bones of upper limb 13
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Fig. 8: Carrying angle

 Bones of upper limb 14
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BONES OF THE FOREARM

I- RADIUS

- Site: it is the lateral bone of the forearm.

- Type: it is a long bone.
- General Features (Figs. 9, 10, 11, 12): it has a shaft, upper and lower
expanded ends but the lower end is much expanded than the upper end.

A. Upper End
1. Head
 It is disc shaped.
 It has two smooth articular surfaces:
1. Upper circular concave articular surface which articulates with the
capitulum of the humerus to form part of the elbow joint.
2. Its circumference, which is smooth and broader medially,
articulates with radial notch of ulna to form superior radio-ulnar
joint.

2. Neck: is the constricted part below the head.

3. Radial Tuberosity: projects antero-medially below the neck. Its

anterior part is smooth while its posterior part is rough.

B. Lower End:
It is a flattened expanded end having five surfaces:
1. Anterior surface: smooth and slightly concave.
2. Posterior surface: is rough and convex:
 Near its middle, it shows a very prominent ridge called dorsal tubercle
(of Lister) which forms the lateral boundary of a narrow deep oblique
groove.
 On its lateral part, (lateral to the tubercle) it shows a wide shallow
groove which is divided into two parts by a faint vertical ridge.
 On its medial part, it shows a wide shallow groove.
3. Lateral surface: is rough and projects downwards to form a pyramidal
styloid process.
4. Medial surface: shows a concave articular surface called ulnar notch of
radius which articulates with the head of ulna to form inferior radio-ulnar
joint.
5. Inferior (carpal) surface: is concave articular surface, which shares in
the wrist joint and is divided by a slight constriction into:
A. A medial quadrilateral area articulates with the lunate bone.
B. A lateral triangular area articulates with the scaphoid bone.
 Bones of upper limb 15
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
Fig. 9: Ulna & radius (Anterior view)
 Bones of upper limb 16
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C. Shaft:
 It increases gradually in thickness as followed downwards.
 It is gently curved being convex laterally.
 It is triangular in section having three borders and three surfaces:

a. Borders:
1. Interosseous (medial) border:
Above, it begins below the radial tuberosity and Its middle part is
prominent.
2. Anterior border:
Above, it begins from radial tuberosity and runs obliquely downwards and
laterally; this part is called anterior oblique line.
3. Posterior border:
Above, it begins from the posterior part of radial tuberosity and runs
obliquely downwards and laterally (similar to the anterior oblique line) and
is called posterior oblique line.

b. Surfaces:
1. Anterior surface
It is slightly concave. It presents a nutrient foramen, which is directed
upwards.
2. Posterior surface:
It is generally flat and featureless.
3. Lateral surface:
It is convex presents a rough impression (pronator tuberosity) at it
middle for insertion of the pronator teres muscle.

Ulna Radius

Fig. 10: Lower end of radius

(Posterior view)
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 Bones of upper limb 17
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Fig. 11: Ulna & radius (Posterior view)

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 Bones of upper limb 18
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II- ULNA
- Site: it is the medial bone of the forearm and is parallel to the radius when
the forearm is supinated (the normal anatomical position).
- Type: long bone
- General Features (Figs. 9, 11, 12, 13): the ulna has a shaft, upper and
lower ends. Unlike the radius, its upper end is markedly expanded:

A. Upper End
1. Olecranon process:
 It forms the uppermost part of the bone. Its upper part bends
forwards to form a prominent tip which projects into olecranon fossa
of humerus when the elbow is fully extended.
 Its posterior surface is smooth, subcutaneous and triangular in outline
with its apex directed downwards to be continuous with the posterior
border of the shaft.
 Its anterior surface is smooth, articular and forms the upper part of
the trochlear notch.
 Its upper surface (top) is rough in its posterior part.

2. Coronoid process:
 It projects forwards from the upper end of the shaft and its anterior tip
projects into the coronoid fossa of the humerus when the elbow is
fully flexed.
 Its upper surface is smooth and articular forming the lower part of the
trochlear notch.
 Its anterior surface, below its tip, shows a rough tuberosity (ulnar
tuberosity).
 Its medial border is sharp.
 Its lateral surface shows the smooth radial notch for articulation with
the circumference of the head of radius forming superior radio-
ulnar joint. Below the radial notch, there is a fossa called
supinator fossa which makes room for the rotating radial tuberosity
during pronation. The fossa is bounded posteriorly by a prominent
ridge called supinator crest, which is continuous below with the
interosseous border of the shaft.

3. Trochlear notch:
 It is a deeply concave articular surface which articulates with the
trochlea of humerus to form part of elbow joint.
 It is formed by the anterior surface of olecranon and upper surface of
coronoid process. The bone is constricted at the junction between
these two areas.
 The articular surface of the notch shows a smooth vertical ridge, which
fits into the groove of the trochlea of the humerus.
 Bones of upper limb 19
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Fig. 12: Inferior surface of ulna & radius

 Bones of upper limb 20
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B. Lower End
It is slightly expanded and formed of head and styloid process.
1. Head:
 It is rounded presenting a convex articular surface on its lateral side
for articulation with ulnar notch of radius to form inferior radio-
ulnar joint.
 Its inferior surface is smooth and is separated from the base of the
styloid process by a rough impression. This rough impression gives
attachment to the apex of a triangular articular disc of cartilage which
lies below the head of ulna separating it (above) from the triquetral
carpal bone (below).

2. Styloid process: a short rounded projection (shorter than that of

radius) which projects from the postero-medial aspect of the lower end
of ulna. A groove is seen on the back between the head and the styloid
process.

C. The Shaft
It is triangular, on cross-section, in its upper three quarters and is nearly
cylindrical in its lower quarter. It has three surfaces and three borders:
a. Borders:
1. Interosseous (lateral) border: above, it is continuous with the
supinator crest.

2. Anterior border: it begins, above, at the medial side of ulnar

tuberosity.

3. Posterior border: it begins, above, as a downward continuation of

the apex of the triangular surface on the back of the olecranon.

b. Surfaces

1. Anterior surface: is slightly concave from side to side. Near its

middle it presents a nutrient foramen which is directed upwards.

2. Medial surface: is slightly convex from front backwards. It is

smooth and featureless.

3. Posterior surface: it presents the following features:

 A faint oblique ridge in its upper third.
 A vertical ridge in its lower two thirds which divides the posterior
surface into two areas (medial and lateral) for muscular attachment.
 Bones of upper limb 21
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BONES OF THE HAND

They are divided into three regions (Figs. 14, 15, 16):
1. Wrist (Carpus) bones (eight carpal bones).
2. Palm bones (five metacarpal bones).
3. Finger bones (fourteen phalanges).

I. Carpal bones: are eight in number and arranged in two rows:

A. Proximal row: four bones from lateral to medial: Scaphoid, lunate,
triquetral and pisiform.
1. Scaphoid Bone: is the largest bone of the proximal row and it is a
boat-like, hence its name. The scaphoid has a tubercle on its
anterior aspect which gives attachment to the flexor retinaulcum.

N.B.: It is the commonest carpal bone to be fractured, after falling on

the outstretched hand.
Unfortunately the healing is poor or delayed in many cases because the
bone usually receives blood vessels through its distal part only. In such
cases, a fracture at the middle of the scaphoid deprives the proximal
fragment of its arterial supply and the fragment undergoes avascular
necrosis.

2. Lunate Bone: crescentic or semilunar in shape, hence its name

and it is broader on the anterior than the posterior aspect.

N.B.: Anterior dislocation of the lunate is common as a result of wrist

injuries.

3. Triquetral Bone: a three sided pyramid, hence its name.

4. Pisiform Bone: the smallest of the carpal bones. It is spheroidal

in form and is situated on a plane anterior to the triquetral, adding
to the anterior concavity of the carpal arch. It is a sesamoid bone
present in the tendon of flexor carpi ulnaris and is the last carpal
bone to ossify. It gives attachment to both flexor and extensor
retinacula.
B. Distal row: four bones from lateral to medial: Trapezium, trapezoid,
capitate and hamate.
1. The trapezium has a distal saddle-shaped facet for the base of
the first metacarpal forming together the famous saddle joint
(carpometacarpal joint of the thumb). Its anterior aspect shows a
groove for the tendon of flexor carpi radialis. The lateral edge of
the groove is prominent forming a crest (crest of trapezium).
Lateral end of the flexor retinaculum split into two laminae to
become attached to both edges of the groove of trapezium.
 Bones of upper limb 22
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2. The trapezoid is smaller than trapezium and articulates with the
base of the second metacarpal bone of the index.
3. The capitate is the largest of the carpal bones and the first to
ossify. It articulates with the base of the third metacarpal bone. It
has a prominent head on its distal end.
4. The hamate sends a marked hook anteriorly, which gives
attachment to the flexor retinaculum. It articulates with the bases
of the fourth and fifth metacarpal bones.
N.B.
1. The anterior aspect of the carpus is concave and is called the carpal arch.
The carpal arch is bridged over by the flexor retinaculum converting it into the carpal
canal or tunnel for passage of the flexor tendons, their synovial sheathes and the
median nerve.
2. Each carpal bone usually ossifies from one center postnatally. Those for the capitate
and hamate develop first and may appear before birth.
Radiography of the carpus is frequently used for the assessment of skeletal maturation.

Pisiform is seen only

in the anterior view

Fig. 14: Carpal bones

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 Bones of upper limb 23
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Fig. 15: Bones of the hand (anterior view)

Fig. 16: Bones of the hand (Posterior view)

 Bones of upper limb 24
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II. The Metacarpal Bones: are five bones numbered from one to five,
fromthe thumb to the little finger. The first is the shortest and the second the
longest. Their posterior aspects can be felt under cover of the extensor tendons.
Each metacarpal is a long bone, consisting of a base proximally, a shaft and a
head distally.
A. The base of each metacarpal articulates with the distal row of carpal
bones to form a carpo-metacarpal joint as well as with the bases of the
adjacent metacarpals. The base of the first metacarpal bone articulates
with the trapezium and has a separate joint cavity which is not
continuous withother carpometacarpal joint.
B. The shaft: as any long bone but on a narrow scale.
C. The head of each metacarpal articulates with the base of the proximal
phalanx of the corresponding finger and forms a knuckle of the closed
fist of the hand.
II. The Phalanges:
The thumb has two phalanges (proximal and distal) while each of the
other fingers has three phalanges (proximal, middle and distal).
Each phalanx is a long bone, consisting of a base proximally; a shaft
and a head distally.
The base of each proximal phalanx articulates with the head of the
corresponding metacarpal at the metacarpophalangeal joint while its
head presents two condyles for the base of a middle phalanx forming
the proximal interphalangeal joint.
Similarly, the head of each middle phalanx presents two condyles for
the base of a distal phalanx forming the distal interphalangeal joints.

N.B.
*In case of the thumb, the proximal phalanx articulates directly with
the distal phalanx forming only one interphalangeal joint.

*Sesamoid bones are found to be related to the anterior aspects of

some of the metacarpo-phalangeal and interphalangeal joints.
*Two seasamoid bones, located anterior to the head of the first
metacarpal, are almost constant.
 Bones of upper limb 25
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MUSCLES AND LIGAMENTS ATTACHED TO THE BONES

I- Muscles and ligaments attached to the clavicle:

The attachments of these structures will be fully described later (Fig.17-a & b).

Fig. 17-a: Upper surface of right clavicle

Capsule of
acromioclavicular Trapezius (i)
joint
Sternomastoid (o)

Acromial Sternal
end end
Deltoid (o) Capsule of
sternoclavicular
Pectoralis major (o) joint

Capsule of
acromioclavicular
joint Pectoralis major (o)
Deltoid (o)

Acromial
end

Sternal end
Subclavius (i)
Trapezius (i)
Capsule of
Costo-
Coracoclavicular sternoclavicular
clavicular
ligament ligament joint

Fig. 17-b: Lower surface of right clavicle (o): origin

( i ): insertion
 Bones of upper limb 26

II- Muscles and ligaments attached to the scapula:
The attachments of these structures will be fully described later (Figs.
18,19).

(o): origin
( i ): insertion Fig. 18: Ventral surface of scapula


(o): origin 
Fig.19: Dorsal surface of scapula ( i ): insertion

 Bones of upper limb 27

III- Muscles and ligaments attached to the humerus:
The attachments of these structures will be fully described later(Figs. 20, 21)

Fig. 20: Anterior surface of right humerus


(o): origin
( i ): insertion Fig. 21: Posterior surface of right humerus

 Bones of upper limb 28

IV- Muscles and ligaments attached to the ulna and
radius:
The attachments of these structures will be fully described later (Figs. 22,
23).

(o): origin
( i ): insertion


joint

Fig. 22: Anterior surface of right Fig. 23: Posterior surface of right
ulna & radius ulna & radius
 Bones of upper limb 29

V- Muscles and ligaments attached to the hand bones:
The attachments of these structures will be fully described later (Figs. 24, 25)

(o): origin
( i ): insertion



Fig. 24: Palmer surface of the hand


(o): origin
( i ): insertion Fig. 25: Dorsal surface of the hand

 Bones of upper limb 30

Subcutaneous parts of the bones of upper limb

 Clavicle Medial end – lateral end - shaft

 Scapula Acromion process
Coracoid process
Crest of the spine of the scapula
Medial border
Inferior angle
 Humerus Lesser tubercle
Greater tubercle
Medial epicondyle
Lateral epicondyle
 Ulna Olecranon process
Posterior border
Head of ulna
Styloid process of ulna
 Radius Head of radius
Styloid process of radius
 Carpal bones Pisiform
Hook of hamate
Scaphoid
 Metacarpal bones Heads of metacarpal bones(knuckles)

Formative assessment
I. Give an explanation for each of the following:
a. The carrying angle in female is larger than that in male.
b. A fracture at the middle of the scaphoid bone may result in
avascular necrosis (death) of its proximal fragment.
II.M.C.Q:
1- Which of the following bones is a flat bone:
a. Humerus
b. Scapula
c. Ulna
d. clavicle
2- One of the following bones undergoes membranous ossification:
a. Clavicle
b. Radius
c. Humerus
d. Ulna
 Pectoral region 31

CHAPTER 2

ILOs:
By the end of the lectures, the student should be able to:
 Identify the clavipectoral fascia.
 Describe the attachments, structures piercing & structures deep to the
clavipectoral fascia.
 Enumerate the muscles of the pectoral region.
 Enumerate muscles connecting the upper limb with the thoracic wall
 Discuss the attachments, nerve supply & actions of muscles
connecting the upper limb with the thoracic wall.
 Interpret some clinical problem of serratus anterior on the anatomical
basis.
 Define shape, position & type of the mammary gland
 Describe the structure& arterial supply of the mammary gland
 Explain the lymph nodes which are involved in carcinoma of the breast
 Interpret some clinical problem related to the internal structure of the
breast & lymphatic drainage.

PECTORAL REGION

It is the region on the upper part of the front of the chest wall down to the 6 th
rib. It includes:
1- Skin.
2- Superficial fascia which contains the mammary gland.
3- Deep (pectoral) fascia.
4- Muscles.

Cutaneous Nerves of the Pectoral Region

1- Supraclavicular nerves (C.3,4): they are branches from the cervical plexus
in the neck (medial, intermediate and lateral supraclavicular nerves). They
supply the skin covering the area between the clavicle and 2nd rib
including the skin covering upper 1/2 of Deltoid muscle.
N.B.:
The lateral supraclavicular nerve (C.4) supplies the skin of the upper part of the
shoulder region.

2- Anterior and lateral cutaneous branches of intercostal nerves (from T2 to

T6): they supply the skin covering the area below the 2nd rib.
 Pectoral region 32

The Mammary Gland
- Shape and type (Fig. 26): it is a modified sweat gland (rudimentary in
male), hemispherical in shape and the covering skin contains the nipple
and areola. It has a circular base and an axillary tail.
- Position (Figs. 26, 27):
 It lies in the superficial fascia of the pectoral region at the front and side
of the thorax.
 The base of the mammary gland extends from the 2nd rib above to the 6th
costal cartilage below and from the lateral border of the sternum medially
to the mid-axillary line laterally.
 Its base lies on the deep fascia covering the pectoralis major (pectoral
fascia) and serratus anterior muscles as well as the aponeurosis of the
external oblique muscle and the upper part of the rectus sheath of the
anterior abdominal wall.
 The axillary tail. it is a tongue-like prolongation from the superolateral
quadrant of the gland which curves around the lower border of pectoralis
major muscle, pierces the deep axillary fascia and extends upwards into
the axilla to lie close to the axillary artery and in direct contact with the
pectoral group of axillary lymph node.
N.B. The mid-axillary line is a vertical line passing in the midline of the axilla midway
beween its anterior and posterior fold.
- Structure:
A- Internal structure (Figs. 28, 29):
 The mammary gland consists of 16-20 lobes embedded in the fat of the
superficial fascia and arranged in a radial manner converging towards the
nipple.
 The lobes are supported and separated into fascial compartments by
fibrous septa called Cooper’s ligaments extending from the skin to the
deep fascia on the chest wall and suspending the breast to the skin. In
cancer breast, if the malignant tumour involves these fibrous septa it
may pull on the overlying skin leading to its dimpling; and obstructs the
skin lymphatics a condition called peau d'orange.
 Breast abscess should be drained by a radial incision to avoid spread of
infection to the neighbouring lobes and to minimize the damage of the
radially arranged ducts.
 Each lobe collects its secretion into a lactiferous duct. All lactiferous ducts
converge upon the nipple. As it passes deep to the areola, each lactiferous
duct widens to form a lactiferous sinus and then becomes narrow again
traversing the nipple to open on its summit.
N.B. The gland is small in children. It enlarges in young females at puberty due to
increase in the amount of superficial fascia and fat (stroma). The second
enlargement occurs during the first pregnancy as result of proliferation of the
glandular tissue and the gland reaches its maximum size during lactation.
 Pectoral region 33


Pectoralis major
2nd rib

Sternum

6th rib
Breast tail
Rectus sheath

External oblique muscle

& aponeurosis

Serratus
anterior Fig. 26: Mammary gland: extent
 & underlying structures

Fig. 27: Quadrants of the breast and the tail

 Pectoral region 34

B- Covering skin (Nipple and Areola) (Fig. 28):
 The nipple is a conical projection placed usually over the 4th intercostals
space and is traversed by the lactiferous ducts which open on its summit.
The position of the nipple changes after the 1st childbirth and lactation
where it lies at a variable lower level.
 The areola is a circular area of pigmented skin which surrounds the base of
the nipple. In virgins the areola is pinkish and becomes darker in color
during the first pregnancy and never returns pinkish again. It contains a
number of sebaceous (areolar) glands.

- Arterial supply (Fig. 30):

1. Lateral thoracic artery: from the 2nd part of the axillary artery,
supplies mainly the lateral half of the breast.
2. Perforating branches of the internal mammary artery,
especially in the 2nd, 3rd & 4th intercostal spaces, supply mainly the
medial half of the breast.
3. Lateral branches of the posterior intercostal arteries (are a
minimal source) share in supplying the lateral half.
4. Pectoral branch of acromiothoracic artery of the second
part of Axillary artery.

- Lymphatic drainage (Fig. 31): the lymphatics of the breast are arranged
as two plexuses:
A. Superficial (subareolar) plexus: it lies under the skin of the areola:
It receives afferents from the mammary gland and sends its efferents
to the deep lymphatic plexus, through interlobular lymph vessels.
B. Deep lymphatic plexus: it lies on the deep fascia on which the
mammary gland lies. It receives its afferents from the four quadrants
of the mammary gland and the superficial plexus. It sends its efferents
along the blood supply as follows:
1. Lateral quadrants: send efferents:
 Mainly to the pectoral group of axillary lymph nodes.
 From the tail to the subscapular group of axillary lymph nodes.
 From the upper lateral part to the infra-clavicular nodes (a
superficial group lying outside the axilla). Its efferents pierce
the anterior wall of the axilla to drain finally into apical group of
axillary lymph nodes.
N.B. Few lymphatics from the lateral part follow the posterior intercostals
arteries backwards to reach the para-aortic (posterior mediastinal)
lymph nodes inside the thorax.
 Pectoral region 35

 Pectoral region 36

2. Medial quadrants: send efferents:
 Mainly to the parasternal lymph nodes which lie along the
internal mammary artery inside the thorax.
 Some lymphatics cross the middle line to the deep plexus of the
opposite side.
 Some lymphatics from the lower medial part pierce the
abdominal wall to reach the subdiaphragmatic plexus and lymph
nodes in the rectus sheath.

N.B. The axillary lymph nodes commonly receive more than 75% of the
lymph from the breast while most of the reminder, from the medial and
lateral halves of the gland, enters the the parasternal nodes.

Clinical importance:
 In cancer breast:
*If the malignant tumor invades the fibrous septa and may pull on the
overlying skin leading to its dimpling and retraction of the nipple.
*Obstruction of the superficial lymphatics caused oedema of the skin which is
pitted by the attachments of the hair follicles and the skin appears as an
orange peel a condition called peau d'orange.
 Breast abscess should be drained by a radial incision to avoid spread of
infection to the neighboring lobes and to minimize the damage of the radially
arranged ducts.
 Pectoral region 37


Fig. 30: Mammary gland (arterial supply)

Cephalic vein

S: Supraclavicular LN

I: Apical group &

infraclavicular LN

C: Central group of LN

L: Lateral group of LN
Axillary vein
A: Anterior group of
LN

P: Posterior group of
LN

PS: Parasternal LN

R: Plexus of
lymphatics on rectus
sheath and subphrenic
plexus
R

Fig. 31: Lymphatic drainage of the breast
 Pectoral region 38

The Pectoral fascia
This is the deep fascia of the pectoral region. It covers the pectoralis major
muscle beneath the breast and has the following extensions:

1. Axillary fascia which forms the floor of the axilla.

2. Clavipectoral fascia.

Clavi-Pectoral Fascia
- Site (Fig. 32): it is a strong fibrous sheet of deep fascia, which occupies
the interval between the subclavius muscle above and pectoralis minor
muscle below. It lies behind the upper part of pectoralis major. It covers
the axillary vessels and nerves.

- Attachment (Figs. 32, 33, 34):

 Above: it splits to enclose the subclavius muscle and becomes
attached to the margins of the groove of subclavius on the lower
surface of the clavicle.
 Medially: it is thickened and extends to the 1st and 2nd costal
cartilages.
 Laterally: it extends to the coracoid process where it blends with
coraco-clavicular ligament.
 Below: it splits to enclose pectoralis minor. From the lower border of
this muscle it continues downwards as suspensory ligament of the
axilla to join the axillary fascia (in the floor of the axilla).

- Structures piercing the fascia (Fig. 32):

1. Cephalic vein.
2. Lateral pectoral nerve.
3. Acromio-thoracic artery.
4. Lymph vessels from infra-clavicular lymph nodes (outside the axilla)
draining into apical group of axillary lymph nodes.
- Structures deep to the fascia:
1. First part of the axillary artery.
2. Axillary vein.
3. Cords of brachial plexus.
4. Apical lymph nodes.
 Pectoral region 39

Subclavius muscle
Deltoid muscle

Cephalic vein

Acromiothoracic
artery

Lateral pectoral
nerve

Pectoralis minor
muscle

Pectoralis major
muscle (cut)

Attachment of
fascia to floor of
axilla

Fig. 32: Pectoral region showing

clavipectroral fascia




Fig. 33: A diagram showing the extent  Fig. 34: A diagram of a longitudinal
of the clavipectoral fascia section in the pectoral region showing
 parts of clavipectoral fascia
 Pectoral region 40

MUSCLES OF PECTORAL REGION
I- Pectoralis major muscle (Fig.35):
It is the superficial muscle of the pectoral region which extends laterally to
form the anterior wall of the axilla.
- Origin:
It arises by 2 heads:
1. Clavicular head: arises from the anterior surface of the medial ½ of
the clavicle.
2. Sternocostal head: it is larger and it arises from :
. Half of the anterior surface of the sternum down to the xiphi-
sternal junction.
. Front of the upper 6 costal cartilages.
. External oblique aponeurosis.
- Insertion:
It is inserted by a bilaminar tendon into the lateral lip of the intertubercular
(bicipital) groove as follow:
The anterior lamina is formed by the clavicular head and its inserted lower
down, while the posterior lamina is formed by the sternocostal head and it is
inserted into the upper part of the lateral lip.
The two laminae are continuous together from below forming a U-shaped
arrangement. This twisting of the lower border of the tendon forms the
anterior axillary fold.
- Nerve supply: Lateral and medial pectoral nerves.
- Action:
 As a whole, the muscle adducts and medially rotates the arm.
 The clavicular head flexes the arm.
 The strenocostal head extends the flexed arm and comes to work in
swimming, rowing and climbing.

II- Pectoralis minor (Fig. 35):

It is a triangular muscle situated deep to the middle part of the pectoralis
major.
- Origin:
From the outer surfaces of the 3rd,4th and 5th ribs near their costal
cartilages.
- Insertion:
Into the medial border and the upper surface of the coracoid process.
- Nerve supply: Medial pectoral nerve.
 Pectoral region 41

- Action:
 Protraction of the shoulder girdle thus assisting the serratus anterior
muscle.
 Depression of the shoulder.
 With fixed scapula,it can raise the ribs in forced inspiration

fig.35: muscles of the pectoral region

 Pectoral region 42

III- Subclavius (Fig. 35):
It is a slender muscle presents just below the clavicle.
- Origin:
From the upper surface of the 1st costo-chondral junction.
- Insertion:
Into a groove on the lower surface of the middle third of the clavicle.
- Nerve supply:
Nerve to subclavius (C5).
- Action:
It steadies the clavicle thus preventing excessive movements of the
shoulder girdle.

Formative assessment

I: M.C.Q:
Choose the correct answer:
1. The following muscle has double innervation:
a) pectoralis major
b) pectoralis minor
c) subclavius
d) deltoid

2. The axillary tail of the breast is related to:

a) Pectoral group of lymph nodes.
b) Apical group of lymph nodes
c) Central group of lymph nodes.
d) Humeral group of lumph nodes.

II.Give an explanation for the following:

Cancer breast may spread to the liver.


 Muscles of the back 43


CHAPTER 3

ILOs:
By the end of the lectures, the student should be able to:
 List the muscles of the back.
 Locate the site of attachment of the back muscles.
 Mention the nerve supply & actions of the back muscles.
 Recall boundaries and contents of lumbar triangle and triangle of
auscultation.
 Interpret some clinical problem related to lumbar triangle.
 Interpret clinical problem related to the nerve supply to trapezius.

MUSCLES CONNECTING THE UPPER LIMB WITH

VERTEBRAL COLUMN
(Muscles of the back)
These are the muscles of the upper limb situated in the back and connect the
limb to the vertebral column. They are supplied by the anterior primary rami of
the spinal nerves and they are arranged into two layers as follows (Fig. 36):
1- Muscles of the superficial layer: consists of two muscles:
1. The trapezius
2. The latissimus dorsi

2- Muscles of the deep

layer: consists of three
muscles:
1. The levator scapulae
2. The rhomboideus major
3. The rhomboideus minor
 Muscles of the back 44


1- Muscles of the superficial layer:

a) Trapezius (Fig. 37):

It is a large triangular muscle covering the upper half of the back. The two
muscles of both sides form together the outline of a trapezium.
- Origin:
 Back of the skull: from the external occipital protuberance and the
medial third of the superior nuchal line.
 Back of the neck: from the ligamentum nuchae and the spine of the 7th
cervical vertebra.
 Back of thorax: from the spines of all thoracic vertebrae and their
supraspinous ligaments.
- Insertion:
It has a V-shaped insertion as follows:
 The upper fibres: run downward and laterally and they are inserted into
the posterior border of the lateral third of the clavicle.
 Middle fibres: run horizontally and they are inserted into the medial
border of the acromion and the upper lip of the crest of the spine of the
scapula.
 Lower fibres: run upward and laterally and they are inserted into a rough
tubercle on the crest of the spine of the scapula (near the root of the
spine).
N.B. The insertion of the trapezius is embraced by the v-shaped origin of the deltoid.

- Nerve supply:
 Motor: spinal root of accessory nerve.
 Sensory: proprioceptive fibres from C3 and C4.

- Action:
 Acting with other muscles inserted in the scapula, it maintains the level of
the shoulder during active movements of the arm. If they are fatigued,
they let the shoulder drop.
 Its upper fibres elevate the shoulder girdle.
 Acting with the lower digitations of the serratus anterior, the upper and
lower fibers of trapezius rotate the scapula so that the glenoid cavity
looks upwards enabling the arm to be raised above the head.
 Acting with rhomboids, its middle fibres retract the scapula and brace
back the shoulder.

Applied anatomy:
Paralysis of the trapezius leads to shoulder drop.
 Muscles of the back 45


Fig. 37: Back view

attachments of
trapezius 


8th rib

Thoraco-lumbar fascia

Posterior part of

Fig. 38: Back view showing attachments of latissimus dorsi


 Muscles of the back 46


b) Latissimus dorsi (Fig. 38):

It is large triangular flat muscle covering the lower half of the back down
to the iliac crest. It has wide origin and narrow tendon of insertion.
- Origin:
It arises by:
1. Tendinous fibres from:
 Spines of the lower 6 thoracic vertebrae, undercover of the trapezius.
 Thoraco-lumbar fascia, which attaches the muscle to the lumbar and
sacral spines.
2. Fleshy fibres from:
 Posterior third of the outer lip of iliac crest.
 Lower 4 ribs interdigitating with the lower 4 digitations of external
abdominal oblique muscle.
 Few fibres from the dorsal aspect of the inferior angle of the scapula.

- Insertion: into the floor of the bicipital groove.

- Nerve supply: thoraco-dorsal nerve (nerve to latissimus dorsi).

- Action:
 Extention, medial rotation and adduction of the arm.
 Acting with sternocostal part of pectoralis major, it pulls the trunk
upwards or depresses the raised arm against resistance as in climbing,
rowing and swimming.
 Through its attachment to the ribs, it assists in violent expiration as in
coughing.
N.B.:
1. The upper border of the muscle crosses over the inferior angle of the scapula
and has triple relation to the teres major (Fig. 39) as follows: first, it lies
behind the teres major,then it curves below the teres major. At its insertion, it
comes in front of the teres major.
2. The latissimus dorsi, at its insertion, usually fuses with teres major forming the
posterior axillary fold.

- Related triangles:
1- Triangle of auscultation (Fig. 40): It is located medial to the lower
part of the scapula.
a. Boundaries:
 Above: lateral border of the trapezius.
 Below: upper border of the latissimus dorsi.
 Laterally: lower part of the medial border of the scapula
b. The floor is formed by:
 Rhomboideus major
 Sixth and seventh ribs and the space in between
 Muscles of the back 47


Breath sounds are clearly heard (auscultated) on this triangle, hence its
name.

2- Lumbar triangle (Fig. 40): it I situated just above the iliac crest and
might be a site of hernia (lumbar hernia).
a. Boundaries:
 Below: iliac crest.
 Medially: lateral border of latissimus dorsi.
 Laterally: vertical posterior border of external abdominal oblique
muscle.
b. The floor is formed by the internal abdominal oblique and tranversus
abdominis muscles.

Intertubercular
sulcus

Infra-
spinatus

Trapezius

Triangle of
auscultation

Latissimus
dorsi
Teres
major
External
oblique

Lumbar
triangle
Latissimus
dorsi
Iliac
crest

Fig. 39: Triple relation between latissimus Fig. 40: Triangles related to 
dorsi and teres major (Anterior view) latissimus dorsi (Back view)

 Muscles of the back 48


2- Muscles of the deep layer (Figs. 41, 42, 43):

a) Levator scapulae (Fig. 41):

- Origin: it arises by 4 tendinous slips from the transverse processes of the
upper 4 cervical vertebrae.
- Insertion: into the dorsal surface of the medial border of the scapula
above the root of the spine.
- Nerve supply:
 Nerve to rhomboids (dorsal scapular nerve, C5)
 Fibres from C3 and 4 (sensory proprioception fibers).
- Action:
 Acting with the upper fibres of trapezius, it elevates the shoulder girdle.
 Rotates the scapula so that the glenoid cavity looks downwards.
 Retractes the scapula.

b) Rhomboideus minor (Fig. 43):

- Origin: from the lower part of ligamentum nuchae, the spines of the 7th
cervical and the 1st thoracic vertebrae.
- Insertion: into the dorsal surface of the medial border of the scapula
opposite the root of the spine.
- Nerve supply: nerve to rhomboids (dorsal scapular nerve, C5).
- Action:
 Rotates the scapula so that the glenoid cavity looks downwards (acting
with the levator scapulae).
 Retracts the scapula and braces back the shoulder (acting with the middle
fibres of trapezius).

c) Rhomboideus major (Fig. 42):

- Origin: from the spines of the 2nd ,3rd,4th and 5th thoracic vertebrae and
their supraspinous ligaments.
- Insertion: into the dorsal surface of the medial border of the scapula
from the root of the spine to the inferior angle.
- Nerve supply: nerve to rhomboids (dorsal scapular nerve, C5).
- Action: the same as the rhomboideus minor.
 Muscles of the back 49


Spinous process of C7

Medial border of Rhomboid

scapula major Spinous process of T4

Fig. 41: Muscles of the back ( Deep layer) & Attachments of levator scapulae

T2
T5 Rhomboid major C7 Rhomboid minor
T1

 
Fig.42: Attachments of rhomboid major Fig.43: Attachments of rhomboid minor

 Muscles of the back 50


Formative assessment

I.MCQ:

1. Paralysis of the following muscle leads to shoulder drop:

a) Pectoralis major
b) Latissimus dorsi
c) trapezius
d) deltoid
2. The dorsal scapular nerve arises from:
a) Posterior cord of brachial plexus
b) Upper trunk of brachial plexus
c) Roots of brachial plexus
d) Medial cord of brachial plexus

II. Describe the boundaries and mention the importance of

lumbar triangle.


 Shoulder region 51


CHAPTER 4

ILOs:
By the end of the lectures, the student should be able to:
 List the muscles of the shoulder region
 Locate the site of attachment of the scapular muscles
 Mention the nerve supply & actions of the scapular muscles
 Describe the relations of deltoid muscle.
 Interpret clinical problem related to the nerve supply to deltoid.
 Cite the rotator cuff muscles

MUSCLES OF THE SHOULDER REGION

(scapular muscles)
These are group of muscles surrounding the shoulder joint and extending from
scapula to humerus (Fig. 44).They include the following muscles:
a) Deltoid
b) Supraspinatus
c) Infraspinatus
d) Teres major
e) Teres minor
f) Subscapularis

a) Deltoid (Figs. 45- a,b,c): it is a triangular thick muscle which forms the the
rounded contour of the shoulder.
- Origin: it has a V-shaped origin as follow:
 Anterior border of the lateral third of the clavicle (anterior fibers).
 Lateral border of acromion (middle fibers).
 Lower lip of the crest of spine of scapula (posterior fibers).
- Insertion: it is inserted in the deltoid tuberosity at the middle of the lateral
surface of the shaft of the humerus. The middle fibres are multipennate while
the anterior and posterior fibres are nearly parallel.
- Nerve supply: Circumflex (axillary) nerve (C 5,6).
- Action:
 The anterior fibres flex and medially rotates the arm
 The posterior fibres extend and laterally rotate the arm.
 The middle fibres abduct the arm from 15 to 90 degrees.

Clinical importance:
Paralysis of the deltoid muscle results in flattening of the shoulder and loss of
abduction of the shoulder joint from 15˚ to
 Shoulder region 52

- Relations of the deltoid:
The deltoid envelops the region of shoulder joint anteriorly, laterally and
posteriorly.

A. Deep relations (Figs. 46, 47): its deep surface covers the following
structures:
 Bones: upper end of humerus and coracoid process (with coraco-acromial
ligament).
 Muscles:
- Tendons of insertion of supra-spinatus, infra-spinatus, teres minor,
subscapularis, pectoralis minor.
- Tendons of origin of coraco-brachialis, both heads of biceps, long and
lateral heads of triceps.
 Vessels and Nerves: circumflex humeral vessels and axillary nerve around
the surgical neck of humerus.
 Bursa: subacromial bursa which separates deltoid from the upper aspect of
the capsule of the shoulder joint and tendon of supraspinatus.

B. Deltopectoral groove (Fig. 44):

It is a groove between the contiguous borders of the pectoralis major and the
deltoid and ends above, just below the clavicle, in the infraclavicular fossa. It
lodges the following structures:
- Uppermost part of cephalic vein.
- Deltoid branch of thoraco-acromial artery.
- Deltopectoral lymph nodes.

b) Supraspinatus (Fig. 47):

- Origin: from the medial two-third of the supraspinous fossa.

- Insertion: into the highest impression on the greater tuberosity.

- Nerve supply: suprascapular nerve (C5,6).

- Action:
 Helps to stabilize the head of the humerus in the glenoid cavity.
 t t o to 15 t t t to

.
 Shoulder region 53


Deltopectoral Supraspinatus
groove Deltoid muscle Infraspinatus

Teres minor

Teres major
Cephalic vein

(Anterior view) Fig. 44: Scapular muscles (Posterior view)

Deltoid Multipennate Lateral 1/3 of clavicle

Middle
Clavicle fibers
Acromion
Spine of
scapula Anterior
parallel
fibers

Deltoid
tuberosity (b)

(Anterior view)

Lateral border of acromion Acromial fibers

(multipennate)

posterior
parallel
 Lower lip of fibers
crest of the
Deltoid
(a) (Lateral view) spine
tubrosity

(c)
Fig. 45- a,b,c: attachments of deltoid muscle (Posterior view)

 Shoulder region 54


C) Infraspinatus (Fig. 47):

- Origin:
 From the medial two-third of the infraspinous fossa.
 From the deep fascia covering it.

- Insertion: into the middle impression on the back of the greater tuberosity.

- Nerve supply: suprascapular nerve (C5,6).

- Action:
 It steadies the head of the humerus in its position durind adbduction.
 It rotates the arm laterally.

d) Teres minor (Fig. 47):

- Origin: from the upper two-third of the dorsal surface of the lateral border of
the scapula.

- Insertion: into the lowest impression on the back of the greater tuberosity.

- Nerve supply: axillary (circumflex) nerve (C 5,6).

- Action:
 It steadies the head of the humerus in its position during abduction.
 It adducts and laterally rotates the arm.

e) Teres major:

- Origin: from the lower third of the dorsal surface of the lateral border of the
scapula.

- Insertion: into the medial lip of the biccipital groove of the humerus.

- Nerve suppy: lower subscapular nerve (C 5,6).

- Action: adduction, medial rotation and extention of the arm.

f) Subscapularis (Fig. 48):

It fits the subscapular fossa, on the front of the scapula and forms part of the
posterior wall of axilla.

- Origin: from the medial two-third of the subscapular fossa.

 Shoulder region 55


Fig. 46: Deep relations of deltoid (Post. view)

 Shoulder region 56


- Insertion: into the lesser tuberosity of the humeus.

- Nerve supply: Upper and lower subscapular nerves (C 5,6)

.
- Action:
 Stabilization of the anterior aspect of the shoulder joint.
 Medial rotation and adduction of the arm.

Clinical importance:
Subscapularis together with the supraspinatus,infraspinatus and teres minor
steady the head of the humerus in the glenoid cavity during movements of the
arm. These four muscles blend with the capsule of the shoulder joint and are
called the "musculo- tendinous cuff of shoulder" or "rotator muscle
cuff".

Lesser tuberosity

Fig. 48: Attachments of subscapularis (Anterior view)

 Shoulder region 57

MUSCLES CONNECTING THE UPPER LIMB WITH THE
THORACIC WALL

a) Pectoralis major (see pectoral region)

b) Pectoralis minor (see pectoral region)
c) Subclavius (see pectoral region)
d) Serratus anterior

d) Serratus anterior (Fig. 49):

It is a large flat muscle which covers the upper part of the side of the chest.

- Origin:
 It arises by 8 digitations from the outer surfaces of the upper 8 ribs
midway between their angles and their costal cartilages.
 The 1st digitation is the largest and arises from the 1st and 2nd ribs as well
as from a fibrous arch extending between these two ribs.
 The lower 4 digitations interdigitate with the upper 4 slips of the external
abdominal oblique muscle.

- Insertion: the muscle forms a broad sheet which curves backward on the
side of the chest wall to be inserted in the ventral surface of the medial
border of the scapula as follows:
 The 1st digitation is inserted into the superior angle.
 The 2nd and 3rd digitations fan out to be inserted into the whole length of
the mediual border.
 The lower 5 digitations converge to be inserted into the inferior angle.

- Nerve supply: nerve to serratus anterior (long thoracic nerve, C5,6,7). The
nerve arises from the root of brachia plexus and descends vertically on the
outer surface of the serratus anterior, in the midaxillary line.

- Action:
 The muscle as a whole is the main protractor of the shoulder (powerfull
protractor), where it draws the scapula forwards assissted by the
pectoralis minor muscle.
 Acting with the upper and lower fibers of trapezius, the lower five
digitations of the serratus anterior muscle rotate the scapula so that the
glenoid cavity looks upwards.
 It helps to fix the scapula to the chest wall, in cases of pushing against
resistance.
 When the scapula is fixed, the muscle pulls on the ribs in forced
inspiration (accessory muscle of respiration).
 Shoulder region 58


Applied anatomy:
because the muscle fixes the scapula against the chest wall, so paralysis of the
serratus anterior muscle results in projection of the inferior angle and medial
border of the scapula backwards, in cases of pushing against resistance. This
condition is called winging of the scapula (Fig. 50).

Long thoracic N.

Fig. 50: Winging of scapula

Fig. 49: Attachments of Serratus Anterior

(Lateral view)
 Shoulder region 59

Quadrangular and Triangular Spaces

They are intermascular spaces lying just below the shoulder joint.

A. Quadrangular space (laterally) (Figs. 51, 52):

- Boundaries:
 Above: by the teres minor (seen from behind), the subscapularis (seen
from in front) and the capsule of the shoulder joint.
 Below: by teres major.
 Medially: by long head of triceps.
 Laterally: by surgical neck of humerus.

- Contents:
 Posterior circumflex humeral vessels.
 Axillary (circumflex) nerve.

B. Upper triangular space (medially) (Figs. 51, 52)

- Boundaries:
 Above: by teres minor (seen from behind) and subscapularis (seen from in
front).
 Below: by teres major.
 Laterally: by long head of triceps.

- Contents: it transmits only the circumflex scapular artery.

C. Lower triangular space (triangular interval) (Figs. 51, 52) : it

lies just lateral to the long head of triceps and is separated from the
quadrangular space by the teres major muscle.

- Boundaries:
 Above by: teres major.
 Medially by: long head of triceps.
 Laterally by: lateral head of triceps and the shaft of humerus.

- Contents: radial nerve and profunda brachii vessels.

 Shoulder region 60


Quadrangular space
 Axillary nerve Subscapularis
 Posterior circumflex
humeral Upper triangular
space
Lower triangular space
Teres major
 Radial nerve
 Profunda brachii a.

Long head of triceps

Fig. 51: Quadrangular & triangular Latissimus dorsi

spaces (Anterior view) 

Teres minor
Quadrangular
space

Upper triangular
space
Teres major

Lower triangular
space

Fig. 52: Quadrangular &

triangular spaces
(Posterior view)

 Shoulder region 61


FORMATIVE ASSESSMENT

I. Give an explanation for the following:

a. Dislocation of the shoulder joint is more common inferiorly.

b. Winging of the scapula is more common during radical mastectomy and

removal of axillary lymph nodes.

III. Choose the correct answer:

1. Paralysis of the following muscle leads to flat shoulder:
a) Pectoralis major
b) Latissimus dorsi
c) Trapezius
d) Deltoid
2. Winging of the scapula is due to:
a) Paralysis of serratus anterior
b) Paralysis of pectoralis major
c) Paralysis of deltoid
d) Paralysis of teres major


 Axilla 62


CHAPTER 5

ILOs:
By the end of the lectures, the student should be able to:
 Describe the site and boundaries of the axilla.
 List contents of the axilla
 Determine the site of brachial plexus.
 Describe the stages of the brachial plexus
 Enumerate branches of brachial plexus
 Recognize the site and parts of axillary artery
 Describe relations of axillary artery.
 List the arteries sharing in anastomoses around scapula and surgical neck
 Explain the clinical importance of the anastomosis around scapula

AXILLA
- Site: it lis a pyramidal region, situated between the upper part of the side of
the chest wall and the upper part of the medial side of the arm.
- Boundaries (Figs. 53- a, b, 54): it is a four sided pyramid having an apex,
a base (or floor) and four walls (anterior, posterior, lateral and medial).
 Apex (cervico-axillary canal): it is a triangular interval directed
upwards and medially towards the root of the neck communicating it
with the axilla and through it the axillary vessels and nerves enter the
axilla from the neck. The apex is bounded by:
 Outer border of the first rib, medially.
 Superior border of scapula, posteriorly.
 Posterior surface of the clavicle, anteriorly.

 Anterior (pectoral) wall: formed of two layers:

1. Superficial layer: is formed by pectoralis major muscle.
2. Deep layer (the axillary septum), formed from above downwards by:
 Subclavius muscle
 Clavi-pectoral fascia
 Pectoralis minor muscle
 Suspensory ligament of the axilla, attached below to the axillary
fascia (deep fascia in the base of axilla)
N.B. Anterior fold of axilla: is the lower border of the anterior wall and is formed
by the twisted lower border of pectoralis major around which skin and fascia are
folded backwards to be continuous with those of the base of axilla.
 Posterior (subscapular) wall: is formed from above downwards by:
 Subscapularis (its lateral part)
 Teres major
 Latissimus dorsi muscle.
 Axilla 63



(a)






Subscapularis 
Long head of biceps
Short head of ciceps
Coracobrachialis

Latissimus dorsi
Teres major

Biceps

(b)

Fig. 53- a,b: Boundaries of axilla (Anterior views)
 Axilla 64

 Lateral (humeral) wall: is the narrowest wall. It is formed by:
 Bicipital groove of humerus
 Short head of biceps muscle.
 coracobrachialis muscles.

 Medial (costal) wall: is formed by:

 The upper four ribs and their corresponding intercostal muscles.
 The upper part of serratus anterior muscle.
 Base (floor): looks downwards and is formed by:
 Skin (rich in hairs, sweat and sebaceous glands).
 Superficial fascia.
 Deep (axillary) fascia: Receives the attachment of suspensory
ligament of the axilla.
N.B.
Posterior fold of axilla: is the lower border of the posterior wall and is formed by
teres major and latissimus dorsi muscles.
The posterior wall contains two intermuscular spaces (upper triangular &
quadrangular spaces) which connect the axilla with the back of shoulder region.
Anterior wall of the axilla is slightly shorter than its posterior wall. Therefore, the
posterior fold of the axilla lies at a slightly lower level than that of the anterior
fold.

- Contents of axilla:
1- Vessels:
 Axillary artery and its branches.
 Axillary vein and its tributaries.

2- Nerves: cords of brachial plexus and their branches, the long thoracic
nerve and the intercostobrachial nerve which is the lateral cutaneous
branch of the 2nd thoracic nerve crossing the axilla to reach the medial
side of the arm.

3- Lymph Nodes: five groups of axillary lymph nodes (anterior, posterior,

lateral, central and apical).

4- Special contents:
 Tail of mammary gland.
 Axillary fat and loose areolar tissue

N.B. The axillary vessels and brachial plexus run from the apex to the base along the
lateral wall of axilla nearer to the anterior than the posterior wall.
 Axilla 65


Fig. 54: Walls of Axilla

 Axilla 66


BRACHIAL PLEXUS

- Formation (Stages) (Fig. 55): it is a collection of nerves, which lie

partly in the neck and partly in the axilla. It consists of roots, trunks and
cords.
A. Roots: is formed by the ventral (anterior) primary rami of the 5, 6, 7
and 8 cervical and 1st thoracic nerves. The plexus may be:
1. Prefixed plexus: if the 5th cervical root receives a contribution from
the 4th cervical nerve.
2. Postfixed plexus: if the 1st thoracic root receives a branch from the
2nd thoracic nerve.

B. Trunks:
1. Upper trunk is formed by union of 5th and 6th cervical roots.
2. Middle trunk is formed by 7th cervical root only.
3. Lower trunk is formed by union of 8th cervical and 1st thoracic roots.

The three trunks lie above the clavicle, in the neck

C. Divisions: each trunk divides, behind the clavicle, into anterior

(ventral) and posterior (dorsal) divisions, to supply the flexor and
extensor sides, respectively.

D. Cords: the plexus consists of three cords which lie in the axilla.
1. Medial cord is formed by the anterior division of the lower trunk.
2. Lateral cord is formed by fusion of the anterior divisions of the
upper and middle trunks.
3. Posterior cord is formed by fusion of the posterior divisions of the
three trunks.
N.B. All branches of both lateral and medial cords supply the flexor side, while
all branches of the posterior cord supply the extensor side of the upper
limb.

- Site (Fig. 56):

A. Roots and trunks lie in the neck: the roots lie in the neck deep to
scalenus anterior muscle, while the trunks lie in the posterior triangle
of the neck.
B. Divisions: lie in the apex of axilla behind the clavicle.
C. Cords and its branches: lie in the axilla
 Axilla 67


Fig.64: Formation and branches of brachial plexus

 Axilla 68


- Branches of the brachial plexus (Fig. 55): arise from the roots, the
upper trunk and the three cords.

A- Branches of the Roots:

1. Nerve to rhomboids (dorsal scapular Nerve):
 Arises from the root of C5.
 Descends along medial (vertebral) border of scapula deep to
levator scapulae and rhomboid muscles, accompanied by deep
branch of transverse cervical artery (dorsal scapular artery).
 Supplies rhomboids minor and major and gives a twig to levator
scapulae.

2. Nerve to serratus anterior (long thoracic Nerve):

 It arises from the roots of C5, 6 and 7.
 It descends behind the brachial plexus to enter the axilla through its
apex, where it descends behind the 1st part of axillary artery.
 Then it descends vertically, in the midaxillary line, on the outer
surface of serratus anterior muscle supplying it.

B- Branches of the Trunks (only from the upper trunk):

1. Nerve to Subclavius (C5 and 6):
It arises from the upper trunk and descends in front of the brachial
plexus and subclavian vessels to reach the subclavius muscle.

2. Suprascapular Nerve (C5 and 6):

 It arises from the upper trunk and runs downwards and laterally
in the posterior triangle of the neck to reach the suprascapular
notch.
 It passes through the supra-scapular foramen (below the supra-
scapular ligament) to reach the supra-spinous fossa where it
runs deep to supraspinatus muscle and supplies it.
 Then it descends through the spino-glenoid notch to reach the
infra-spinous fossa where it ends by supplying infra-spinatus
muscle, through its deep surface.
 It gives also articular branches to supply the shoulder joint.

C- Branches of the Cords:

 Branches of Lateral Cord:
1. Musculocutaneous nerve (C5,6 & 7): is the largest branch.
2. Lateral root of median nerve (C5,6 &7)
3. Lateral pectoral nerve (C5, 6 and 7): is larger than the medial
pectoral nerve. It pierces clavi-pectoral fascia and ends by
supplying the pectoralis major muscle.
 Axilla 69

 Branches of Medial Cord:
1. Ulnar nerve (C7,8 and T1): is the largest branch.
2. Medial root of median nerve (C8 and T1).
3. Medial pectoral nerve (C8 and T1): it pierces and supplies
pectoralis minor and ends by supplying pectoralis major.
4. Medial cutaneous nerve of the arm (C8 and T1): supplies the
skin on the medial side of the lower half of the arm.
5. Medial cutaneous nerve of the forearm (C8 and T1):
 Descends medial to the third part of axillary artery and upper
half of the brachial artery.
 At the middle of the arm (opposite the insertion of coraco-
brachialis), it pierces the deep fascia close to the basilic vein to
become superficial.
 Above the elbow, it divides into anterior and posterior branches
which descend on the medial side of the forearm to the wrist,
supplying the skin of this region.

Fig. 56: Formatiom of brachial plexus &

location (Anterior view)
 Axilla 70

 Branches of the Posterior Cord (Fig. 57):
1. Radial nerve (C5,6,7,8 and T1): is the larger of the two terminal
branches of the posterior cord (will be discussed later) .
2. Axillary (circumflex) nerve (C5,6) (Figs. 57, 58):
- Origin: is the smaller of the two terminal branches of the cord.
- Course:
 It passes downwards and laterally on the subscapularis muscle
behind the third part of axillary artery.
 On reaching the lower border of subscapularis, it passes
backwards through the quadrangular space (accompanied by
posterior circumflex humeral artery) where they lie below the
capsule of the shoulder joint.
 It turns around the back of the surgical neck of the humerus
where it gives an articular branch to the shoulder joint.

- It ends by dividing into:

 Anterior branch: it continues its course round the surgical neck
to end near the anterior border of deltoid muscle, supplying it
through its deep surface.
 Posterior branch: it gives a branch to the teres minor and then
curves around the posterior border of deltoid to become the
upper lateral cutaneous nerve of the arm which supplies the skin
over the lower half of the deltoid.

3. Upper subscapular nerve (C5 and 6): supplies the upper part of
the subscapularis muscle.

4. Lower subscapular nerve (C 5 and 6): runs downwards and

laterally to supply the lower part of subscapularis muscle and teres
major muscle.

5. Nerve to Latissimus Dorsi (Thoraco-dorsal nerve): (C6, 7 & 8)

 It arises from the posterior cord between upper and lower
subscapular nerves.
 It descends through the axilla till it reaches the lower border of
subscapularis muscle where it is accompanied by the thoraco-
dorsal artery (the continuation of subscapular artery). They
follow the lower border of subscapularis to end at the inferior
angle of the scapula by supplying latissimus dorsi muscle.
 Axilla 71

Fig. 57: Branches of
the posterior cord
(Anteromedial view)

 Axilla 72


Axillary Artery

- Beginning (Fig. 59): it begins at the outer border of the first rib as the
continuation of the subclavian artery.
- Course and parts (Figs. 59, 60):
It enters the axilla through its apex. Then it runs downwards and laterally along
the lateral wall of the axilla. The axillary artery passes deep to the pectoralis
minor muscle which divides it into three parts:
 First part: above pectoralis minor.
 Second part: deep to pectoralis minor.
 Third part (the longest part): below pectoralis minor.
- End: it ends at the lower border of the teres major muscle (lower limit of
axilla) where it becomes the brachial artery.
- Relations (Figs. 60, 61):
 Relations of the First part:
* Medially: axillary vein
* Laterally: the lateral and posterior cords of brachial plexus.
* Anteriorly:
 Clavicular part of pectoralis major muscle
 Subclavius muscle
 Clavipectoral fascia
 Termination of the cephalic vein
* Posteriorly:
 First intercostal space
 First digitations of serratus anterior
 Nerve to serratus anterior (long thoracic nerve)
 Medial cord of brachial plexus

 Relations of the second part

* Anteriorly: Pectoralis major and minor muscles.
* Posteriorly:
 Posterior cord of brachial plexus
 Subscapularis muscle

* Medially:
 Medial cord of brachial plexus
 Axillary vein

* Laterally:
 Lateral cord
 Coraco-brachialis muscle
 Axilla 73


Fig.59: Axillary artery course

& branches (anterior view)

Fig.60: Relations of Axillary artery

(Anterior view)


 Axilla 74


 Relations of the third part: it is partly superficial and its pulsations

can be felt at the posterior fold of axilla.
* Anteriorly:
 Medial root of median nerve crossing from medial to lateral.
 Pectoralis major muscle.
N.B. Since the anterior wall of the axilla is slightly shorter than its
posterior wall, the lowermost part of the axillary artery becomes
superficial (only covered by skin and fascia) below the lower border of
pectoralis major.
* Posteriorly:
 Radial and axillary nerves
 The posterior wall of axilla: subscapularis, teres major and
latissimus dorsi (from above downwards).
* Laterally, from the artery outwards:
 Lateral root of median nerve
 Trunk of median nerve
 Musculo-cutaneous nerve
 Coraco-brachialis muscle
* Medially, from the artery inwards:
 Ulnar nerve
 Medial cutaneous nerve of forearm
 Axillary vein
 Medial cutaneous nerve of arm (medial to the vein)

Fig. 61: Relations of the axillary

artery to bracxhial plexus (Ant. View)
(Anterior view)
 Axilla 75


- Branches of the axillary artery (Fig. 59):

 First part, gives one branch:
The superior thoracic artery: arises at the lower border of subclavius
muscle to supply it and anastomoses with intercostal arteries.

 Second part gives two branches:

1. Acromio-thoracic artery:
It is a short trunk arising behind the upper border of pectoralis minor. It
pierces the clavi-pectoral fascia and ends by dividing into four branches:
a. Acromial branch: runs towards the acromion
b. Pectoral branch (the largest branch): descends between the
two pectoral muscles supplying them and the breast.
c. Clavicular branch: supplies subclavius muscle and sterno-
clavicular joint.
d. Deltoid branch: passes in the deltopectoral groove and
supplies the deltoid and pectoralis major muscle.

2.Lateral thoracic artery:

It arises behind the lower border of pectoralis minor and runs along this
lower border to reach the side of the chest. It supplys the serratus
anterior, the pectoral muscles and subscapularis. In females, it is large
and gives lateral mammary branches supplying the lateral part of the
gland.
 Third part: Gives three arteries:
1. Subscapular Artery (the largest branch of the axillary artery): It
arises at the lower border of subscapularis muscle where it gives a
large branch called circumflex scapular artery. Below this branch
the artery diminishes in size and continues as thoraco-dorsal artery
which is accompanied by nerve to latissimus dorsi (thoraco- dorsal
nerve). It ends at the inferior angle of the scapula by supplying
latissimus muscle, and sharing in the anastomosis around the scapula.
* The circumflex scapular artery: is usually larger than the
continuation of the subscapular artery (the thoraco-dorsal artery). It
curves around the lateral border of scapula traversing the upper
triangular space. Then it reachs the infra-spinous fossa, under cover of
the teres minor muscle, where it shares in the anastomosis around the
scapula.

2. Anterior circumflex humeral artery (a very small artery): arises at

the lower border of subscapularis muscle. It runs in front of the surgical
neck of humerus. It gives off an ascending branch to supply shoulder
joint and ends by anastomosing with the posterior circumflex humeral
artery.
 Axilla 76

3. Posterior circumflex humeral artery: arises at lower border of
subscapularis muscle. It runs backwards with axillary nerve through the
quadrangular space and winds round the surgical neck of humerus. On
the back, it gives off a descending branch to anastomose with an
ascending branch of the profunda brachii artery and also gives an
ascending branch to anastomose with suprascapular artery all together
forming a cruciate anastomosis.Finally, it anastomoses with anterior
circumflex humeral artery.
Surface anatomy:
With the arm abducted to a right angle, the axillary artery is represented by
a horizontal line drawn between two points:
Point 1: at the midclavicular point.
Point 2: at the posterior fold of the axilla where the pulsation of the axillary
artery can be felt.

- Anastomoses of the axillary artery

The branches of the axillary artery share in the following anstomoses:
I. Anastomosis around the scapula (Fig. 62):
It is an important anastomosis between branches of:
1. First part of subclavian artery (in the neck) giving the following branches:
a. Supra-scapular artery
b. Deep branch of transverse cervical artery (branch from thyro-
cervical trunk).
2. Third part of axillary artery in the axilla giving the following branches:
a. Subscapular artery
b. Circumflex scapular artery (branch from subscapular artery).
3. Descending thoracic aorta giving the posterior intercostal arteries.

Clinical Importance:
Through this anastomosis blood can by-pass an obstruction in the artery
between the first part of subclavian artery and third part of axillary artery, to
maintain blood flow to the upper limb.Through the anastomosis with the
posterior intercostal arteries, blood flow can be maintained to the lower half of
the body in case of a congenital anomaly called coarctation of aorta.
 Axilla 77


II. Anastomosis around surgical neck of humerus (Cruciate

anastomosis):
It is an important anastomosis between the following branches (Fig. 63):
1. Subclavian artery: descending branch of the supra-scapular artery.
2. Third part of axillary artery:
- Anterior circumflex humeral artery.
- Posterior circumflex humeral artery.
3. Brachial artery: ascending branch of profunda brachii artery.

Fig. 62: Anastomosis around

scapula (Anterior view)

Anastomosis with
the posterior
intercostal arteries


 Axilla 78


III. Anastomosis around the shoulder joint

The arteries sharing in the anastomosis are as follows:
1. Acromial and deltoid branches of thoraco-acromial artery (from axillary)
2. Suprascapular artery (from the subclavian)
3. Ascending branch of the anterior circumflex humeral artery (from the
axillary)

Fig. 63: Anastomosis around

surgical neck (Anterior view) 

 

Clavicle

Scapula

Lateral thoracic
artery

Axillary Vein
(Fig. 64)

- Beginning: it begins at the lower border of teres major muscle by the

union of the basilic vein and the two venae comitantes of the brachial artery.
- Course: it ascends on the medial side of the axillary artery in the axilla.
- End: at the outer border of the 1st rib at the apex of the axilla by becoming
the subclavian vein.
- Tributaries: they correspond to the branches of axillary artery in addition
to cephalic vein, venae comitantes of brachial artery and basilic vein.
 Axilla 79


Fig. 64: Axillary vein (Anterior view)

AXILLARY LYMPH NODES

The axillary lymph nodes are about 20 to 30 arranged anatomically into 5 groups
which lie in relation to the walls and apex of the axilla, usually along the blood
vessels. They are as follows (Figs. 65, 66):

1. Anterior (pectoral) group: these nodes lie along the lower border
of the pectoralis minor in relation to the lateral thoracic artery.
 They receive afferents from:
 Central part and lateral quadrant of the mammary gland.
 Anterolateral wall of the trunk above the level of the umbilicus.
 They sends efferents to:
 Cental nods
 Apical nodes
2. Posterior (subscapular) group: lie on the posterior wall of the
axilla along the subscapular artery.
 They receive afferents from:
 Posterior wall of the trunk as far as the iliac crest.
 The back of the shoulder region.
 They send efferents to:
 Central nodes.
 Apical nodes
 Axilla 80


3. Lateral (humeral) group: they lie medial to and behind the axillary
vein in the lateral wall of the axilla.
 They send afferents from the whole of the upper limnb except the areas
drained by the lymphatics accompanying the cephalic vein.

 The send efferents to:

 Cental nodes
 Apical nodes
 Lower deep cervical nodes, in the root of the neck.

4. Central group: lie in the fat just above the base of the axilla.
 They receive afferents from all the preceding groups of axillary lymph
nodes.

 They send efferents to the apical group.

5. Apical group: these nodes are situated at the apex of the axilla along
the medial side of the axillary vein. They lie partly deep and partly above
the upper border of the pectoralis minor muscle just below the clavicle and
clavipectoral fascia.

 They receives lymph (afferent) from:

 All the other groups of axillary lymph nodes.
 Directly from the upper and peripheral part of the mammary gland.
 Areas of the upper limb drained by lymphatics accompanied the
cephalic vein.

 They send efferents as follows:

 Few vessels pass to the lower deep cervical nodes.
 The majority of the vessels end in the subclavian lymph trunk.

N.B.
The axillary lymph nodes are divided surgically into 3 levels:
* Level 1: lies below pectoralis minor, include the anterior, posterior
and lateral groups.
*Level 2: lies deep to pectoralis minor, includes the central group.
*Level 3: lies above the pectoralis minor, includes the apical group.
 Axilla 81


Fig. 66: Axillary lymph nodes

(Sagittal section)
 Axilla 82


Formative assessment

I. Explain:
How the circulation of the upper limb is maintained in a case of
coarctation of aorta.
II. Choose the correct answer:
The following group of axillary lymph nodes receives lymphatic drainage
directly from the anterolateral wall of the trunk above the level of the
umbilicus:
a. Pectoral
b. Subscapular
c. Humeral
d. Central


 Arm 83

CHAPTER 6

ILOs:
By the end of the lectures, the student should be able to:
 Recognize site of muscles of arm.
 Describe origin , insertion , nerve supply and actions of arm muscles
 List the nerves and vessels of arm.
 Describe course of nerves of arm
 Describe relations of brachial artery.
 Enumerate branches of brachial artery
 List the arteries sharing in anastomoses around elbow
 Explain the clinical importance of the anastomosis around elbow

ARM

Deep Fascia of the Arm (Brachial Fascia)

 It forms a sheath for the muscles of the arm. It is thin on front and thick
on the back.
 On each side, this fascia sends deeply among the muscles of the arm two
fibrous septa called the lateral and medial intermuscular septa. Separating
the flexor muscles (anterior group) from the extensor muscles (posterior
group). The two septa provide additional surfaces for muscle attachment
(Fig.67).
A. Lateral Intermuscular Septum
 It is attached to the humerus along its lateral border, lateral supra-
condylar ridge down to the lateral epicondyle.
 It gives origin to the medial head of triceps (behind) and to brachialis,
brachio-radialis and extensor carpi radialis longus (in front).
 It is pierced by radial nerve and radial collateral artery in the lower third
of the arm.
B. Medial Intermuscular Septum
 It is thicker and is attached to the humerus along its medial border,
medial supra-condylar ridge down to the medial epicondyle.
 It gives origin to the medial head of triceps (behind) and to brachialis (in
front).
 It is pierced by ulnar nerve and superior ulnar collateral artery at the
middle of the arm. Just above the elbow, it is pierced by inferior ulnar
collateral artery.
MUSCLES OF THE ARM
The arm is divided by the medial and lateral intermuscular septa into two
compartments:
* Anterior (ventral or Flexor) compartment: contains 3 muscles (the flexor
group).
 Arm 84

* Posterior (Dorsal or extensor) compartment: contains one muscle (the
Extensor group).

I. The Flexor Group of the Arm


It consists of three muscles arranged in two layers; biceps and coraco-
brachialis lying superficially and brachialis lying deep to them (Fig.68).
 They are supplied by musculo-cutaneous nerve. In addition, the small
lateral part of brachialis is also supplied by a twig from radial nerve.
1. Biceps Brachii Muscle (Figs. 68, 69):

- Origin: it arises by two heads as follows:

a. Short head: from the tip of the coracoid process of scapula in common
with coraco-brachialis muscle.
b. Long head:
It arises by a long tendon from the supra-glenoid tubercle inside the
fibrous capsule of shoulder joint where it invaginates the synovial
membrane of the joint, which cover the tendon completely. The tendon
arches laterally over the head of humerus and leave the capsule through
an opening in its anterior wall with a prolongation of the synovial
membrane called synovial sheath.Then it descends in the bicipital groove
behind the transverse humeral ligament which retains the tendon in the
groove.

- Insertion: the two heads unite with each other in the lower third of the
arm to be inserted by.
 Bicipital tendon: into the rough posterior part of the radial tuberosity with
a bursa separating it from the smooth anterior part of the radial
tuberosity.
 Bicipital aponeurosis: arises from the medial side of the biceps tendon
and passes obliquely downwards and medially to blend with the deep
fascia covering the flexors of the forearm (in the roof of the cubital
fossa).
- Action:
 Being inserted into the posterior part of radial tuberosity, it is a powerful
supinator.
 It flexes the elbow (helping brachialis).
 Tendon of long head steadies the head of humerus preventing its
upwards gliding.
 It assists in flexion of the shoulder joint.

N.B. The bicipital aponeurosis: is situated in the roof of the cubital fossa and
separates the median cubital vein, lying superficial to it, from the median nerve
and terminal part of the brachial artery, lying deep to it.
 Arm 85

Fig. 68: Flexor group
of arm

1 Long head of
biceps muscle

Short head of
2 biceps muscle

3
4 Coracobrachialis
muscle

6 8 7  Brachialis muscle

1- Biceps muscle Biceps muscle (cut)

2- Brachialis muscle
3- Lateral head of triceps
4- Long head of triceps
5-Medial; head of triceps Bicepital aponeurosis
6- Lateral intermuscular
septum Ulnar tuberosity
7- Medial intermuscular Fig. 67: Cross
septum section in the
8- Humerus arm Radial tuberosity

 Arm 86

2. Coraco-Brachialis Muscle (Fig.69):
- Origin: from the tip of coracoid process in common with the short head of
biceps.
- Insertion: into a rough impression at the middle of the medial border of
the shaft of humerus.
- Action:
 It assists in flexion of the shoulder joint.
 It assists in adduction of abducted arm.
- Relations:
 It is pierced by the musculo-cutaneous nerve.
 It lies medial to the short head of biceps muscle.
3. Brachialis Muscle (Figs. 68, 69):
- Origin:

From the lower half of the front of the shaft of humerus, embracing the
insertion of deltoid.
 From the anterior aspects of medial and lateral intermuscular septa.
- Insertion: its fibers converge to form a thick tendon which descends close
to the anterior aspect of the capsule of elbow joint to be inserted into the
rough anterior surface of coronoid process and ulnar tuberosity.
- Action: the main flexor of the elbow.
- Relations:
 Brachialis is deep to the biceps with the musculocutaneous nerve in
between.
 Brachial artery and median nerve run superficial to it just medial to the
bicipital tendon.

II. The Extensor Group Of The Arm

Triceps Muscle (Figs. 70, 71 72):
- Origin: By three heads as follows:
 Long head: arises by a flat tendon from infra-glenoid tubercle.
 Lateral head: has a linear origin from the upper lip of the spiral groove, on
the posterior surface of the upper half of the humerus.
 Medial head: it arises from the posterior surface of the shaft of humerus
below the spiral groove. It has additional origin from the back of the
medial and lateral inter-muscular septa.
- Insertion:
 The muscle is inserted by a common tendon which descends behind the
capsule of the elbow joint to be inserted into the upper surface of
olecranon process.
 Few fibers (called Articularis cubiti) emerge from the deep surface of
lower part of triceps to insert into the posterior part of fibrous capsule of
the elbow joint.
 Arm 87

- Nerve Supply: from the radial nerve as follows:
 In the axilla, it gives branches to long and medial heads.
 In the spiral groove, it gives branches to lateral and medial heads.
- Action:
 It is the powerful extensor of the elbow joint.
 Articularis cubiti draws up the posterior part of the capsule of the elbow
joint during extension of the forearm, preventing it from being insinuated
inside the joint.


 Arm 88

Brachial Artery
- Beginning (Fig. 73): at the lower border of teres major muscle as a
continuation of axillary artery.
- Course (Fig. 73): in the upper part of the arm the artery descends on the
medial side of the shaft of humerus, but gradually it passes to the front of
the arm until it descends midway between lateral and medial epicondyles
of the humerus to enter the cubital fossa.
- End: it ends in the cubital fossa 1 cm below the elbow joint at the level of
neck of radius by dividing into two terminal branches; radial and ulnar
arteries.
- Relations (Figs. 73, 74, 75, 76): The artery is superficial throughout its
entire course being covered only with the skin superficial and deep
fasciae. But it is slightly overlapped by coraco-brachialis and the medial
edge of the biceps muscle.

 In the upper half of the arm: the artery has the following relations:
* Anteriorly: skin, superficial fascia and deep fascia.
* Posteriorly: from above downwards it lies on:
 Long head of triceps separated from it by radial nerve.
 Medial head of triceps.
 Insertion of coraco-brachialis.
* Laterally:
 Median nerve
 Coraco-brachialis
 Short head of biceps
* Medially:
 Ulnar nerve
 Medial cutaneous nerve of forearm
 Basilic vein
 At the middle of the arm (opposite the insertion of the coraco-
brachialis) the following changes occur:
 Median nerve crosses the brachial artery from lateral to medial
(either in front or behind the artery).
 Ulnar nerve leaves the brachial artery by piercing the medial
intermuscular septum to reach the posterior compartment of the
arm.
 Basilic vein and medial cutaneous nerve of the forearm leave
the brachial artery by piercing the deep fascia to become
superficial.

 In the lower half of the arm: the artery has the following relations:
* Anteriorly: skin, superficial and deep fasciae.
 Arm 89



 Arm 90


* Posteriorly: brachialis muscle separating the artery from the lower

half of the shaft of humerus.
* Laterally: biceps muscle.
* Medially: median nerve.

 In the cubital fossa: the artery has the following relations:

* Anteriorly: in addition to skin and fasciae, the artery is crossed
anteriorly by the bicipital aponeurosis which separates the artery
from median cubital vein, more superficial.
* Posteriorly: tendon of brachialis, separating the artery from
capsule of elbow joint.
* Laterally: biceps tendon.
* Medially: median nerve.

N.B. The artery is accompanied by two venae comitantes.

- Branches (Figs. 77, 78)

1. Profunda brachii artery:
- Origin: It is the largest and highest branch, arising from the
posteromedial aspect of the brachial artery, just below the lower
border of the teres major.
- Course: It accompanies the radial nerve. It runs backwards between
the long and medial heads of triceps passing, through the lower
triangular space to reach the spiral groove on the back of the shaft
of humerus where it is covered by the lateral head of the triceps
- Branches:
a. Muscular branches to supply triceps muscle.
b. A small nutrient artery to humerus (may be absent).
c. An ascending branch to anastomose with the descending
branch of posterior circumflex humeral artery. (Cruciate anastomosis
on the back of surgical neck of humerus).
d. Two terminal descending branches:
1. Anterior descending branch (Radial collateral) which
accompanies radial nerve, both pierce the lateral
intermuscular septum to reach the front of the lateral
epicondyle of humerus where it anastomses with the radial
recurrent artery (anastomosis around the elbow).
2. Posterior descending branch (middle collateral): descends to
the back of lateral epicondyle of the humerus to
anastomoses with the posterior interosseous recurrent
artery (anastomosis around the elbow).


 Arm 91


Fig. 77: Profunda brachii Fig. 78: Branches of brachial artery &
artery & radial nerve in spiral anastomosis around elbow (Anterior
groove view)
(Posterior view)
 Arm 92

2. Superior ulnar collateral artery:
- It arises about the middle of the arm, opposite the insertion of
coraco-brachialis.
- It accompanies the ulnar nerve; both pierce medial intermuscular
septum to reach posterior compartment of the arm where it
descends to the back of medial epicondyle of humerus to
anastomose with posterior ulnar recurrent artery (anastomosis
around the elbow).
3. Inferior ulnar collateral artery:
- Arises 5 cm above the elbow joint.
- It gives an anterior branch which descends to anastomose with the
anterior ulnar recurrent artery in front of the medial epicondyle.
- Then it pierces the medial intermuscular septum to share in the
anastomosis behind the medial epicondyle. Then it turns around the
back of the humerus above the olecranon fossa to join the posterior
descending branch of profunda brachii.
4. Nutrient artery to the humerus:
- It rises about the middle of the arm opposite the insertion of coraco-
brachialis.
- It enters the nutrient canal near the insertion of coraco-brachialis.
5. Muscular branches: Supply biceps, brachialis and coraco-brachialis.
6. Terminal branches: radial and ulnar arteries.

- Surface anatomy: it is represented by a vertical line drawn between two

points: A point at the posterior fold of the axilla where the pulsation of the
axillary artery can be felt. The other point is midway between the two
epicondyles of the humerus medial to the tendon of the biceps.
Anastomosis around the elbow Joint
It is an anastomosis between the brachial artery, above the elbow joint, and the
radial and ulnar arteries, below the joint. It is described in relation to the medial
and lateral epicondyles (Fig. 78).
- Anastomosis around the medial epicondyle:
A. On its back:
1. Superior ulnar collateral and posterior branch of inferior ulnar
collateral (from
The brachial artery).
2. Posterior ulnar recurrent artery (from the ulnar artery).
B. On its front:
1. Anterior branch of inferior ulnar collateral artery (from brachial
artery).
2. Anterior ulnar recurrent artery (from ulnar artery).
 Arm 93

 Arm 94

- Anastomosis around the lateral epicondyle
A. On its back:
1. Posterior descending branch (middle collateral) of profunda brachii
artery.
2. Posterior interosseous recurrent artery (arises from posterior
interosseous artery, a branch from ulnar artery)

B. On its front:
1.Anterior descending branch (Radial collateral artery) of profunda
brachii artery.
2. Radial recurrent artery (from radial artery).

- Transverse anastomosis: it lies above the olecranon fossa between

the inferior ulnar collateral and the posterior descending branch of
profunda brachii.

NERVES OF THE ARM

The nerves of the arm include the following:
A. Musculocutaneous nerve
B. Ulnar
C. Median
D. Radial

A. Musculo-cutaneous nerve
- Origin: it arises in the axilla from the lateral cord of brachial plexus, (C5, 6,
7)
- Course (Figs. 79, 80, 81, 82):
 It descends lateral to the third part of axillary artery and uppermost part
of brachial artery.

 Then it pierces coraco-brachialis and descends obliquely between biceps

and brachialis muscles and supplies these three muscles.

 About one inch above the elbow it pierces the deep fascia at the lateral
border of the biceps tendon to become superficial and is called the lateral
cutaneous nerve of forearm which divides into anterior and posterior
branches which supply the lateral side of the forearm as well as the ball of
the thumb.
 Arm 95

Axillary
Fig. 81: Nerves & brachial artery in the arm
vein
(Medial view)


Subscapularis


Latissimus
dorsi
Aponeurosis

Fig. 82: Nerves Fig. 83: Ulnar 

of the arm nerve
(Anterior view) (Back of arm)

Medial
epicondyle

Ulnar nerve

Post. Ulnar
recurrent A.
Olecranon

Flexor capi
ulnaris muscle



Radial nerve
 Arm 96


B. Ulnar nerve


- Origin (Fig. 79): It arises in the axilla from the medial cord of brachial
plexus. It arises mainly from C8 and T1, but fibers from C7 reach the
ulnar nerve by one of two ways:
 A root from the lateral cord which joins ulnar nerve in the axilla.
 A root from median nerve which joins ulnar nerve in the forearm.

- Course and Relations (Figs. 79, 81, 82, 83):

 In the axilla: it descends on the medial side of the third part of
axillary artery lying with the medial cutaneous nerve of forearm
between the artery and the axillary vein.
 In the arm:
- In the upper half of the arm: it descends on the medial side of upper
half of brachial artery, lying with medial cutaneous nerve of forearm
between the artery and the basilic vein.
- At the middle of the arm: opposite the insertion of coraco-brachialis,
it leaves the brachial artery and passes backwards piercing the
medial intermuscular septum (with superior ulnar collateral artery) to
reach the posterior compartment of the arm.
- In the lower half of the arm: It descends in the posterior
compartment of the arm, lying on the medial head of triceps.

 At the elbow:
- It descends behind the medial epicondyle grooving it (shallow
groove).
- Then it enters the forearm by passing between the two head of flexor
carpi ulnaris muscle, accompanied by posterior ulnar recurrent artery.
- Branches: ulnar nerve gives no branches in the axilla and the arm.

C. Median nerve

- Origin: It arises in the axilla by two roots; medial and lateral roots arising
from the medial and the lateral cord of the brachial plexus. The medial
root crosses in front of the third part of axillary artery to join the lateral
root to form together the median nerve trunk (C5, 6, 7, 8 and T1) on the
lateral side of the artery.
- Course and Relations:
 In the axilla: it descends lateral to the third part of axillary artery.
 Arm 97

 Arm 98

In the arm:
- In the upper half of the arm: the median nerve descends lateral to
the upper half of brachial artery.
- At the middle of the arm opposite the insertion of coraco-brachialis,
the median nerve crosses the brachial artery from the lateral to
medial side of the artery, either in front or behind the artery.
- In the lower half of the arm: It descends medial to the lower half of
brachial artery lying on brachialis muscle (which separates the
artery and the nerve from the lower part of the shaft of humerus).
 At the elbow joint:
- It lies medial to the brachial artery which separates it from biceps
tendon.
- It lies in front of brachialis, which separates it from elbow joint
- It lies behind the bicipital aponeurosis which separates it from
median cubital vein.
 The median nerve leaves the arm by passing into the cubital fossa of
the forearm.
- Branches: the median nerve gives no branches in the axilla and the arm.

D. Radial nerve
- Origin (Fig. 84): in the axilla as the larger of the two terminal branches of
the posterior cord of brachial plexus (C5, 6, 7, 8 and T1).

- Course and Relations (Figs. 84, 85, 86):

 In the axilla: it descends on the posterior wall of the axilla behind
the third part of the axillary artery.
 In the arm:
- In the upper third: it passes downwards and laterally behind the
proximal part of the brachial artery separating it from long head of
triceps.
- In the middle third: it leaves the front of the arm by passing
backwards between the long and medial heads of triceps to reach
the spiral groove, where it runs downwards and laterally between
lateral and medial heads of triceps accompanied by profunda brachii
vessels.
- In the lower third: it pierces the lateral intermuscular septum
accompanied by the radial collateral artery (one of the two terminal
branches of profunda) to reach the front of the arm again where it
descends between brachialis and brachio-radialis down to the front
of the lateral epicondyle.
 In front of the lateral epicondyle: it gives an important deep
branch called posterior interosseous nerve (mainly muscular).Then the
radial nerve itself continues as the superficial radial nerve (mainly
cutaneous).
 Arm 99

- Branches of radial nerve:
 In the axilla (Fig. 57):
- Muscular: to supply the long and medial heads of triceps.
- Cutaneous: posterior cutaneous nerve of the arm (posterior
cutaneous brachial nerve), which supplies the skin on the back of
the arm from the deltoid tuberosity down to the elbow.
 In the spiral groove (Figs. 77, 85)
- Muscular: to the lateral and medial heads of triceps and anconeus.
- Cutaneous:
1. Lower lateral cutaneous nerve of the arm: it supplies the skin on
the lateral surface of the arm from the deltoid tuberosity down to
the elbow.
2. Posterior cutaneous nerve of the forearm: it descends behind the
lateral epicondyle to supply the skin of the middle of the back of
the forearm down to the wrist.
 In the lower third of the arm (in the groove between brachialis and
brachio-radialis) it gives muscular branches to supply the brachio-
radialis and extensor carpi radialis longus as well as the small lateral
part of the brachialis.
 Terminal branches in front of the lateral epicondyle (Fig. 86):
the radial nerve ends by giving posterior interosseous branch (deep
branch of radial nerve) then continues as superficial radial nerve.

Fig. 86: Terminal branches

of radial nerve in cubital
fossa (Anterior view)
 Arm 100

Formative assessment

I. Explain the following: fracture surgical neck of humerus may result

in flat shoulder.

II. Choose the correct answer:

The continuation of musculocutaneous nerve is
a. Posterior cutaneous nerve of forearm
b. Medial cutaneous nerve of forearm
c. Lateral cutaneous nerve of forearm
d. Medial cutaneous nerve of arm

 Forearm 101

CHAPTER 7

ILOs:
By the end of the lectures, the student should be able to:
 Define the site of the cubital fossa.
 Enumerate the boundaries and contents of the cubital fossa.
 Describe the attachment, nerve supply and action of the muscles of the
flexor compartment of forearm.
 Explain the relation of the median nerve to pronator teres and flexor
digitorum superficialis muscles and the ulnar nerve to flexor carpi ulnaris.
 Describe the attachment, nerve supply and action of the muscles of the
extensor compartment of forearm.
 Explain the relation of the posterior interosseus nerve to supinator.
 Outline the boundaries & contents of the anatomical snuff box.
 Discuss the origin, course and relation, branches and surface anatomy of
the ulnar and radial arteries.
 Recognize the course, branches and relation of the ulnar, median,
superficial radial, posterior interosseous nerves.
 Discuss the attachment and relations of the flexor retinaculum.
 Define the boundaries and contents of the carpal tunnel.
 Describe the attachment and relations of the extensor retinaculum.

FOREARM
Deep fascia of the forearm
(Antebrachial fascia)
The deep fascia of the forearm is called antebrachial fascia and it is thicker on
the posterior than on the anterior surface of the forearm. It gives partial origin to
the muscles of the forearm both in front and behind.

- Sites of thickening of the antebrachial fascia:

1. It is strengthened above by the bicipital aponeurosis.
2. Along the posterior border of the ulna, the deep fascia forms a strong
aponeurosis which gives origin to the following muscles:
a. Flexor carpi ulnaris
b. Extensor carpi ulnaris
c. Flexor digitorum profundus
3. The deep fascia is thickened in the region of the wrist, where it forms
two bands, one in front called flexor retinaculum and one behind
called extensor retinaculum.
 Forearm 102

FRONT OF THE FOREARM
CUBITAL FOSSA
- Definition and Site: it is an inverted triangular hollow in fron of the
elbow joint. It occupies the upper one third of the front of the forearm.

- Boundaries (Figs. 87, 88, 89): it has apex, base, medial and lateral
boundaries as well as roof and floor:
 Base: is directed upwards. It is an imaginary line passing between the
two epicondyles of the humerus.
 Lateral boundary: is formed by the medial margin of the brachio-
radialis muscle.
 Medial boundary: is formed by the lateral margin of the pronator teres
muscle.
 Apex: is formed by the meeting of brachio-radialis and pronator teres.
 Floor: Is formed by the lower part of brachialis, medially and the anterior
part of the supinator, laterally.
 Roof: is formed by:
a. Skin and superficial fascia which contains:
1. Parts of cephalic and basilic veins and the median cubital vein,
connecting them.
2. Anterior branches of both lateral and medial cutaneous nerves of
the forearm.
3. Supra-trochlear lymph nodes.
b. Deep fascia which is reinforced by the bicipital aponeurosis, passing
obliquely downwards and medially.
- Contents (Fig. 88): from medial to lateral:
1) Median nerve: it leaves the cubital fossa by passing between the two
heads of pronator teres muscle.
2) Termination of the brachial artery and the beginning of ulnar and radial
arteries:
 The brachial artery lies in the middle of the cubital fossa separated
from the median cubital vein by the bicipital aponeurosis. The
brachialis muscle separates the artery from the front of the elbow
joint.
 The ulnar artery leaves the cubital fossa by passing deep to the two
heads of pronator teres.
 The radial artery leaves the cubital fossa by descending through the
apex overlapped by brachio-radialis.
3) Tendon of biceps: inserted into the posterior part of radial tuberosity.
4) Radial nerve and the beginning of its posterior interosseous branch,
which leaves the cubital fossa by piercing the supinator muscle.
N.B. Supra-trochlear lymph nodes (one or two in number): lie in the upper and
medial part of the roof of the cubital fossa (lying on the deep fascia above the medial
epicondyle on the medial side of the basilic vein).
 Forearm 103


Biceps
brachii
Bicips Brachial
Brachialis brachii artery

Brachialis Median
Brachioradialis nerve
Medial
epicondyle Radial nerve Medial
Posterior epicondyle

Brachio- Pronator teres Interosseous N

Biceps
radialis
Bicipital Superficial tendon
aponeurosis radial nerve
Ulnar
Flexor carpi Supinator artery
radials
Radial artery
Palmaris longus

Flexor carpi
ulnaris Flexor
digitorum
superficialis

Fig. 87: Boundaries of cubital fossa Fig. 88: Contents of cubital fossa

(Anterior view) (Anterior view) 

Fascia covering Medial cutaneous

biceps brachii nerve of forearm

Cephalic vein Basilic vein

Lateral cutaneous Median cubital vein

nerve of forearm

Perforating vein
Bicipital aponeurosis
Median vein of
forearm

Fig. 89: Roof of the cubital fossa (Anterior view)


 Forearm 104

MUSCLES OF THE FRONT OF THE FOREARM

These are the flexors of the wrist and digits and the pronators of the forearm.
They are arranged in two groups:

A. Superficial group: consists of five muscles arising by a common

tendon from the front of the medial epicondyle. They are arranged in
two layers:
 Four superficial muscles, arranged from lateral to medial as follows:
1. Pronator teres
2. Flexor carpi radialis
3. Palmaris longus
4. Flexor carpi ulnaris
 One deep muscles: the flexor digitorum superficialis, which lies
deep to the above mentioned four muscles.

B. Deep group: consists of three muscles arranged in two layers:

 Two superficial muscles:
1. Flexor pollicis longus (laterally)
2. Flexor digitorum profundus (medially)
 One deep muscle: the pronator quadratus muscle. It is the deepest
one, running horizontally in front of the lower parts of radius and
ulna.

A. Superficial group of muscles (Fig.90):

 Common flexor origin: from the anterior surface of medial
epicondyle of the humerus (the common flexor origin).
 Common nerve supply: from median nerve (except flexor carpi
ulnaris which is supplied by ulnar nerve).
 Common action:
1. Flexion of the wrist (except pronator teres).
2. Weak flexion of the elbow.

1. Pronator Teres Muscle (Fig. 91):

- Origin: by two heads:
1. Humeral head: is the larger and the more superficial head. It arises
from:
 Common flexor origin.
 Lower part of medial supracondylar ridge of the humerus.
 Forearm 105



Fig. 90: Muscles of front of forearm

(Superficial group)

Pronator teres Flexor carpi

Flexor carpi
radialis
ulnaris

Fig. 91  Fig. 92  Fig. 93


 Forearm 106

2. Ulnar head: is the smaller and deeper head. It arises from the
medial side of coronoid process of ulna.
- Insertion: the muscle passes obliquely across the upper half of the
front of the forearm to be inserted into a rough impression (pronator
tuberosity) on the middle of the lateral surface of the shaft of radius
(point of maximum lateral convexity of the radius).
- Action:
1. Powerful pronation of the forearm (at radio-ulnar joints).
2. Weak flexion of the elbow.
- Relations: median nerve enters the forearm between its two heads
while ulnar artery passes deep to the two heads of the muscle.

2. Flexor Carpi Radialis Muscle (Fig. 92):

- Origin: common flexor origin.
- Insertion: the tendon passes through the lateral part of the flexor
retinaculum, in a special compartment, occupying a groove on the
trapezium bone. It is inserted into the palmar surfaces of the bases of
the 2nd and 3rd metacarpal bone.
- Action: in addition to the common action, it abducts the hand (acting
with extensor carpi radialis longus and brevis).

3. Palmaris Longus Muscle (Fig. 90):

It is a slender muscle with very long tendon. It may be absent in one or
both sides.
- Origin: common flexor origin.
- Insertion: it passes superficial to the flexor retinaculum to be
inserted into:
 Distal part of flexor retinaculum.
 Apex of palmar aponeurosis.
- Action: in addition to the common action, it makes the palmar
aponeurosis tense to give more protection to the structures in the palm
of the hand.
4. Flexor Carpi ulnaris Muscle (Fig. 93):
It lies along the medial side of the forearm.
- Origin: it arises by two heads:
 Humeral head: is small and arises from the common flexor origin.
 Ulnar head: from the medial margin of olecranon process and from the
upper two thirds of posterior border of ulna by an aponeurosis.
- Insertion: its tendon is inserted into the pisiform bone. The tendon is then
prolonged to the hook of hamate and base of 5th metacarpal bone as piso-
hamate and piso-metacarpal ligaments, respectively.
 Forearm 107

- Action: in addition to the common action, it adducts the hand (acting with
extensor carpi ulnaris muscle).

- Relations: between its two heads, the ulnar nerve passes downwards to
reach the front of the forearm and the posterior ulnar recurrent artery
passes upwards to reach the back of the medial epicondyle.

5. Flexor Digitorum Superficialis (Sublimis) Muscle (Fig. 90):

- Origin: it arises by two heads:
 Humero-ulnar head: from the common flexor origin and from the
medial side of the coronoid process of the ulna.
 Radial head: is a thin sheet of muscle arising from the anterior
oblique line of radius.
- Insertion: by four tendons which pass deep to the flexor retinaculum
across the carpal tunnel being arranged in pairs: The superficial pair
going to the middle and ring fingers and the deep pair to the index
and little fingers. On reaching the proximal phalanges of the medial
four fingers, each tendon divides into two slips (to allow passage of
the corresponding underlying tendon of flexor digitorum profundus)
and finally the two slips are inserted into the sides of the shaft of the
middle phalanx.
- Action: in addition to the common action, it flexes metacarpo-
phalangeal and proximal inter-phalangeal joints of the medial four
fingers.
- Relations: the median nerve passes through the gap between the
two heads of the muscle where it descends adherent to its deep surface
between it and the lateral half of flexor digitorum profundus.

B. Deep group of muscles

They have a common nerve supply which is the anterior interosseous branch
of the median nerve, except the medial half of flexor digitorum profundus
which is supplied by the ulnar nerve.

1. Flexor digitorum profundus muscle (Figs 94, 95):

- Origin: it is situated on the ulnar (medial) side of the forearm and
arises from:
 Upper ¾ of anterior and medial surfaces of shaft of ulna.
 Medial half of the anterior surface of the interosseous membrane.
- Insertion: the muscle ends in four tendons which run through the
carpal tunnel deep to the flexor retinaculum behind the tendons of flexor
digitorum superficialis and are arranged in one row. Opposite the proximal
phalanges of the medial four fingers, each tendon passes between the
 Forearm 108

two slips of the corresponding overlying tendon of flexor digitorum
superficialis (Fig. 95) to reach their insertion into the palmar surface of the
base of distal phalanx..
- Action:
 Flexes all joints of the medial four fingers.
 Flexes the wrist.

2. Flexor pollicis longus muscle (Fig.94):

- Origin: it is situated on the radial (lateral) side of the forearm and arises
from:
 Upper two thirds of anterior surface of the shaft of radius below the
anterior oblique line.
 The adjacent part of anterior surface of interosseous membrane.

- Insertion: by a tendon which passes behind (deep to) the lateral part of
the flexor retinaculum through the carpal tunnel to become inserted
into the palmar surface of the base of the distal phalanx of the thumb.

- Action:
 Flexes all joints of the thumb.
 Flexes the wrist.

N.B. The 8 tendons of flexor digitorum superficialis and profundus are surrounded
by a common flexor synovial sheath (Ulnar bursa). The tendon of flexor
pollicis longus is surrounded by its synovial sheath (Radial bursa).

3. Pronator quadratus muscle (Fig. 94):

It is a quadrangular muscle deeply situated in the front of the lower part of
the forearm, beneath the lower part of both flexor digitorum profundus and
flexor pollicis longus.
- Origin: it arises from the oblique ridge on the lower quarter of the anterior
surface of the shaft of the ulna.

- Insertion: The fibers pass laterally and slightly downwards in front of the
lower part of interosseous membrane to be inserted into the lower
quarter of the anterior and medial surfaces of the shaft of the radius.
- Action: it pronates the forearm at the radio-ulnar joints.
 Forearm 109

 Forearm 110

BACK OF THE FOREARM

Muscles of the back of the forearm

These are the extensors of the wrist and digits. The tendons of all those
muscles, apart from that of the brachioradialis, pass deep to the extensor
retinaculum to reach their insertion. They are arranged in two groups:
A. Superficial group (7 muscles) (Fig. 96): they are arranged from
lateral to medial as follows:
1. Brachio-radialis
2. Extensor carpi radialis longus
3. Extensor carpi radialis brevis
4. Extensor digitorum
5. Extensor digiti minimi
6. Extensor carpi ulnaris
7. Anconeus

B. Deep Group (5 muscles) (Fig. 97): they are arranged from above
downwards as follows:
1. Supinator
2. Abductor pollicis longus
3. Extensor pollicis brevis
4. Extensor pollicis longus
5. Extensor indicis

N.B. The lower part of the three pollicis muscles (in the deep group) become superficial
at the lower part of the forearm and their tendons form the boundaries of the
anatomical snuff-box.
 Forearm 111


(Posterior view) (Anterior view)

Anconeus Brachioradialis
Brachio-
Extensor carpi radialis
radialis longus
Extensor
Extensor Extensor carpi carpi radialis
digiti minimi radialis brevis longus

Extensor Extensor
Extensor digitorum carpi radialis
carpi ulnaris brevis

Abductor
pollicis longus

Extensor
pollicis brevis

Fig. 96: Muscles of

the back of forearm
(Superficial group) 


Lateral epicondyle

Anconeus

Supinator

Back of ulna

Abductor pollicis longus

Extensor pollicis brevis

Extensor pollicis longus

Extensor indicis

(Posterior view)

Fig. 97: Muscles of the

back of forearm
(Deep group)

 Forearm 112

A. Superficial group of muscles
They have a common extensor origin from the anterior and lateral surfaces of
the lateral epicondyle of the humerus, except brachioradialis, extensor carpi
radialis logus and anconeus

1. Brachioradialis
It is the most lateral muscle of this group extending from the lower part of the
shaft of humerus to lower end of the radius (Fig. 98).
- Origin:
1. Upper two thirds of lateral supracondylar ridge of the humerus.
2. Front of lateral intermuscular septum of the arm.
- Insertion: by a long flat tendon into the lateral side of lower end of radius
immediately above the base of the styloid process.
- Nerve supply: from the radial nerve while it lies on the lateral side of the
arm.
- Action:
1. It puts the forearm in midprone position; a position midway between
pronation and supination.
2. It flexes the elbow joint.

2. Extensor Carpi Radialis Longus

It lies next to brachio-radialis and it is partly covered by it (Fig. 98).
- Origin:
1. Lower one third of lateral supracondylar ridge of the humerus.
2. Front of lateral intermuscular septum of the arm.
- Insertion: by a long flat tendon into the dorsal surface of the base of 2nd
metacarpal bone.
- Nerve supply: from the radial nerve while it lies on the lateral side of the
arm.
- Action:
1. It extends and abducts the wrist.
2. Acting with the extenor carpi ulnaris, the two muscles produce pure
extension of the wrist.
3. Acting with the flexor carpi radialis, the two muscles produce abduction of
the wrist.
 Forearm 113

3. Extensor Carpi Radialis Brevis
It is shorter than the extensor carpi raqdialis longus and it lies deep to it
throughout its course (Fig. 98).
- Origin: from the common extensor origin.
- Insertion: by a flat tendon into the dorsal surface of the base of the 3rd
metacarpal bone.
- Nerve supply: by a branch from the posterior interosseous nerve, in front
of the forearm, before the nerve pierces the supinator muscle.
- Action: the same action as that of the extensor carpi radialis longus.
N.B. At the lower part of the lateral border of the forearm, the tendons of the extensor
carpi radialis longus and brevis are crossed superficially by the tendons of the abductor
pollicis longus and extensor pollicis brevis, of the deep group mucles of back of forearm.

4. Extensor Digitorum
It lies medial to the two extensor carpi radialis muscles (Fig. 98).
- Origin: from the common extensor origin.
- Insertion: it divides below into four tendons, which pass deep to the
extensor retinaculum to reach the dorsum of the hand. The four tendons
diverge towards the medial four fingers. On reaching the dorsal surface of the
proximal phalanges of these fingers, each tendon joins the extensor expansion
of the corresponding finger (see extensor expansion).
- Action:
1. Extends the metacarpo-phalangeal and interphalangeal joints of the
medial four fingers.
2. Assists in extension of the wrist.

* Extensor expansion
- Definition: it is a strong triangular fibrous sheet with its base directed
proximally and its apex directed distally. It covers the dorsum of the
proximal phalanx of each of the medial four fingers. It receives the extensor
tendons of the digits and tendons of lumbricals and interossei (Fig. 99).
- Structure:
Each expansion consists of:
 A thick middle part formed by:
1. One of the four tendons of the extensor digitorum.
 Forearm 114

2. In addition, that of the little finger is joined by the tendon of
extensor digiti minimi, and that of the index is joined by the tendon
of extensor indicis.
 Two margins formed by the tendons of lumbricals and interossei.
- Insertion: as it approaches the proximal interphalangeal joint, the expansion
divides into an intermediate part and two collateral parts. The intermediate
(central) part is attached to the base of the middle phalanx, whiles the two
collateral parts unit on the dorsum of the middle phalanx and are attached to
the base of the terminal phalanx.

5. Extensor Digiti Minimi

- Origin (Fig. 98): from the common extensor origin.
- Insertion: by a tendon which runs through a separate compartment deep to
the extensor retinaculum behind the inferior radio-ulnar joint. Finally its tendon
joins that of the extensor digitorum in the middle part of the extensor expansion
of the little finger (see extensor expansion).

- Action:
1. Extends the little finger (mainly the metacarpo-phalangeal joint).
2. Assists in extension of the wrist.

6. Extensor Carpi Ulnaris

- Origin (Fig. 98):
1. From the common extensor origin.
2. The upper two thirds of the posterior border of the ulna by an aponeurosis
(in common with flexor carpi ulnaris).

- Insertion: by a tendon which passes through a separate compartment deep

to the extensor retinaculum where the tendon runs in a groove on the back of
the lower end of the ulna (between the head and the styloid process). The
tendon is inserted into the dorsal aspect of the base of the 5th meta-carpal
bone.

- Action:
1. Extends the wrist.
2. Adducts the wrist (acting with flexor carpi ulnaris).
 Forearm 115


Brachioradialis

(Posterior view)




Fig. 98: Attachments of the muscles of back of forearm
(Superficial group)
 Forearm 116


7. Anconeus:
It is a small triangular muscle lying on the back of the elbow joint and
appears as the continuation of triceps muscle (Fig. 97).

- Origin: by a separate tendon from the back of lateral epicondyle of the

humerus.

- Insertion: into the lateral side and the triangular area on the back of the
olecranon process of ulna.

- Action: assists triceps in extending the elbow.

N.B.
Anconeus may be considered as the fourth head of triceps because:
1. Its nerve supply arises from the radial nerve at the same level at which medial
and lateral heads of triceps are supplied (in the spiral groove).
2. It assists triceps in extending the elbow.
3. It is covered by an expansion from the tendon of insertion of triceps.
 Forearm 117

Deep Group (Deep Extensors)
They have a common nerve supply from the posterior interosseous branch of the
radial nerve. They are arranged from above downwards as follows: Supinator,
abductor pollicis longus, extensor pollicis longus, extensor pollicis brevis and
extensor indicis.

1. Supinator
- Origin (Fig. 100):
It surrounds the upper third of the shaft of the radius.
1. Supinator crest and fossa of the ulna.
2. Lateral epicondyle of the humerus, lateral collateral ligament of the elbow
and the annular ligament.
- Insertion:
The fibers pass downwards, backwards and laterally to be inserted into the
posterior, lateral and anterior aspects of the upper third of radius above the
anterior and posterior oblique lines. The insertion reaches as low as the
insertion of the pronator teres.
- Action: it supinates the forearm, at radio-ulnar joints.
- Relations:
1. The supinator muscle is pierced by the posterior interosseous nerve (Fig.
100), which curves around the upper part of the radius inside the muscle
substance, splitting it into two layers (superficial and deep).
2. The supinator muscle forms part of the floor of the cubital fossa.

2. Abductor Pollicis Longus

- Origin (Fig. 101):
1. Posterior surface of shaft of ulna below the insertion of anconeus.
2. The back of the interosseous membrane.
3. The posterior surface of radius just below the insertion of supinator.
- Insertion: the muscle passes downwards and laterally and ends in a tendon
which is inserted into the lateral side of the base of the first metacarpal bone
(of the thumb).
- Action:
1. It abducts the thumb at the carpo-metacarpal joint.
2. It helps to abduct the wrist.
3. It can flex the wrist; an important function when both of the median and
ulnar nerves become paralyzed.
 Forearm 118

3. Extensor Pollicis Brevis
It runs closely below and medial to abductor pollicis longus (Fig. 101).
- Origin: from the posterior surface of the shaft of the radius below the origin
of abductor pollicis longus and from the back of the interosseous membrane.
- Insertion: the muscle runs downwards and laterally and ends in a tendon
which descends on the back of the 1st metacarpal bone to be inserted into the
dorsal surface of the base of proximal phalanx of the thumb.
- Action: it extends the metacarpo-phalangeal and carpo-metacarpal joints of
the thumb.

4. Extensor Pollicis Longus

It is longer and larger than the extensor Pollicis Brevis and lies on the ulna
below the abductor policis longus (Fig. 101).
- Origin: from the middle third of the posterior surface of the shaft of ulna
below the origin of abductor pollicis longus and from the back of the
interosseous membrane.
- Insertion: it ends in a tendon, which passes through a separate
compartment deep to the extensor retinaculum. Then, it crosses obliquely
superficial to the tendons of extensor carpi radialis longus and brevis to reach
the back of the thumb where it is inserted into the dorsal surface of the base
of its distal phalanx.
- Action: it extends all joints of the thumb.
5. Extensor Indicis
- Origin (Fig. 101):
1. The posterior surface of the shaft of ulna below the origin of extensor
pollicis longus.
2. The interosseous membrane.
- Insertion: by a tendon which passes under cover of extensor retinaculum in
the same compartment transmitting the tendons of extensor digitorum.
Opposite the head of the 2nd metacarpal bone, it joins the tendon of extensor
digitorum going to the index finger forming middle part of the extensor
expansion of the index (see extensor expansion).
- Action:
1. It extends the index finger (mainly the metacarpo-phalangeal joint).
2. It helps in extending the wrist.
 Forearm 119


Anterior view

Radius

Ulna

 
Fig.100: Attachments of the supinator M. & its relation to posterior interosseous nerve



 

Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus Extensor indicis

Fig. 101: Attachments of the Muscles of the back of the forearm (Deep Group)
 Forearm 120

Anatomical Snuff-Box
- Position and boundaries (Figs. 102, 103):
It is triangular hollow located at the lateral part of the dorsum of the wrist
and it becomes clearly visible when the thumb is extended. It has the
following boundaries:
 Medially: tendon of extensor pollicis longus.
 Laterally: tendons of abductor pollicis longus and extensor pollicis brevis.
-Roof:
 Skin.
 Superficial fascia containing beginning of cephalic vein and digital branches
of the superficial radial nerve.
 Deep fascia.
- Floor: it is formed by Styloid process of radius and two carpal bones;
scaphoid (proximally) and trapezium (distally).
- Contents:
 Radial artery as it crosses the dorsum of the hand (its pulsations can be
felt in the snuff-box).
 Tendons of extensor carpi radialis longus and brevis, crossing the floor.
 Forearm 121


Fig. 102: Anatomical

Snuff Box
(Lateral View)

Cephalic vein (cut) 

Terminal branches of
radial nerve (cut)

Fig. 103: Floor of

Anatomical Snuff Box

(Lateral view)
 Forearm 122

ARTERIES OF THE FOREARM
Radial Artery
- Beginning: it begins in the cubital fossa, 1 cm below the elbow joint, at the
level of neck of radius as the smaller of the two terminal branches of the
brachial artery.
- Course and end (Figs. 104, 105, 106):
 In the forearm: it passes downwards and laterally in the lateral part of
the front of the forearm to reach the wrist.
 At the wrist: it winds backwards round the lateral side of the wrist
passing through the anatomical snuff-box to reach the dorsum of the
hand.
- Relations:
 In the forearm:
* Anteriorly:
 In the upper part: the artery is overlapped by the fleshy belly of
the brachioradialis.
 In the lower part: the artery becomes superficial being covered
only by skin, superficial and deep fasciae where its pulsations
can be felt between the tendon of flexor carpi radialis (medially)
and tendon of brachioradialis (laterally).
* Posteriorly: the radial artery lies on the muscles attached to the
front of radius. Thus, from above downwards, it lies successively
on:
 Biceps tendon
 Supinator
 Insertion of pronator teres
 Origin of radial head of flexor digitorum superficialis
 Flexor pollicis longus
 Pronator quadratus
 Lower end of radius, directly on the bone (a suitable site to
check the pulse of the artery against the bone).
* Laterally:
 Brachio-radialis (its fleshy belly lies lateral to the upper part of
the artery, while its tendon lies lateral to the lower part of the
artery).
 Superficial radial nerve: it descends closely lateral to the artery,
in the middle third of the forearm.

N.B. The nerve is separated from the artery by a slight interval, in

the upper third of the forearm, while in its lower third, the
nerve leaves the artery by curving backwards round the
lateral margin of the forearm undercover of brachio-radialis
tendon to reach its back.
 Forearm 123

 Pronator
Radial artery teres

Brachio- Flexor carpi

radialis radialis

Flexor
digitorum
superficialis

Radial artery
Flexor carpi
Flexor ulnaris
digitorum
superficialis
Palmaris
Flexor longus
pollicis
longus



Median nerve

 
Fig.104: Course & relations of the radial
artery in the forearm (Anterior view)
 Fig. 105: Front view of forearm
showing deep relations of the radial
Flexor pollicis longus artery with its branches
Flexor digitorum profundus

Pronator quadratus

Lower end of radial artery

lying on lower end of radius

Anterior carpal br. of radial a

Superficial palmer
Br of radial a.
Abductor pollicis
longus
Extensor pollicis
brevis

Fig. 106: Deep relations & branches of the
lower part of radial artery in the front of
forearm
 Forearm 124


* Medially:
 In the upper third: pronator teres muscle.
 In the lower two thirds: tendon of flexor carpi radialis muscle.

 At the wrist: Radial artery turns backwards around the lateral side of the
wrist to run on the floor of the anatomical snuff-box reaching the dorsum of
the hand.

N.B. The radial artery is accompanied by two venae comitantes.

- Branches: from above downwards it gives the following branches:

1. Radial recurrent artery: arises near the origin of radial artery and
ascends to anastomose with radial collateral artery (the anterior terminal
branch of profunda brachii artery) in front of lateral epicondyle.
2. Muscular branches: to supply muscles on the radial side of the
forearm.
3. Anterior carpal artery: runs medially across the front of the carpus
deep to the flexor tendons to anastomose with anterior carpal branch of
the ulnar artery together forming the anterior carpal arch.
4. Superficial palmar artery: arises from the radial artery at the wrist
before it turns backwards. It descends through the thenar muscles
(supplying them) and ends by anastomosing with the terminal part of
ulnar artery, completing the superficial palmar arch.

 Surface anatomy of the radial aretry:

a line extending between two points:
*Point 1: midway between the two epicondyles of the humerus, medial to the
tendon of the biceps.
*Point 2: at the front of the lower end of radius where the pulsation of the
artery is felt.
 The distal portion of the artery is indicated by continuing this line
around the radial side of the wrist to the proximal end of the first
metacarpal interosseous space.
 Forearm 125

Ulnar Artery
- Beginning: in the cubital fossa, 1 cm below the elbow joint, at the level of
neck of radius as the larger of the two terminal branches of brachial
artery.
- Course (Figs. 107, 108, 109):
 In the upper third of forearm: it runs obliquely downwards and
medially to reach the medial side of the front of the forearm.
 In the lower two thirds of forearm: it descends vertically along the
medial side of the front of the forearm to reach the wrist.
 At the wrist: it descends superficial to the flexor retinaculum lateral
to ulnar nerve and the pisiform bone and medial to the hook of
hamate. It ends in the hand by becoming the superficial palmar arch.
N.B. Sometimes, the ulnar artery and nerve are covered by a
superficial layer of the flexor retinaculum.
The ulnar artery is accompanied by two venae comitantes.
- Relations:
* Posteriorly: from above downwards, ulnar artery lies on:
1. Brachialis tendon, in the cubital fossa.
2. Flexor digitorum profundus muscle (medial 1/2).
3. Flexor retinaculum, at the wrist.

* Anteriorly:
 In the upper third of the forearm, the ulnar artery passes downwards
and medially deep to:
1. The two heads of pronator teres.
2. Flexor carpi radialis.
3. Palmaris longus.
4. Flexor digitorum superficialis.

 In the middle third of the forearm, the ulnar artery (and nerve) is
overlapped by flexor carpi ulnaris muscle.
 In the lower third of the forearm (above the wrist), the ulnar
artery becomes superficial (covered only by skin, superficial and deep
fascia) between the tendon of flexor carpi ulnaris (medially) and
tendons of flexor digitorum superficialis (laterally).

* Medially: the ulnar nerve descends medial to ulnar artery.

 At the elbow, the artery is separated from the nerve by a gap.
 In the upper third of the forearm, ulnar artery runs obliquely downwards
and medially approaching the nerve.
 In the lower two thirds of the forearm, the nerve lies closely medial to
the ulnar artery.
 Forearm 126

- Branches:
 Near the elbow:
1. Anterior ulnar recurrent artery: it ascends to anastomose with the
anterior branch of inferior ulnar collateral artery in front of the medial
epicondyle of humerus. (anastomosis around the elbow).
2. Posterior ulnar recurrent artery: it ascends between the two heads of
flexor carpi ulnaris to reach the back of medial epicondyle where it
anastomoses with superior ulnar collateral artery.
3. Common Interosseous artery: is a short trunk which arises about one
inch below the beginning of ulnar artery. It descends backwards to reach
the upper margin of the interosseous membrane, where it divides into
anterior and posterior interosseous arteries:
a) The anterior interosseous artery (the larger branch):
- Course:
 It descends on the anterior surface of interosseous membrane
accompanied by anterior interosseous branch of median nerve
between flexor pollicis longus (laterally) and flexor digitorum
profundus (medially).
 At the upper border of pronator quadratus it pierces the interosseous
membrane to reach back of forearm where it anastomoses with the
termination of posterior interosseous artery.
 Then it descends accompanied by posterior interosseous nerve on
the back of the wrist deep to the extensor retinaculum in the same
compartment containing tendons of extensor indicis and extensor
digitorum (fourth compartment).
 It ends by joining the posterior carpal arch.
- Branches:
 Near its beginning, it gives median artery which accompanies and
supplies median nerve (vasa nervosa).
 Muscular branches.
 Nutrient arteries of both radius and ulna.
 At the upper border of pronator quadratus (before piercing the
interosseous membrane), it gives a descending branch which descends
deep to pronator quadratus to join the anterior carpal arch.
b) Posterior interosseous artery (smaller than the anterior).
- Course:
 It passes backwards above the interosseous membrane to reach
back of forearm where it descends between the superficial and
deep muscles of the back of forearm accompanied by posterior
interosseous branch of radial nerve.
 In the lower part of the forearm, it becomes small and ends by
anastomosing with anterior interosseous artery.
 Forearm 127
 Brachial artery
Brachialis
Median nerve

Anterior ulnar recurrent a.

Flexor carpi ulnaris (cut)

Supinator Ulnar artery

Posterior ulnar recurrent a.

Common interosseous a.
Deep head of Pronator teres (cut)
separating ulnar a. from median n.

Anterior interosseous a. & N.

Flexor digitorum profundus

Flexor digitorum superficialis (cut)

Ulnar artery & nerve

Flexor pollicis longus

Anterior carpal
br. of ulnar a.

Pisiform bone

Posterior ulnar
 recurrent
Anterior ulnar
Fig.107: Ulnar artery &nerve and median recurrent
nerve in front of forearm (Deep dissection)
Common
Ulnar N. & A. interosseous
Post. Interosseous
Tendons of flexor recurrent
digitorum
superficialis Post. Interosseous

Tendon of Flexor Ant. interosseous

carpi ulnaris
Flexor retinaculum Ulnar artery
Flexor retinaculum 
Fig.108: Ulnar A. & N. in the Fig.109: Branches of the upper
lower part of front of forearm part of ulnar artery (anterior view)

 Forearm 128

- Branches:
 Near its origin, it gives posterior interosseous recurrent
artery, which ascends to anastomose with the posterior
descending branch of profunda on the back of lateral
epicondyle.
 Muscular branches to the muscles of the back of forearm.

 In the forearm: the ulnar artery gives muscular branches to supply

the muscles on the medial (ulnar) side of the forearm.

 At the wrist: The ulnar artery gives:

1. Anterior carpal artery: crosses the front of the carpus deep to
the flexor tendons to anastomose with anterior carpal branch of
radial artery to form anterior carpal arch.
2. Posterior carpal artery: turns backwards then runs laterally
across the back of the carpus deep to the extensor tendons to
anastomose with posterior carpal branch of radial artery to form
posterior carpal arch.

Surface anatomy of ulnar artery: it is represented by a line passing through

three points:
Point 1: midway between the epicondyles of the humerus medial to the tendon
of the biceps.
Point 2: at the medial side of the forearm at the junction of the upper one third
with the lower two thirds.
Point 3: just lateral to the pisiform bone at the wrist.
 Forearm 129

NERVES IN THE FOREARM

Ulnar Nerve
- Course and Relations (Figs. 107, 108, 110):
A. In the forearm:
 it enters the forearm by passing between the two head of flexor
carpi ulnaris muscle, accompanied by posterior ulnar recurrent
artery.
 Then, it descends on the medial part of the front of the forearm
medial to ulnar artery (see ulnar artery), lying on the medial part of
the anterior surface of flexor digitorum profundus throughout its
whole course in the forearm.
 In the upper two thirds of forearm, the ulnar nerve descends under
cover of the flexor carpi ulnaris.
 In the lower third of forearm, it becomes superficial (only covered
by skin, superficial and deep fasciae) between the tendon of flexor
carpi ulnaris (medial to it) and tendons of flexor digitorum
superficialis (lateral to it).

B. At the wrist: it pierces the deep fascia and descends superficial to the
flexor retinaculum, sometimes it is covered by a superficial layer of the
retinaculum, lateral to the pisiform bone.
- End: in front of the flexor retinaculum by dividing into a superficial branch
(mainly cutaneous) and a deep branch (muscular).
- Branches:
1. Articular branches: to supply elbow joint.
2. Muscular branches: to supply flexor carpi ulnaris and the medial
half of flexor digitorum profundus.
3. Cutaneous branches:
 Palmar cutaneous branch: arises from ulnar nerve just below
the middle of the forearm and pierces the deep fascia and
descends superficial to the flexor retinaculum to supply the skin
of the medial third of palm (skin of hypothenar eminence).
 Dorsal cutaneous branch: arises from the ulnar nerve just below
the middle of forearm and turns backwards around the ulnar
border of the forearm under cover of the tendon of flexor carpi
ulnaris to reach the dorsum of the hand where it pierces the
deep fascia and divides into two dorsal digital nerves to supply:
a. Skin of medial third of dorsum of the hand.
b. Skin of the dorsal surface of little finger and medial half of
ring finger (the medial 1 1/2 fingers).
 Forearm 130

Median Nerve
- Course and Relations (Figs. 105, 107, 108, 110):
A. In the forearm:
 It enters the cubital fossa medial to the lower part of the brachial
artery and the upper part of ulnar artery where it is crossed
superficially by the bicipital aponeurosis which separates it from
median cubital vein.
 It leaves the cubital fossa by passing between the two heads of
pronator teres crossing in front of the ulnar artery, but separated
from it by the deep head of the muscle
 Then, it descends through the gap between the two heads of flexor
digitorum superficialis to reach its deep surface where it descends
in the middle of the front of the forearm between the flexor
digitorum superficialis and lateral half of profundus, adhering to the
deep surface of flexor digitorum superficialis.
 Immediately above the wrist it becomes superficial between the
tendon of flexor carpi radialis (lateral to it) and the tendons of
flexor digitorum superficialis (medial to it).
B. At the wrist: median nerve enters the palm by passing deep to the
flexor retinaculum (i.e., passing through the carpal tunnel).

- End: it ends in the carpal tunnel by dividing into two terminal divisions (lateral
and medial).
- Branches:
1. Articular branches (in the cubital fossa): supply the elbow and
superior radio-ulnar joint.
2. Muscular branches (in the cubital fossa): supply four muscles
(pronator teres, flexor carpi radialis, palmaris longus and flexor
digitorum superficialis).
3. Anterior interosseous nerve:
 Arises from median nerve as it emerges between the two heads of
pronator teres.
 It descends on the anterior surface of the interosseous membrane
(accompanied by anterior interosseous artery) where it lies
between flexor pollicis longus (lateral to it) and flexor digitorum
profundus (medial to it).
 Then it disappears deep to pronator quadratus and ends by
supplying inferior radio-ulnar and wrist joints.
 It supplies flexor pollicis longus, pronator quadratus and lateral half
of flexor digitorum profundus (i.e., it supplies all deep flexors of the
 Forearm 131

forearm except medial half of flexor digitorum profundus which is
supplied by ulnar nerve).

4. Palmar cutaneous branch: arises from median nerve one inch above
the wrist, pierces the deep fascia and descends superficial to the flexor
retinaculum outside the carpal tunnel to supply the skin of the lateral
two thirds of the palm of the hand (skin of the hollow of the hand and
the thenar eminence) except the proximal small part of thenar skin
which is supplied by lateral cutaneous nerve of forearm.
 Forearm 132

Superficial Radial Nerve

- Origin: it begins in front of the lateral epicondyle as the continuation of

radial nerve immediately below the origin of posterior interosseous nerve.
- Course (Figs. 105, 111, 112):
 It descends in the lateral part of the front of the forearm overlapped by
brachio-radialis muscle lying on the lateral side of the radial artery as follows:
1. In the upper one third of the forearm, it is separated from the artery by a
triangular gap.
2. In the middle one third of the forearm, it is closely lateral to the artery.
3. In the lower one third of the forearm, it leaves the artery by turning
backwards around lateral surface of radius undercover of the tendon of
brachio-radialis.
 Short distance above the wrist it appears from undercover of brachio-radialis
tendon, pierces the deep fascia and descends to cross the roof of the
anatomical snuff-box, passing superficial to the tendons forming its
boundaries, to reach the dorsum of the hand.
- End and branches: it ends in the dorsum of the hand by dividing into five
dorsal digital nerves as follows:
1. Two for both sides of the thumb.
2. One for the lateral border of the index.
3. Two for the two clefts between the index, middle and ring fingers supplying
their adjacent sides.
These dorsal digital branches supply the skin of lateral two thirds of dorsum of
hand as well as the skin of dorsal aspect of the lateral 3 1/2 fingers as far as
their distal halves only.
N.B.
Digital branches of median nerve turn backwards to supply the skin of the
dorsal aspect of the distal halves of the lateral 3 1/2 fingers.
They also overlap the whole area of skin supplied by the superficial radial
nerve except a triangular area on the dorsum of the web between the thumb
and index fingers (which is supplied only by superficial radial nerve).
 Forearm 133


Fig. 111: Course & branches of posterior interosseous N. and

dorsal digital branches of suprtficial radial N. (Back of forearm)
 Forearm 134

Posterior Interosseous Nerve

- Origin (Fig. 111): arises from the radial nerve in front of the lateral
epicondyle.
- Course: it has the following pathway:
 It descends in front of the elbow under cover of brachio-radialis.
 It first supplies the extensor carpi radialis brevis and supinator, then it
pierces the supinator muscle.
 Within the substance of supinator it winds around the lateral side of the
upper third of the shaft of radius splitting the muscle into superficial and
deep layers.
 It emerges from the muscle in the back of the forearm, where it descends
(with the posterior interosseous artery) between the superficial and deep
extensors of forearm.
 Then it leaves the posterior interosseous artery by passing under cover of
the extensor pollicis longus to join the anterior interosseous artery directly
on the back of the interosseous membrane.
 Finally, it descends, together with the anterior interosseous artery, deep
to the extensor retinaculum through the 4Th compartment to reach back of
the wrist.
- End: it ends in expanded termination (pseudoganglion) giving articular
filaments.
- Branches:
 Articular: terminal branches to supply inferior radio-ulnar joint, wrist joint
and some inter-carpal joints
 Muscular: to all extensor muscles on the back of the forearm (superficial
and deep) except brachio-radialis, extensor carpi radialis longus and
anconeus.
 Forearm 135

Flexor Retinaculum

- Definition: it is a thickened transverse band of deep fascia which crosses in

front of the carpus and converts the anterior concavity of the bony carpal arch
into carpal tunnel (Figs. 110, 113, 114).
- Attachments:
1. Medially: to pisiform and hook of hamate.
2. Laterally: it splits into two laminae:
• A superficial lamina attached to tubercle of scaphoid and crest of
trapezium.
• A deep lamina attached to medial lip of the groove on the trapezium. With
this groove the two laminae form a special tunnel for the tendon of flexor
carpi radialis and its synovial sheath.
3. Below: it is continuous with the deep fascia of the palm of the hand
especially with the apex of the palmar aponeurosis.
4. Above: It is continuous with the deep fascia on the front of the forearm.
- Structures passing superficial to it: from medial to lateral as
follows:
1. Ulnar nerve
2. Ulnar artery
3. Palmar cutaneous branch of ulnar nerve
4. Tendon of palmaris longus
5. Palmar cutaneous branch of median nerve
- Structures passing deep to it:
A. In the carpal tunnel:
1. Tendons of three flexor muscles (nine tendons): Four of flexor
digitorum superficialis; four of flexor digitorum profundus; one of
flexor pollicis longus.
2. Two synovial sheaths: Ulnar and radial bursae.
3. One nerve: Median nerve (lies directly under cover of the
retinaculum).
4. Recurrent branch of the deep palmar arch (the deepest structure in
the tunnel).
B. In special tunnel: tendon of flexor carpi radialis and its synovial
sheath.
 Forearm 136

- Muscles attached to its anterior surface:
 Laterally: Thenar muscles (origin).
 Medially: Hypothenar muscle (origin).
 In the middle: Tendon of palmaris longus (insertion)

* Carpal Tunnel
- Boundaries (Fig. 124):
 The sides and floor consist of the anterior surface of the carpal bones
forming the bony carpal arch.
 Roof: Flexor retinaculum
- Contents:
1. Median nerve: the most superficial structure.
2. Flexor tendons and their synovial sheaths:
 Four tendons of flexor digitorum superficialis (arranged in two rows).
 Four tendons of flexor digitorum profundus (arranged in one deep row).
 The eight tendons are surrounded by the common flexor synovial
sheath (ulnar bursa).
 One tendon of flexor pollicis longus, surrounded by its own synovial
sheath (radial bursa).
3. Reccurent branches of the deep palmar arch to join the carpal arch.

Clinical importance:
Carpal tunnel syndrome: it is a compression of the median nerve while passing
through the carpal tunnel.
This may be caused by Inflammation of synovial sheaths of flexor tendons, arthritic
changes of the intercarpal joints, osteophytes of the carpal bones, dislocation of
lunate bone or accumulation of fluid as blood or pus in the carpal tunnel.
RESULTS:
See median nerve injury p.186
 Forearm 137

Fig. 113: Attachments of flexor
retinaculum & structures passing
deep to it

Median nerve

Radial artery& its

superficial palmer br. Ulnar artery&nerve

Flexor carpi radialis Tendon of flexor

tendon carpi ulnaris

Flexor pollicis longus Pisiform bone

tendon

Tubercle of scaphoid Flexor retinaculum

Trapezium Hook of hamate

Flexor digitorum
superficialis &
profundus tendons


Fig. 114: Carpal tunnel (Cross section)


 Forearm 138

Extensor Retinaculum

- Definition: it is a thickened band of deep fascia of the forearm which

extends obliquely across the back of the wrist.
- Attachment (Figs. 115, 116, 117):
 Laterally: to the sharp anterior border of the lower end of radius.
 Medially: to the triquetral and pisiform bone.
 As it crosses the back of the wrist, it is attached to the ridges on the
back of the lower end of radius by fibrous septa which divide the space
deep to it into six compartments transmitting the extensor tendons and
their synovial sheathes.
- Compartments deep to the retinaculum: from lateral to medial:
1. First compartment (the most lateral):
• It lies on a groove on the lateral side of the lower end of radius.
• It transmits the tendons of abductor pollicis longus and extensor pollicis
brevis.
2. Second compartment:
• It lies on a shallow groove on the back of the lower end of radius lateral
to the dorsal tubercle of Lister.
• It contains the tendons of extensor carpi radialis longus and brevis.
3. Third compartment:
• It lies in a deep groove on back of lower end of radius just medial to the
dorsal tubercle of Lister.
• It contains the tendon of extensor pollicis longus.
4. Fourth compartment:
• It lies on the most medial part of the back of the lower end of radius.
• It contains the four tendons of extensor digitorum, the tendon of extensor
indicis, posterior interosseous nerve and anterior interosseous artery.
 Forearm 139
 Fig. 115: External retinaculum
(back of forearm &hand)

Extensor digitorum
ulnaris
minimi

Intertendinous connections


4
Indicis
longus

minimi brevis

longus

brevis

Fig. 116: Compartments deep

to external retinaculum
(Cross section) 

Fig. 117: Lower end of radius

(Posterior view)

 Forearm 140

5. Fifth compartment:
• It lies on the back of the inferior radio-ulnar joint.
• It contains the tendon of the extensor digiti minimi.
6. Sixth compartment:
• It lies in a groove on the back of the lower end of the ulna between its
head and its styloid process.
• It contains the tendon of extensor carpi ulnaris.
- Relations of the retinaculum:
 Laterally: the retinaculum is crossed by the termination of the
superficial radial nerve and lower part of the cephalic vein.
 Medially: it is crossed by the dorsal cutaneous branch of the ulnar
nerve and beginning of the basilic vein.
 Forearm 141

Formative assessment

I. Mention the branches of the anterior Interosseous artery.

II. Describe the flexor retinaculum and strictures passing deep to it.
III.MCQ: choose the correct answer:
1- Concerning the boundaries of the cubital fossa :
a. The floor is formed by the brachialis and supinator muscles.
b. The roof is formed by the skin, fascia and bicipital aponeurosis.
c. Lateral boundary is formed by the lateral margin of the brachioradialis
muscle.
d. Medial boundary is formed by the medial margin of the pronator teres
muscle.
2- Concerning the contents of the cubital fossa, one is wrong :
a. Median nerve.
b. Termination of the radial artery.
c. Ulnar artery.
d. Radial nerve.
3- Regarding anatomical snuff box, one statement is incorrect:
a. It is bounded medially by the tendon of extensor pollicis longus.
b. It is bounded laterally by the tendons of abductor pollicis longus and
extensor pollicis brevis.
c. The cephalic vein usually crosses its roof.
d. The capitate can be felt in its floor.
4- One of the following branches arises from the ulnar artery:
a. Common Interosseous artery.
b. Radial recurrent artery.
c. Anterior carpal artery.
d. Superficial palmar artery.


 Hand 142

CHAPTER 8

ILOs:
By the end of the lectures, the student should be able to:
 Describe the palmar aponeurosis and identify its function.
 Describe superficial distal pulp space of the finger and interpret its clinical
importance.
 Describe the nerve supply and recognize the action of the thenar muscles,
hypothenar muscles, lumbricals and interossei.
 Practice flexion, extension, adduction and abduction of all digits plus
opposition of the thumb.
 Define the fibrous flexor sheathes and describe its attachment.
 Describe the course and termination and branches of the ulnar artery and
radial artery in the hand.
 Identify the origin, locate the site and describe the formation and branches
of the superficial and deep palmar arches.
 Describe the anterior and posterior carpal arches.
 Explain the deformity caused by injury of the ulnar and median nerves.
 Demonstrate the sites of anastomoses between the ulnar and radial arteries
in the hand.

HAND
SKIN OF THE HAND
The skin of the palm of the hand has the following features:
 It is thick and hairless.
 It is fixed to the underlying deep fascia by numerous fibrous bands.
 It shows many flexure creases at sites of skin movement, which are not
necessary placed at the site of joints.
 It contains large number of sweat glands.

N.B. The skin on dorsum of the hand is thin, hairy and freely mobile.

DEEP FASCIA OF THE PALM

It consists of 3 parts (Fig. 118):

 Lateral part: thin and covers the thenar eminence.
 Medial part: thin and covers the hypothenar eminence.
 Central part: thick and strong and covers the intermediate compartment. It
is called the palmar aponeurosis.
 Hand 143


4 slips of the base

of the aponeurosis Palmer
aponeurosis
(Cut & reflected)

Palmer Deep fascia covering

aponeurosis thenar eminence

Superficial palmer arch

Common synovial sheath of

long flexor tendons
Median nerve

Tendon of Palmaris longus

Flexor retinaculum
 
Fig. 118: Attachments of the palmer Fig. 119: Stuctures deep to palmer
aponeurosis aponeurosis

Thenar muscles

Superficial palmer br. of Palmer cutaneous branch

radial A. & recurrent of median nerve
muscular br. of median N.

Fascia covering
adductor pollicis

Palmer digital
branches of
Median N.

First dorsal
inteross.
muscle

Thenar space (deep

to flexor
st
tendons&1 Midpalmar space (deep to flexor
lumbricla tendons & medial 3 lumbricals) 
Septum separaring
thenar space from
midpalmar space Fig. 120: Palmer surface of hand after removal of palmer
aponeurosis showing limits & contents of the fascial spaces
 Hand 144

Palmar aponeurosis
It forms the central part of the deep fascia of the palm. It is the thickest and
strongest part of it. It is firmly attached to the overlying skin of the palm by
dense fibrous tissue.
- Functions: it protects the tendons, vessels and nerves which go to the
fingers.

- Shape (Figs. 118, 119): it is triangular in shape having:

 An apex: it is directed upwards and fuses with the flexor retinaculum. It
receives the insertion of palmaris longus tendon.
 A base: it divides into four slips; each slip passes to the root of the finger
and becomes continuous with the fibrous flexor sheath of one of the medial
four fingers.
 Lateral margin: it is continuous with the deep fascia covering the thenar
eminence which is much thinner.
 Medial margin: it is continuous with the thin deep fascia covering the
hypothenar eminence. It gives origin to the palmaris brevis muscle

- Fibrous Septa: the palmar aponeurosis sends 3 palmar septa deeply into
the underlying tissues (Figs 120, 121-a,b), as follows:
1. Lateral palmar septum: arises from the lateral border of the
aponeurosis and passes deeply to get attached to the 1st metacarpal bone.
It is pierced by the branches of the median nerve to supply the thenar
muscles.
2. Medial palmar septum: arises from the medial border of the palmar
aponeurosis and passes deeply to get attched to the 5th metacarpal bone.
It is pierced by the deep branches of the ulnar nerve and ulnar artery.
3. Intermediate palmar septum: passes from the deep surface of the
palmar aponeurosis, near its lateral margin, and goes deeply between the
tendons of the index finger and those of the other fingers to get attached
to the palmar surface of the 3rd metacarpal bone.

- Relations: the deep surface is related to the fascial spaces of the palm of
the hand.
 Hand 145

Fascial spaces of the hand
(Intermediate compartment of the palm)

- Boundaries (Figs. 120, 121-a,b):

 Ventrally (roof): is formed by the palmar aponeurosis.
 Dorsally (floor): is formed by the 3rd, 4th and 5th metacarpal bones and
the related interosseous muscles as well as the adductor pollicis muscle.
 Medially: the medial palmar septum.
 Laterally: the lateral palmar septum.

- Subdivision: it is divided into two spaces as follows:

1. Mid-palmar (middle palmar) space:

It is the medial space underneath the palmar aponeurosis (Figs. 120, 121-
a,b)
* Boundaries:
 Laterally: intermediate palmar septum.
 Medially: medial palmar septum.
 Ventrally: palmar aponeurosis.
 Dorsally: 3rd, 4th and 5th metacarpal bones and the related interoseous
muscles.

* Contents:
 long flexor tendons of the digitorum superfiocialis and profundus to
the 3rd, 4th and 5th fingers
 2nd, 3rd and 4th lumbrical muscles attached to the respective tendons
of flexor digitorum profundus.
 Digital nerves and vessels to the medial three and half fingers (little,
ring, middle and medial 1/2 of the index).
* Communications:
 Distally: with the webs between the medial 4 fingers.
 Proximally: with the space deep to the common synovial sheath in the
carpal tunnel.

2. Thenar space: it is the lateral space underneath the palmar

aponeurosis.
* Boundaries (Fig. 121-a,b):
 Laterally: lateral palmar septum.
 Medially: intermediate palmar septum.
 Ventrally: palmar aponeurosis.
 Dorsally: the transverse head of the adductor pollicis and the
covering fascia.
* Contents:
 Long flexor tendons of the index finger and the thumb.
 1st lumbrical muscle (related to the index finger).
 Hand 146

 Digital nerves and vessels to the lateral one and half fingers (thumb
and lateral 1/2 of the index finger).

* Communications:
 Distally: with the web of the thumb (the fold of skin between the
thumb and the index finger)
 Proximally: with the space deep to the common synovial sheath in
the carpal tunnel.

N.B. Space of Parona

It is the space lying between pronator quadratus posteriorly and flexor tendons of the
forearm in front.
It is continuous with the deep palmar space of the palm behind the long flexor tendons
in the carpal tunnel.
Infection may extend from Parona space to the spaces of the palm and vice versa.

Superficial distal pulp space of the finger

 It is the pulp space of the distal phalanx (at the tip of the finger) (Fig.
121-c).
 It is very tightly packed with small lobules of subcutaneous fat
separated by many fibrous septa, which pass from the skin to the
periosteum of the distal phalanx. Only a very little space is left for any
material to collect in it and when it is inflamed, it is very painful
because pus will be entrapped under tension in this narrow space.
N.B:
Blood vessels of the shaft and head, but not of the base, of the terminal
phalanx traverse the pulp space.
Severe infection of the pulp space may result in thrombosis of the vessels
of the shaft and head of the distal phalanx and their consequent death.
The base is spared (not affected).
 Hand 147


(C):

(A)

(B) Intermediate fibrous septum



Fig.121(A): Palmer surface of hand showing divisions of the intermediate compartment

Fig.121(B): Boundaries and contents of the fascial spaces of hand (Coss section)
Fig.121(C): Distal pulp space of the finger (Sagittal section).
 Hand 148

MUSCLES OF THE HAND
I. Lateral muscles of the palm:
A. Muscles of thenar eminence:
 Abductor pollicis brevis
 Flexor pollicis brevis
 Opponens pollicis
B. Adductor pollicis muscle
II. Medial muscles of the palm:
A. Muscles of hypothenar eminence:
 Abductor digiti minimi
 Flexor digiti minimi brevis
 Opponens digiti minimi
B. Palmaris brevis muscle
III. Intermediate muscles of the palm
A. Lumbricals
B. Interossei:
 Four palmar
 Four dorsal

I. Lateral Muscles of the Palm

A. Muscles of the thenar eminence (Figs. 122, 123, 124, 125, 126,
127):
- Origin:
 Abductor pollicis brevis: tubercle of scaphoid, crest of trapezium and
lateral side of flexor retinaculum.
 Flexor pollicis brevis: crest of trapezium and lateral side of flexor
retinaculum.
 Opponens pollicis: crest of trapezium and lateral side of flexor
retinaculum.
- Insertion:
 Abductor pollicis brevis: into the lateral side of the base of proximal
phalanx of the thumb.
 Flexor pollicis brevis: into lateral side of the base of the proximal
phalanx of the thumb.
 Opponens pollicis: into the lateral surface of the shaft of first
metacarpal bone.
- Common Nerve Supply: median nerve (recurrent muscular
branch).

N.B. The flexor pollicis brevis may be supplied, in addition, by deep branch of
ulnar nerve or may be supplied only by deep branch of ulnar nerve.
 Hand 149


Thenar muscles Palmaris brevis

Hypothenar
Adductor pollicis muscles
muscle

Fig. 122: Palmer surface of hand 

Fig. 123: Palmer surface of hand showing thenar, hypothenar & lumbrical muscles
 Hand 150

- Action:
 Abductor pollicis brevis: abducts the carpo-metacarpal joint of the
thumb.
 Flexor pollicis brevis: flexes the carpo-metacarpal and
metacarpophalangeal joints of the thumb.
 Opponens pollicis: opposes the thumb against other fingers, acting
only on the carpo-metacarpal joint. (opposition = flexion + medial
rotation)

B. Adductor pollicis
- Origin: By two heads:
 Oblique head: from the bases of 2nd and 3rd metacarpal bones.
 Transverse head: from the front of the shaft of 3rd metacarpal bone.
- Insertion: into the medial side of the base of proximal phalanx of the
thumb, in common with the flexor pollicis brevis.
- Nerve supply: deep branch of ulnar nerve.
- Action: adducts the thumb at the carpo-metacarpal joint.


Fig. 124: Attachments of abductor pollicis brevis & abductor digiti minimi
(Anterior view)
 Hand 151

Fig. 125: Attachments of flexor
pollicis brevis & flexor digiti minimi

(Anterior view)



Fig. 126: Attachments of opponens pollicis &oponens digiti minimi (Anterior view)

Fig. 127: Attachments of adductors pollicis (Anterior view)


 Hand 152

II. Medial Muscles of the Palm
A. Muscles of the hypothenar eminence(Figs. 123, 124, 125,
126)
- Origin:
 Abductor digiti minimi: pisiform, hook of hamate and medial side of
flexor retinaculum.
 Flexor digiti minimi brevis: hook of hamate and medial side of flexor
retinaculum.
 Opponens digiti minimi: hook of hamate and medial side of flexor
retinaculum.
- Insertion:

Abductor digiti minimi: into the medial side of the base of the
proximal phalanx of little finger.
 Flexor digiti minimi brevis: into the medial side of the base of the
proximal phalanx of little finger.
 Opponens digiti minimi: into the medial surface of the shaft of the
5th metacarpal bone.
- Common nerve supply: deep branch of ulnar nerve.
- Action:
 Abductor digiti minimi: abducts metacarpo-phalangeal joint of the
little finger.
 Flexor digiti minimi brevis: flexes metacarpo-phalangeal joint of the
little finger.
 Opponens digiti minimi: opposes little finger against the thumb.
B. Palmaris brevis muscle
It lies in the superficial fascia of the palm beneath the skin of the
hypothenar eminence (Fig. 122).
- Origin: from flexor retinaculum and medial border of palmar
aponeurosis.
- Insertion: into the skin of the medial side of the palm.
- Nerve supply: superficial branch of ulnar nerve.
- Action: deepens the hollow of the palm to provide a firm grip by
wrinkling and raising the skin on the medial side of the palm.
III. Intermediate Muscles of the Palm

A. Lumbricals: they are four muscles (Fig. 128).

- Origin: they arise from the four tendons of flexor digitorum profundus
in the palm.
 Lateral two lumbricals: each arises by a single head from the lateral
margin of the lateral two tendons of flexor digitorum profundus.
 Medial two lumbricals: each arises by two heads from the adjacent
margins of the medial three tendons of flexor digitorum profundus.
 Hand 153


(Anterior view)

Tendons of flexor
digitorum profunmdus Fig. 128: Attachments of
the lumbricals


Fig. 129: Attachments of

palmar interossei


Fig. 130: Attachments

of dorsal interossei 
 Hand 154

- Insertion: tendons of lumbricals turn backwards on the lateral side of
the metacarpo-phalangeal joints of the medial four fingers to join the
corresponding extensor expansions and finally become inserted into
the dorsal aspects of the bases of distal phalanges of medial four
fingers.
- Nerve Supply:
 Lateral two lumbricals: median nerve
 Medial two lumbricals: deep branch of ulnar nerve
- Action: acting with the interossei, they flex the metacarpo-phalangeal
joints and extend the interphalangeal joints of medial four fingers, i.e.,
they are responsible for putting the fingers in the writing position.
B. Interosseous muscles:
1. Palmar interossei: four muscles, the first one may be absent (Fig.
129).
- Origin: each arises by a single head from the palmar surfaces of the
first, second, fourth and fifth metacarpal bones (of thumb, index, ring
and little fingers).
- Insertion:
 The 1st palmar interosseous muscle: is inserted into the medial
side of the base of the proximal phalynx of the thumb.
 The 2nd, 3rd and 4th interossei: their tendons turn backwards to
join the extensor expansion of the corresponding finger (index, ring
and little fingers) as follows:
a. The 2nd palmar interosseous crosses medial to metacarpo-
phalangeal joint of the index finger to reach the extensor
expansion.
b. The third and the fourth palmar interossei cross lateral to the
metacarop-phalangeal joints of the ring and little fingers to reach
the corresponding extensor expansion.
- Nerve supply: all are supplied by the deep branch of ulnar nerve
- Action:
 Adduct the thumb, index, ring and little fingers towards the middle
finger.
 Acting with the lumbricals and dorsal interossei, they flex the
metacarpo-phalangeal joints and extend the interphalangeal joints of
medial four fingers i.e. putt the fingers in the writing position.
N.B. The middle line of the fingers is the middle line of the middle finger.
2. Dorsal interossei: four muscles (Fig.130).
- Origin: each arises by two heads from the adjacent sides of the two
metacarpal bones between which it lies i.e. the 1st dorsal
interosseous (the largestof all interossei) arises from adjacent sides of
the 1st and 2nd metacarpal bone, the 2nd dorsal arises from adjacent
sides of the 2nd and 3rd metacarpal bone, , the 3rd dorsal arises from
 Hand 155

adjacent sides of the 3rd and 4th metacarpal bone and the 4th dorsal
arises from adjacent sides of the 4th and 5th metacarpal bone.
- Insertion: their tendons join the extensor expansions of the index,
middle and ring fingers, in the following way:
 First and second dorsal interossei cross lateral to the metacarpo-
phalangeal joints of the index and middle fingers to reach their
extensor expansions.
 Third and fourth dorsal interossei cross medial to the metacarpo-
phalangeal joints of the middle and ring fingers to reach their
extensor expansions. i.e. The middle finger receives two dorsal
interossei, the 2nd and 3rd.
- Nerve supply: all are supplied by the deep branch of ulnar nerve.
- Action:
 Dorsal interossei abduct the index, middle and ring fingers from the
line of the middle finger. i.e., the middle finger has double abductors.
 Acting with the lumbricals and palmar interossei, they put the hand in
writing position.
N.B. The thumb and the little finger have no dorsal interossei as they have their
own abductors
FIBROUS FLEXOR SHEATHES
- Definition: a fibrous flexor sheath is the deep fascia on the anterior
surface of a finger which is thickened to be able to hold the flexor tendons
in contact with the anterior surfaces of the phalanges and the
interphalangeal joints during flexion of the fingers (Fig. 131).
- Attachment:
 The edges are attached to the margins of its phalanges and margins of
the metacarpo-phalangeal and inter-phalangeal joints.
 Its proximal end is continuous with a slip of palmar aponeurosis.
 Its distal end is attached to the anterior surface of the terminal phalanx
immediately beyond the insertion of the flexor digitorum profundus
tendon.
 The fibrous flexor sheath form, with the phalanges, a canal (digital
canal) in which the flexor tendons and their synovial sheaths lie. In the
thumb, this canal contains the tendon of flexor pollicis longus and its
synovial sheath.
 At each crease of the finger the skin is attached to the fibrous flexor
sheath, therefore, the pulp over each phalanx is a separate space
isolated from its neighbors. Infection can spread from one pulp to the
other along the neuro-vascular digital bundle.
N.B. Deep fascia, flexor fibrous sheath, does not extend into the distal pulp
space.
 Hand 156

SYNOVIAL SHEATHES
A. Common Flexor Sheath (Ulnar bursa) (Fig.132):
 As the eight tendons of flexor digitorum superficialis and profundus pass
through the carpal tunnel deep to the flexor retinaculum they are
enclosed in a common synovial sheath (ulnar bursa) with the tendons of
the flexor digitorum superficialis lying superficial to those of the
profundus.
 The common flexor sheath has a parietal layer lining the tunnel and a
visceral layer applied to the tendons. The tendons invaginate the sheath
from the lateral side.
 The sheath extends proximally for one inch in the forearm above the
flexor retinaculum. Distally it ends blindly opposite the middle of the
meta-carpal bones (the proximal crease of palm) except its medial side,
which becomes continuous with the synovial sheath of the little finger.
B. Flexor Pollicis Sheath (Radial bursa) (Fig.132):
 The tendon of flexor pollicis longus has its own synovial sheath, in the
carpal tunnel.
 It extends proximally for one inch in the forearm while distally it extends
down to the insertion of the muscle.
N.B. The radial and ulnar bursae usually communicate with each other in the
carpal tunnel.
C. Digital Synovial Sheaths (Digital bursae) (Fig.132):
 They enclose the flexor tendons of each of the medial for fingers in the
digital canals. Each sheath has two layers; one covers the tendon while
the other lines the canal made by the fibrous flexor sheath and the
phalanges.
 Proximally they extend only to the level of the distal crease of the palm
(opposite the heads of the metacarpal bones) except for the synovial
sheath of the little finger, which is continuous proximally with ulnar
bursa. Distally, the digital synovial sheathes extend down to the
insertion of the tendons.
N.B.
*The flexor Carpi Radialis Tendon has its own synovial sheath in its own compartment in
the groove of trapezium.
The two layers of the synovial sheath are separated by a very narrow space, filled with
minimal amount of synovial fluid.
*The synovial sheathes of the index, middle and ring fingers do not communicate with
the ulnar bursa but they are separated from it by a distance of 1- 3 cm where the
tendons are bare (not covered by synovial sheaths).
*Infection of the 2nd, 3rd and 4th synovial sheaths remain localized to their fingers.
Infection of the thumb or little finger (ulnar and radial bursae) may spread to the palm
of the hand , carpal tunnel and forearm.
 Hand 157

 Hand 158

ARTERIES OF THE HAND
They are the terminations of the ulnar and radial arteries in the hand, which end
by forming superficial and deep palmar arches, respectively.

Ulnar artery in the hand

- Course and relations (Fig. 133):
The ulnar artery enters the palm by crossing superfiacial to the medial part of
the flxor retinaculum (sometimes passing through its substances between its
superficial and deep parts). Here the artery has the following relations:
1. It lies just lateral to the ulnar nerve and pisiform bone.
2. It is covered by the Palmaris brevis muscle.
- End: the artery ends by dividing on the front of the flexor retinaculum into
superficial and deep divisions as follows:
a. Deep division (deep palmar branch):
- It passes bachwards between the abductor digiti minimi and flexor
digiti minimi brevis.
- It then penetrates the opponens digiti minimi to anastomose with
the end of the deep palmer arch at the base of the 5 th metacarbal
bone.
- It is accompanied by the deep branch of the ulnar nerve.
b. Superficial division : it runs distally just medial to the hook of hamate
and then curves laterally across the palm to form the superficial
palmar arch.
- Branches of the ulnar artery in the hand: all the branches of the
ulnar artery in the palm arise from the superficial palmar arch.

Superficial palmar arch

- Site: it lies immediately deep to the palmar aponeurosis but superficial to

the flexor tendons and digital branches of the median nerve (Fig. 133).
- Level: it crosses the palm of the hand lying at the level of midshaft of the
metacarpal bones, 1 cm distal to the deep palmer arch.
- Formation: it is formed mainly by the ulnar artery and is completed by the
superficial palmar branch of radial artery at the thenar eminence.

- Branches: it gives four palmar digital arteries:

1. Palmar digital artery to the medial side of the little finger: it arises from
the medial end of the palmer arch under cover of the Palmaris berivis
 Hand 159

2. Three common palmar digital arteries arise from the convexity of the
arch and run to the three clefts between the medial four fingers where
each one is joined by the corresponding palmar metacarpal artery (from
the deep arch) and then divides into a pair of proper palmar digital
arteries to supply the palmar surfaces the adjacent sides of the medial
four fingers.
- Surface Anatomy of the superficial palmar arch:
It corresponds to a curved line, with its convexity directed distally, drawn across the
hand from the distal border of the root of the extended thumb.

Radial artery in the hand

- Course and relations (Figs. 102, 130, 134):
 The artery leaves the forearm by winding backwards round the lateral
side of the wrist crossing superficial to the lateral ligament of the wrist.

 It then crosses the anatomical snuffbox by passing deep to its lateral

boundary formed by the tendons of abductor pollicis longus and
extensor pollicis brevis.
 It then crosses the floor of the box , where it passes over the tendons of
insertion of extensor carpi radialis longus and brevis. Its pulsations can
be felt in the floor of the snuff-box.
 It leaves the anatomical snuff-box by passing deep to its medial
boundary formed by the tendon of extensor pollicis longus to reach the
dorsum of the hand.
 On the dorsum of the hand, it descends towards the proximal part of
the 1st interosseous space (between 1st and 2nd metacarpal bones)
where it passes forwards between the two heads of the 1st dorsal
interosseous muscle to reach the palm of the hand.
 In the palm of the hand, it emerges between the oblique and transverse
heads of adductor pollicis muscle and runs medially immediately distal
to the bases of the metacarpal bones as deep palmar arch.
- End: it ends in the palm of the hand as the deep plamar arch

- Branches (Figs. 133, 135, 136):

* Branches on the dorsum of the hand:
1. Posterior carpal artery: arises from radial artery after turning
backwards reaching the dorsum of the hand. It runs medially across the
back of the carpus deep to the extensor tendons to anastomose with
posterior carpal branch of ulnar artery together forming the posterior
carpal arch.
2. First dorsal digital branch: to the lateral border of the thumb.
3. First dorsal metacarpal artery: arises on the dorsum of the hand just
before the radial artery passes between the two heads of 1 st dorsal
interosseous muscle. It divides into two dorsal digital branches to supply
the adjacent sides of the thumb and index fingers.
 Hand 160

* Branches in the palm of the hand:
1. Princeps pollicis artery: it arises immediately as the radial artery
emerges between the 2 heads of the 1st dorsal interosseous muscle. It
runs distally along the palmar aspect of the 1st metacarpal bone to the
base of the proximal phalanx of the thumb where it divides into two
branches to supply the two sides of its palmar aspect (forming the two
palmar digital branches of the thumb).
2. Radialis indicis artery: it has a variable origin as it may asrise from
the radial artery itself or arise in common with the princes pollicis. It
runs along the lateral side of the index on the palmar aspect (forming
its lateral palmar digital branch).
3. Deep palmar arch: (see Below).

Deep Palmar Arch

- Site: it lies deep to the flexor tendons in the palm of the hand (Fig. 134).
- Level: it crosses the palm of the hand immediately distal to the bases of the
metacarpal bones (1/2 an inch proximal to the superficial palmar arch).
- Formation: it is formed mainly by radial artery and is completed by deep
palmar branch of ulnar artery (they anastomose together at the base of the
5th metacarpal bone).
- Relations: the arch is concave towards the wrist with the deep branch of
ulnar nerve runs in this concavity.
- Branches (Figs. 135, 136):
1. Three palmar metacarpal arteries: they pass to the clefts between the
medial four fingers where they join the corresponding common digital
branches from the superficial palmar arch.
2. Three perforating branches: they pass dorsally from the arch through
the proximal parts of the 2nd, 3rd and 4th intermetacarpal spaces. They
emerge between the heads of origin of the dorsal interosseous muscles
to join the dorsal metacarpal arteries.
3. Recurrent branches: they arise from the concavity of the arch and
ascend in front of the wrist joint to end in the anterior carpal arch.

Surface Anatomy:
the deep palmar arch is represented by a curved line 4 cm long drawn on the palm
from a point just distal to the hook of hamat at the level of the proximal border of
fully extended thumb.
 Hand 161


Radial artery

Superficial palmer branch

of radial a.
Ulnar artery
Abductor pollicis brevis
Deep palmer branch of ulnar
Flexor pollicis brevis artery

Superficial palmer arch

Princeps
pollicis Palmer digital a. of medial
side of little finger

3 Common palmar digital

arteries

Palmar metacarpal branches Proper palmer digital arteries

(From deep palmar arch)

Radialis indicis
(Branch of radial a.)

Fig. 133: Superficial palmer

(Palmer surface of hand) arch
Formation & branches


Radial artery in
the palm of hand

Deep palmar branch of ulnar a.

Deep branch of ulnar N.

Fig.134: Deep palmer arch

(Palmer surface of hand) (Formation & course)
 
 Hand 162


Arterial arches in the hand

There are four arterial arches in the hand (Figs.133, 134, 135, 136) as follows:
1. Anterior Carpal Arch:
 It lies on the front of the carpus deep to the flexor tendons.
 It is formed by the anastomosis of the following arteries which All
together form a cruciate anastomosis:
1. Anterior carpal branch of ulnar artery.
2. Anterior carbal branch of radial artery.
3. A descending branch from anterior interosseous artery.
4. Recurrent branches from deep palmar arch.

2. Posterior Carpal Arch

 It lies on the back of the carpus deep to the extensor tendons.
 It is formed by the following arteries:
1. The posterior carpal branch of ulnar artery.
2. The posterior carpal branch of radial artery.
3. The anterior interosseous artery.
4. The posterior interosseous artry
 The arch gives three dorsal metacarpal arteries (2nd, 3rd and 4th); each
bifurcates
into two dorsal digital branches to supply the adjacent sides of the
medial four fingers. It gives dorsal digital branch to medial border of
little finger.

N.B. The 1st dorsal metacarpal artery arises from radial artery in the dorsum of
the hand.

3. Superficial palmar arch: (see above)

4. Deep palmer arch: (see above)
 Hand 163


Radial artery
Ulnar artery


Superficial palmar br.
of radial a. Recurrent branch of deep palmar arch
Hook of hamate
Princeps pollicis





Radialis 
indicis


 
Fig. 135: Palmar aspect of hand showing branches of radial artery, Superficial &
deep palmar arches and anterior carpal arch

Dorsal carpal
branch of ulnar a.
Dorsal carpal branch of radial a.
Dorsal carpal arch
First dorsal digital a.

First dorsal metacarpal a.

 

 
Fig. 136: Dorsal aspect of hand
showing: branches of radial
artery on the dorsum of hand and
 arch
the dorsal carpal
 Hand 164

NERVES IN THE HAND

They are the two terminal branches of ulnar nerve, superficial and deep
branches, and the two terminal branches of median nerve, Lateral and medial
branches.

1. ULNAR NERVE
- Course and relations (Figs. 137, 138): it enters the palm in front of the
medial part of the flexor retinaculum where it gives superficial and deep
terminal branches. Here, the nerve has the following relations:
 It lies lateral to the pisiform bone, just medial to the ulnar artery.
 It is covered (sometimes) by the superficial layer of the flexor retinaculum
and by the paslmaris brevis muscle.

- Branches (Figs. 137, 138):

1. Superficial branch:
 Arises in front of the flexor retinaculum.
 It descends deep to the palmaris brevis muscle, supplying it and then
divides into two palmar digital branches to supply the skin on the
palmar surfaces of little finger and medial half of the ring finger (the
medial 11/2 fingers).
2. Deep branch:
 Arises in front of the flexor retinaculum.
 Then it dips between abductor and flexor digiti minimi in company with
the deep branch of the ulnar artery.
 It then pierces the opponens digiti minimi, curves round the hook of the
hamate and turns laterally across the palm, lying in the concavity of the
deep palmar arch (deep to the flexor tendons).
 It ends near the lateral border of the palm by breaking up into terminal
branches.
 It gives the following branches:
* Muscular branches to the following muscles:
- Muscles of the hypothenar eminence.
- the medial two lumbricals
- All the 8 interosseous muscles
- adductor pollicis
- additional supply to the flexor pollicis brevis (sometimes).
* Articular branches: to the wrist and the metacarpo-phalangeal
joints.
 Hand 165

(Palmar surface of hand)

nd
2 lumbrical
3 digiti minimi:

- Abductor st
1 lumbrical

- Flexor Brs of lateral division of

median nerve
- opponens
Flexor pollicis brevis
Brs of ulnar N. :
- Communicating Recurrent muscular brs.
of median N.
- Superficial Opponens pollicis

- Deep

Ulnar N & A
Flexor retinaculum Abductor pollicis brevis


Fig.137: Branches of superficial division of ulnar n. and branches of median n. in hand

Anterior carpal arch Ulnar n.&a.

Medial division of median nerve

Lateral division of median nerve

Recurrent muscular br. of median n.

Deep br.of ulnar
nerve & artery
Superficial br of
ulnar n.

Hook of hamate

Superficial
palmer arch

Deep palmar arch accompanied with the

deep br. of ulnar n.

Fig. 138: Palmar surface of the hand showing the deep branch of ulnar n. lying
in the concavity of deep palmar arch
 Hand 166

2. MEDIAN NERVE
It enters the palm deep to the flexor retinaculum (in the carpal tunnel) where it
divides into two terminal divisions (Figs. 137, 138):

1. Lateral division (the smaller):

 It gives off an important branch (recurrent branch) to supply
the muscles of thenar eminence (flexor pollicis brevis,
abductor pollicis brevis and opponens pollicis).
 It then divides into three palmar digital branches:
i. Two of them supply the palmar surface of both sides of the
thumb.
ii. The third supplies the palmar surface of the lateral side of
the index and gives a muscular branch to the 1st
lumbrical muscle.
2. Medial division: divides into two branches:
 The first passes to the cleft between index and middle
fingers. It gives a muscular branch to the 2nd lumbrical and
then divides into two palmar digital branches to supply the
palmar surfaces of the adjacent sides of the index and
middle fingers.
 The second passes to the cleft between middle and ring
fingers and divides into two palmar digital branches to
supply the palmar surfaces of the adjacent sides of these
two fingers.

N.B.:
*Palmar digital branches of median nerve supply not only the whole
palmar aspect but also turn backwards to supply the distal half of the
dorsal aspects of the lateral 3 1/2 fingers.
*Median nerve is accompanied and supplied by median artery which
is a branch of anterior interosseous artery.
*The deep branch of the ulnar nerve supplies all intrinsic muscles of
the hand except five muscles (lateral two lumbricals and the three
thenar muscles), which are supplied by the median nerve.
 Hand 167

Formative assessment

I. Describe the midpalmar space

II. Mention the branches of deep palmar arch.
III.MCQ
 The Interosseous muscles of the hand are supplied by:
a. Deep branch of ulnar nerve
b. Superficial branch of ulnar nerve
c. Median nerve
d. Posterior Interosseous nerve

 Venous and lymphatic drainage of upper limb 168

CHAPTER 9

.
ILO’s
By the end of the lectures, the student should be able to:
1- Determine the site of the veins of upper limb
2- Locate the surface anatomy of the superficial veins of the upper
limb.
3- Describe the important veins in the upper limb.
4- Determine sites of intravenous injection commonly used.
5- Interpret some clinical problems of faulty intravenous injection
6- Recognize lymph vessels of the upper limb.
7- Describe the lymph nodes of the upper limb
8- Locate the site the different groups of lymph nodes.
9- Determine area drained by each group of lymph nodes.
10-Explain the clinical problems related to the factors maintaining the
venous and lymphatic drainage of the upper limb.

VEINS OF THE UPPER LIMB

The veins of the upper limb are divided into superficial and deep groups, which
communicate freely together and are provided by valves.

I. Superficial Veins: they run in the superficial fascia and they are
larger and more important than the deep veins where they end finally
into them. They begin in the dorsum of the hand and consist of the
following:

a. A superficial dorsal venous network or arch (Fig. 139):

 It lies over the heads of the metacarpal bones.
 It receives veins from the fingers, dorsum of the hand and from
the palm of the hand by veins that perforate the interosseous
spaces.
 It drains in two directions: laterally into the cephalic vein and
medially into the basilic vein.
b. Cephalic Vein (Figs. 139,140, 141):
 It begins from the lateral end of the dorsal venous arch in the
superficial fascia of the roof of the anatomical snuff-box, just
behind the styloid process of radius.
 It runs upwards winding forwards above the wrist to reach the
anterior surface of the forearm, where it ascends in the lateral side
of the front of the forearm.
 Then, it crosses the lateral part of the roof of cubital fossa to reach
the arm.
 Venous and lymphatic drainage of upper limb 169


(Posterior view) 

Fig. 139: Superficial dorsal venous Fig. 140: Superficial veins of forearm
network (Anterior view)
 Venous and lymphatic drainage of upper limb 170

In the arm, it runs in a groove along the lateral border of biceps
muscle.
 Finally, it reaches the delto-pectoral groove where it is
accompanied by the deltoid branch of thoraco-acromial artery and
few deltopectoral lymph nodes. Just below the clavicle, it pierces
the deep fascia and clavi-pectoral fascia to end in the terminal part
of the axillary vein.
c. Basilic Vein (Figs. 139,140, 141):
 It begins from the medial end of the dorsal venous arch.
 It ascends along the postero-medial surface of forearm, then turns
to reach the anterior surface just below the elbow.
 It then crosses the medial part of the roof of cubital fossa to reach
the arm.
 It pierces the deep fascia at the middle of the arm (at the insertion
of the coracobrachialis) to become deep and ascends medial to the
brachial artery.
 At the lower border of the teres major muscle, it is joined by the
two venae comitantes of the brachial artery, together forming
axillary vein.
d. Median vein of the forearm (Figs. 140, 141):
 It begins near the wrist by union of few veins from the palm of
hand. It then ascends in the middle of the front of the forearm.
 below the elbow, it ends in the basilic or the cephalic vein, or it
divides into two veins as follows:
- Median basilic vein: joins the basilic vein
- Median cephalic vein: joins the cephalic vein
a. Median Cubital vein (Fig. 141): it connects cephalic and basilic
veins in the superficial fascia of the roof of the cubital fossa, where it
crosses superficial to the bicipital aponeurosis, which separates it
from brachial artery and median nerve (deep to the aponeurosis).

II. Deep Veins:

a. Venae comitantes (Fig. 142): they accompany the main
arteries. Two veins usually accompany each main artery and these
two veins anastomose with each other. Venae comitantes of radial
and ulnar arteries join the venae comitantes of the brachial artery.
b. Axillary vein: (see page 74).
 Venous and lymphatic drainage of upper limb 171


Fig. 141: Superficial venous drainage

of the upper limb (Anterior view)

Fig. 142: venae comitantes

(Anterior view) of the arteries of the upper
limb (Deep veins) 
 Venous and lymphatic drainage of upper limb 172


Formative assessment

MCQ: choose the correct answer:

1. Median vein of the forearm:
a. Starts by union of small veins of the back of the hand.
b. Continues with the lateral end of the dorsal venous arch.
c. Gives the median basilic and median cephalic veins.
d. It is a common site for intravenous injection.

2. The median cubital vein:

a. Connects the axillary and cephalic veins
b. It is separated from the ulnar artery by the bicipital aponeurosis
c. It is a common vein for intravenous injection
d. It is one of the deep veins in the upper limb
3. The cephalic vein ends in :
a. the axillary vein
b. median cubital vein
c. the subclavian vein
d. the basilica vein
 Venous and lymphatic drainage of upper limb 173

LYMPH DRAINAGE OF THE UPPER LIMB
I. Lymph nodes of the upper limb: they are divided into Superficial
and deep nodes.
A. Deep lymph nodes:
1. Five groups of axillary lymph nodes: (See p.75)
2. Few deep nodes are situated in the cubital fossa, at the bifurcation of the
brachial artery, in the arm along the brachial artery and in the forearm
along the radial and ulnar arteries.
B. Superficial lymph nodes (Figs. 143, 144): they are few scattered nodes
and consist of two groups as follows:
1. Supra-trochlear lymph nodes:
 They lie on the superficial fascia of the roof of the cubital fossa above
the medial epicondyle and medial to the basilic vein.
 They receive few lymph vessels from the medial side of the forearm
and send efferents accompanied the basilic vein to end in the lateral
group of axillary lymph nodes (deep group).
2. Infra-clavicular lymph nodes (deltopectoral):
 They lie beside the cephalic vein in the delto-pectoral groove
immediately below the clavicle.
 Their efferents pierce the clavi-pectoral fascia to reach the apical
group of axillary lymph nodes (deep group), some of these vessels
cross superficial to the clavicle to end in the lower deep cervical
lymph nodes.

II. Lymph vessels of the upper limb: they consist of superficial and
deep groups.
A. Lymph drainage of superficial tissues of the upper limb (Fig. 144):
1. Vessels on the medial side of the wrist:
 Follow the basilic vein in the forearm.
 Just above the elbow some of them end in the supra-trochlear lymph
nodes; their efferents together with the other vessels which have not
ended in the supra-trochlear nodes pierce the deep fascia with the
basilic vein and end in the lateral (humeral) group of axillary lymph
nodes.
2. Vessels on the lateral side of the wrist:
 Follow the cephalic vein in the forearm.
 At the insertion of deltoid, most of them incline medially to pierce the
deep fascia and end in the lateral (humeral) group of axillary lymph
nodes.
 A few continue with the cephalic vein and end in the infra-clavicular
lymph nodes; their efferents pierce the clavi-pectoral fascia to end
into the apical group of axillary lymph nodes.

B. Lymph drainage of the deep tissues of the upper limb

(Figs. 143, 144): follows the main vessels (radial, ulnar,
 Venous and lymphatic drainage of upper limb 174

interosseous and brachial vessels) and end in the lateral
(humeral) group of the axillary lymph nodes.

N.B. Deep lymph vessels from scapular region end in the subscapular group of
axillary lymph nodes and those from pectoral region end in the pectoral group of
the axillary nodes.
 Venous and lymphatic drainage of upper limb 175


Formative assessment

1. Mention the superficial lymph nodes of the upper limb.

2. Explain the edema in the upper limb after radical
mastectomy operation (in cancer breast).


 Cutaneous nerve supply & nerve injuries 176

CHAPTER 10

ILOs
By the end of the lectures, the student should be able to:
1- Recognize the sensory nerves of the upper limb.
2- Determine area of distribution of each nerve.
3- Describe the segments of spinal cord responsible for each skin segments,
4- Locate the site of each segment on the body surface of the upper limb.
5- Interpret some clinical problems resulted from spinal nerve injury
according to the way distribution of each nerve.
6-Describe the effect of injury of brachial plexus.
7-Recognize the motor, sensory effects of each nerve injury in the
upper limb.
8-Determine the deformity of each nerve.
9-Interpret some clinical problems resulted from nerve injury.

CUTANEOUS NERVE SUPPLY OF THE UPPER LIMB

(Figs. 145, 146, 147, 148, 149, 150)
I. Cutaneous nerves of the shoulder region, axilla and
upper arm (Figs.145, 146):
A. One nerve on the back:
 Posterior cutaneous nerve of arm (from radial nerve in the
axilla): it supplies the skin of back of the arm from the deltoid
tuberosity down to the elbow.
B. Two nerves on the medial side:
 Intercosto-brachial nerve: it is the lateral cutaneous branch of
the 2nd intercostals nerve. It emerges from the 2nd intercostals
space and crosses the floor of the axilla supplying it. Then it runs
downwards to supply the skin over the upper half of the medial
side of the arm.
 Medial cutaneous nerve of arm (from medial cord of brachial
plexus): it supplies skin over the lower half of the medial side of
the arm.
C. Three nerves on the lateral side:
 Lateral supra-clavicular nerve (C3, 4): supplies the skin over
the upper half of the deltoid.
 Upper lateral cutaneous nerve of arm (continuation of
posterior branch of axillary nerve): supplies the skin over the
lower half of deltoid.
 Lower lateral cutaneous nerve of arm (from radial nerve in the
spiral groove): supplies the skin from the deltoid tuberosity down
to the elbow.
 Cutaneous nerve supply & nerve injuries 177


Supraclavicular nerves
(from cervical plexus)
1. Palmar cutaneous branch of median nerve: supplies
the lateral two thirds of the palm of hand, except the
Upper lateral cutaneous nervepart of the ball of the thumb which is
proximal
of arm (from axillary n.)
supplied by the termination of the anterior branch of
lateral cutaneous nerve of forearm (originally from
the musculo-cutaneous nerve). Intercostobrachial n.

Lower lateralnerves
B. Cutaneous cutaneousofnerve
the palmar aspect of the fingers: by seven
of arm (from radial n.) Medial cutaneous n. of arm
palmar digital branches which come from:
1. Superficial branch of ulnar nerve: supplies medial 1-1/2 fingers.
2. Lateral and medial divisions of median nerve: supply the lateral 3-
1/2 fingers and turn backwards, over the tips of cutaneous
Medial the fingers,
nervetoof
supply the skin over the distal halves of their dorsal aspects. forearm
C. Cutaneous nerves of the dorsum of the hand:
Lateral cutaneous nerve of forearm
(terminal part of
1. Dorsal musculocutaneous
cutaneous branch ofn.ulnar nerve: supplies the medial third of
the dorsum of hand.
2. Terminal digital branches of superficial radial nerve: Fig. 145: supplies the
Cutaneous
lateral two thirds of the dorsum of hand. innervation of shoulder, arm
D. Cutaneous nerves of the dorsal aspect of the fingers:(Anterior
& forearm by sevenview)
dorsal digital branches which come from:
1. Dorsal
Upper lateralcutaneous
cutaneous branch
nerve of ulnar nerve: supplies the medial 1-1/2
offingers.
arm (from axillary n.) Supraclavicular nerves
 2. Terminal digital branches of the superficial radial (fromnerve: supplies
cervical the
plexus)

dorsal aspect of the lateral 3-1/2 fingers as far as their distal halves
Intercostobrachial n.
(The distal halves are supplied by the palmar digital branches of
the median nerve).
Medial cutaneous n. of arm Posterior cutaneous nerve
of arm (from radial N.)
N.B. Branches of median nerve overlap the whole area of skin
supplied by the superficial radial nerve except a triangular area on the
dorsum of the web between the thumb and index fingers which is
supplied
Posterior only bynerve
cutaneous the superficial
of radial nerve.
forearm
2. (from radial N.)
Lower lateral cutaneous
 nerve of arm (from radial)

Medial cutaneous nerve of

forearm Lateral cutaneous nerve of
forearm (termination of
musculocutaneos N.)

Fig. 146: Cutaneous innervation of

shoulder, arm & forearm
(Posterior view)

 Cutaneous nerve supply & nerve injuries 178

II. Cutaneous nerves of the forearm (Fig.145, 146):
 Lateral cutaneous nerve of forearm: it is the continuation of
musculo-cutaneous nerve. It divides above the elbow into anterior
and posterior branches which supply the skin over the lateral
aspect of the forearm (both in front and behind).
 Medial cutaneous nerve of forearm (from the medial cord of
the brachial plexus): it divides above the elbow into anterior and
posterior branches, which supply the skin over the medial aspect
of the forearm (both in front and behind).
 Posterior cutaneous nerve of forearm (from radial nerve in
the spiral groove): it descends behind the lateral epicondyle to
supply the skin in the middle of the back of the forearm.

III. Cutaneous nerves of the hand (Figs. 147, 148):

A. Cutaneous nerves of the palm of hand:
 Palmar cutaneous branch of ulnar nerve: supplies the medial third
of the palm of the hand.
 Palmar cutaneous branch of median nerve: supplies the lateral two
thirdsof the palm of hand, except the proximal part of the ball of
the thumb, which is supplied by the termination of the anterior
branch of lateral cutaneous nerve of forearm (originally from the
musculo-cutaneous nerve).

B. Cutaneous nerves of the palmar aspect of the fingers: by seven

palmar digital branches, which come from:
 Superficial branch of ulnar nerve: supplies the medial 1-1/2 fingers.
 Lateral and medial divisions of median nerve: supply the lateral 3-
1/2 fingers and turn backwards to supply the skin over the distal
halves of their dorsal aspects.
C. Cutaneous nerves of the dorsum of the hand:
 Dorsal cutaneous branch of ulnar nerve: supplies the medial third
of the palm of hand.
 Superficial radial nerve: supplies the lateral two thirds of the palm
of hand.
D. Cutaneous nerves of the dorsal aspect of the fingers: by seven
dorsal digital branches which come from:
 Dorsal cutaneous branch of ulnar nerve: supplies the medial 1-1/2
fingers.
 Superficial radial nerve: it supplies the dorsal aspect of the lateral
3-1/2 fingers as far as their distal halves (The distal halves are
supplied by the palmar digital branches of the median nerve).

N.B. Branches of median nerve overlap the whole area of skin

supplied by the superficial radial nerve except a triangular area on the
dorsum of the web between the thumb and index fingers, which is
supplied only by the superficial radial nerve.
 Cutaneous nerve supply & nerve injuries 179


Lateral cutaneous nerve of the forearm

(from musculocutaneous N.)
Medial cutsaneous nerve
of forearm

Superficial branch of radial nerve Palmer cutaneous

branch of ulnar nerve.


Palmer cutaneous branch of

median nerve.
Palmer digital brs. of
ulnar nerve
Palmer digital branches of 
median nerve

Fig. 147: Cutaneous innervation

of the palmer aspect of hand

Lateral cutaneous nerve of the forearm
(from musculocutaneous N.)
Medial cutsaneous nerve of
forearm 
 Posterior cutaneous nerve of
forearm (from radial nerve)

Division between ulnar and radial

nerve innervation on dorsum of Superficial branch and
hand is variable. Sometimes dorsal digital brs. of
rd
aligns with the middle of the 3 radial nerve
th
digit instead of the 4 digit.

Dorsal branch and dorsal

digital brs. of ulnar nerve

Proper palmer digital

brs of median nerve

Fig. 148: Cutaneous

Proper palmer digital brs innervation of the
of ulnar nerve
dorsal aspect of hand



 Cutaneous nerve supply & nerve injuries 180

SEGMENTAL NERVE SUPPLY OF UPPER LIMB
(Figs. 149, 150)

Fig. 149: Anterior view of Upper limb Fig. 150: Posterior view of upper limb
 Cutaneous nerve supply & nerve injuries 181

NERVE INJURIES

Brachial Plexus Injuries

A- Upper trunk injury (Duchenne-Erb's paralysis): it is also called

"Porter's tip deformity" (Figs.151-a, b, c).
- Cause: it may result from excessive displacement of the head to one side
and depression of the shoulder on the other side leading to excessive
traction or even tearing of C5,6 roots of the plexus. This may occur in
infants during delivery as a birth injury.
- Results
1. Motor effect:.
a) The shoulder is:
- Adducted: Due to paralysis of deltoid and supraspinatus.
- Medially rotated: Due to paralysis of infraspinatus and teres
minor.
b) The elbow is extended due to paralysis of biceps and the
greater part of brachialis.
c) The forearm is pronated due to paralysis of biceps.
2. Sensory effect: loss of sensation on the lateral side of the upper
limb.


(A) (B) (C)





Fig. 151: (A & B) showing excessive increase in the angle between head & shoulder
and (C) showing Erb's paralysis"Porter's tip deformity" of left upper limb
 Cutaneous nerve supply & nerve injuries 182

B- Lower trunk injury (Klumpke's Paralysis): (Fig. 152-a,b,c)
- Cause: it may result from:
 Excessive abduction of the arm leading to excessive traction or
tearing of C8 and T1 root of the brachial plexus. This may occur in
the case of a person falling from a height clutching at an object to
save himself or traction of the arm of an infant during delivery.
 Cervical rib.
 Malignant lower deep cervical lymph nodes.

- Results:
1. Motor effect: The fibers of C8 and T1 are mainly distributed through
the median and ulnar nerves to the lumbricals and interossei, so injury
leads to:
- claw hand: hyperextension of the metacarpophalangeal joints (due
to the unopposed action of the extensor digitorum by lumbricals
and interossei) and flexion of interphalangeal joints (due to the
unopposed action of the flexor digitorum superficialis and
profundus by lumbricals and interossei)
- Loss of abduction and adduction of the fingers.
2. Sensory effect: loss of sensation on the medial side of the arm and
forearm as well as of the medial 1/3 of the palm of the hand and the
medial one and half fingers.

Fig. 152: (A & B) showing excessive abduction of the upper

limb and (C) showing Claw Hand deformity

(A) (B)  (C)


 Cutaneous nerve supply & nerve injuries 183

Axillary nerve injury
- Cause: Axillary nerve injury is frequent in:
1. Dislocation of the shoulder joint.
2. Fracture surgical neck of humerus.
3. Pressure of a badly adjusted crutch to the armpit.

- Results:

1. Motor effect:
- Impaired abduction of shoulder due to paralysis of deltoid.
- Flat shoulder (loss of the rounded contour) due to wasting of the
deltoid muscle.
2. Sensory effect:
- Patch of sensory loss over the lower half of deltoid.

Long thoracic nerve injury

- Cause: It may be injured during the surgical procedure of radical
mastectomy.

- Results (Fig. 50):

1. Winging of the scapula.
2. Difficulty in raising the arm above the head.
3. Difficulty in protraction of the shoulder girdle.
 Cutaneous nerve supply & nerve injuries 184

Ulnar nerve injury
- Causes:
 Posterior to the medial epicondyle of the humerus: fracture, dislocation or
compression of the elbow joint.
 In the cubital tunnel formed by the tendinous arch connecting the
humeral and ulnar heads of the flexor carpi ulnaris: compression
 At the wrist: Cut or stab wounds.

- Results (Figs. 153, 154, 155):

1. Motor effect:
A. Effect of injury at the wrist:
 Partial claw hand
Extension of metacarpo-phalangeal joints of the 4th and 5th
fingers and flexion of their interphalangeal joints due to
paralysis of their lumbricals and interossei. The corresponding
joints of the 2nd and 3rd fingers are less affected because their
lumbricals are intact as they are supplied by the median nerve.
 Loss of abduction and adduction of the fingers due to paralysis
of the interossei. The patient is unable to grip a piece of paper
placed between the fingers.
 Loss of adduction of the thumb due to paralysis of the adductor
pollicis. The patient is unable to grip a piece of paper placed
between the thumb and index.
 Flattening of the hypothenar eminence due to wasting of the
hypothenar muscles and hollowing between the metacarpal
bones on the dorsum of the hand due to paralysis of the
interossei.

B. Effect of injury above or at the elbow:

 Clawing of the hand becomes less apparent in the 4th and 5th
fingers due to paralysis of the medial half of the flexor
digitorum profundus.
 Radial deviation of the hand due to paralysis of the flexor carpi
ulnaris.
 Loss of abduction and adduction of the fingers.
 Loss of adduction of the thumb.
 Flattening of the hypothenar eminence and hollowing between
the metacarpal bones on the dorsum of the hand.
2. Sensory effect:
A. Effect of injury at the wrist:
The ulnar nerve and its palmar cutaneous branch are usually
affected leading to loss of sensation over the medial 1/3 of the
palm and the palmer surface of the medial 1 1/2 fingers.
B. Effect of injury above or at the elbow:
Loss of sensation over the medial 1/3 of the palm and the medial 1
1/2 fingers both anteriorly and posteriorly.
 Cutaneous nerve supply & nerve injuries 185


Fig. 153: Claw Hand deformity




Fig. 154: Weakness then loss of abduction & Fig. 155: sensory loss in ulnar
adduction of the fingers in ulnar nerve palsy nerve palsy
 Cutaneous nerve supply & nerve injuries 186

Median nerve injury
- Cause:
 Above the elbow: supracondylar fracture of the humerus.
 Pronator syndrome: it is a nerve entrapment syndrome caused by
compression of the median nerve near the elbow between the 2 heads of
the pronator teres as result of trauma, muscular hypertrophy or fibrous
bands
 At the wrist:
- Cut or stab wounds.
- Carpal tunnel syndrome: it is a compression of the median nerve
while passing through the carpal tunnel. This may be caused by
Inflammation of synovial sheaths of flexor tendons, arthritic
changes of the intercarpal joints, osteophytes of the carpal bones,
dislocation of lunate bone or accumulation of fluid as blood or pus
in the carpal tunnel.

- Results (Figs. 156, 157):

1. Motor effect:

A. Effect of injury at the wrist:

 Loss of opposition of the thumb
 The thumb is laterally rotated so that the 1st metacarpal bone
becomes parallel to the others due to loss of the tone of the
opponens pollicis.
 The thumb is adducted due to the intact adductor pollicis and
paralysis of the abductor pollicis (Ape or Monkey’s hand).
 Wasting of thenar muscles with flattening of the thenar
eminence

B. Effect of injury above the elbow:

 Loss of opposition of the thumb
 The thumb is laterally rotated so that the 1st metacarpal bone
becomes parallel to the others
 The thumb is adducted
 Ape's or Monkey’s hand
 Loss of pronation (due to paralysis of both pronator teres and
quadratus) and the forearm is kept in supine position.
 Ulnar deviation of the hand due to paralysis of the flexor carpi
radialis.
 Weak flexion of the wrist due to paralysis of most of its flexors.
 Loss of flexion of the interphalangeal joints of the index and
middle phalanges due to paralysis of flexor digitorum
superficialis and the lateral half of the profundus. When the
patient tries to make a fist, the index and middle fingers tend
to remain straight (pointing fingers).
 Cutaneous nerve supply & nerve injuries 187

 Loss of flexion of all joints of the thumb due to paralysis of both
flexor pollicis longus and brevis.

2. Sensory effect:

A. Effect of injury above the wrist:

Loss of sensation over the lateral 3 1/2 fingers (their palmar
aspects and the distal parts of their dorsal aspects). If the palmar
cutaneous branch is included in the injury, there will be loss of
sensation over the lateral 2/3 of the palm. In carpal tunnel
syndrome, there will be paresthesia over the lateral 3 1/2
fingers.

B. Effect of injury above the elbow:

Loss of sensation over the lateral 3 1/2 fingers and the lateral 2/3
of the palm






Fig. 156: Ape Hand deformity in Fig. 157: Atrophy of thenar
median nerve palsy muscles due to long standing
compression of median nerve
 Cutaneous nerve supply & nerve injuries 188

Radial nerve injury
- Cause:
 Fracture shaft of humerus may injure the radial nerve while passing in the
spiral groove (Fig. 158).
 The radial nerve may be injured in the axilla by pressure of a badly
adjusted crutch into the armpit or by a drunkard falling asleep with one
arm over the back of a chair (Saturday night palsy)
 The posterior interosseous nerve may be injured in fracture head, neck or
upper part of the shaft of the radius or even downward dislocation of the
head of the radius.

- Results (Figs. 158, 159, 160):

1. Motor effect:
 Injury of radial nerve above the elbow leads to wrist drop and
fingers drop due to paralysis of all extensors of the wrist and
fingers. This is very disabling because it is impossible to
perform a firm grip while the wrist is flexed.
 Injury of the radial nerve impairs the extension of the elbow
against resistance due to affection of the triceps as well as it
leads to failure of supination of the extended forearm

 In case of posterior interosseous nerve injury, there is only

fingers drop without wrist drop due to the intact extensor carpi
radialis longus which, alone, can maintain the extension of the
wrist

2. Sensory effect: (according to the level of injury of the radial

nerve)
 Patch of sensory loss over the lower half of deltoid.
 A small area of complete loss of sensation on the dorsum of
the hand between the 1st and 2nd metacarpal bones.
Restriction of sensory loss to this area is due to the overlap of
sensory innervation by adjacent nerves in the areas of radial
distribution.
 Paresthesia over the posterior surface of arm, forearm, lower
part of the lateral side of the arm, lateral 2/3 of the dorsum of
the hand and the posterior surfaces of the proximal phalanges
of the lateral 3 1/2 fingers.
 Cutaneous nerve supply & nerve injuries 189


Fig. 158: radial nerve

injury in humeral
fracture with wrist drop

Fig. 160: Areas of paresthesia of

the upper limb in high-level
injury of radial nerve


Fig. 159: Area of pure sensory loss in
radial nerve palsy
 Cutaneous nerve supply & nerve injuries 190

Formative assessment

I. Describe the deformity resulting from injury of upper trunk of

brachial plexus.
II. Explain claw hand deformity of ulnar nerve injury.
III.M.C.Q:
1. Loss of finger's abduction and adduction results from lesion of
which one of the following nerves?
a. Ulnar nerve.
b. Median nerve.
c. Radial nerve.
d. Musculocutaneous nerve.
2. Winging of scapula follows paralysis of:
a. Serratus anterior muscle.
b. Deltoid muscle.
c. Trapezius muscle.
d. Teres major muscle.
3. Ape's-like hand deformity results from following injury of which
one of the following nerves?
a. Axillary nerve.
b. Median nerve.
c. Ulnar nerve.
d. Radial nerve.
4. Wrist drop deformity results from injury of which one of the
following nerves?
a. Ulnar nerve.
b. Median nerve.
c. Radial nerve.
d. Axillary nerve.
5. Inability to abduct the arm from 15 to 90 degrees is due to injury
of:
a. Radial nerve.
b. Long thoracic nerve (nerve to serratus anterior).
c. Musculocutaneous nerve.
d. Axillary nerve.

 Joints of upper limb 191

CHAPTER 11

ILO’s
By the end of the lectures, the student should be able to:

1. Recognize the type of each joint of the upper limb.

2. Describe the ligaments of each joint.
3. Determine the movements of each joint.
4. Describe the muscles acting on each joint.
5. Determine the stability of each joint.
6. Interpret some clinical problems resulted from dislocation of each joint
to their relation to important nerves or arteries.

JOINTS OF THE UPPER LIMB

Joints of shoulder girdle

1. Acromio-Clavicular Joint (Fig. 161):

- Type: synovial, plane variety.

- Bony parts (articular surfaces):
 Acromial end of clavicle.
 Medial margin of acromion.
- Articular disc: the joint usually contains an articular disc, which divides
its cavity into 2 incomplete compartments (medial and lateral).
- Capsule: it completely surrounds the joint and is strengthened above by
acromio-clavicular ligament.
- Arterial supply: supra-scapular and thoraco-acromial arteries.
- Nerve supply: supra-scapular and lateral pectoral nerves.
- Functions:
 It shares a little in the movements of shoulder girdle.
 It shares in transmitting forces from the upper limb to the clavicle;
but the main medium transmitting forces from the upper limb to
clavicle is the coraco-clavicular ligament.

* Coraco-clavicular ligament
It is very strong bond connecting the clavicle with the coracoid process
of the scapula (Fig. 161).
- Parts: it consists of two incompletely separated parts:
A. Trapezoid part
 Forms the anterolateral part of the coraco-clavicular ligament.
 Joints of upper limb 192


 Quadrilateral in shape; its posterior border is joined with the

conoid part.
 Attached below to the upper surface of the coracoid process and
above to the trapezoid line on the lower surface of the lateral
third of the clavicle.

B. Conoid part
 Forms the posteromedial part of the coraco-clavicular ligament.
 A dense band of fibrous tissue.
 Attached below to the upper and posterior aspect of the bend of
the coracoid process of scapula and above to the conoid
tubercle of clavicle.

- Function:
 It limits the movements of acromio-clavicular joint and prevents
dislocation of the acromial end of the clavicle.
 It is the main medium by which the scapula and the upper limb
are suspended from the clavicle. If the clavicle is fractured
medial to the attachment of coraco- clavicular ligament, the
upper limb drops.

2. Sterno-clavicular Joint (Fig. 162):

- Type: Synovial; modified saddle joint.

- Bony parts (articular surfaces):
Clavicular notch of manubrium sterni and first costal cartilage.
Sternal (medial) end of the clavicle.
- Intra-articular disc:
 It is a flat circular disc of fibro- cartilage interposed between the
articulating surfaces of the sternum and the clavicle.
 It is attached by its circumference to the fibrous capsule.
 It divides the joint cavity into two separate cavities.
 Functions:
l. It absorbs the forces transmitted to the joint from the shoulder region
through the clavicle.
2. It prevents dislocation of the sternal end of the clavicle.

- Capsule:
Surrounds the joint completely. It is thicker in front and behind, but is thin
above and below.
- Ligaments:
1. Anterior sterno-clavicular ligament:
It covers the anterior surface of the joint. It is attached laterally to
the front of the sternal end of the clavicle and medially to the front
of the upper part of manubrium sterni.
 Joints of upper limb 193


Capsule of acromio- Clavicle

clavicular joint
Trapezoid part of
coraco-clavicular lig.
Acromion
Conoid part of
Coracoacromial coracoclavicular lig.
ligamernt
Suprascapular lig. &
foramen
Capsule of
shoulder joint
Scapula

Acromioclavicular joint

Fig. 161: Anterior view of acromioclavicular joint 

Anterior sternoclavicular lig.

Costoclavicular ligament
Interclavicular ligament
Clavicle

Articular disc

Manubrium sterni

Fig. 162: Anterior view of sternoclavicular joint
 Joints of upper limb 194

2. Posterior sterno-clavicular ligament:
 It covers the posterior surface of the joint. It is attached
laterally to the back of sternal end of clavicle and medially to
the back of upper part of manubrium sterni.
3. Interclavicular ligament:
It passes from the upper aspect of the sternal end of one clavicle
to that of the other, crossing above the upper margin of
manubrium sterni and is attached to it.
4. Costo-clavicular ligament:
 It is a short ligament with an inverted conical shape.
 It is ttached below to the upper aspect of 1st costo-chondral
junction and above to the margins of the impression o the lower
surface of medial end of the clavicle.
 This ligament prevents excessive elevation and protraction of
the clavicle (the same function of subclavius muscle, which acts
as a dynamic ligament).
- Stability: it is a stable joint. Its strength depends on its ligaments and
the intra-articular disc.
- Arterial supply:
1. Supra-scapular artery 2. Internal mammary artery
- Nerve supply:
1. Medial supra-clavicular nerve 2. Nerve to subclavius
* Movements of the shoulder girdle (Figs. 163, 164):
Movements of the shoulder girdle occur at both acromioclavicular and
sternoclavicular joints. The scapula is the main element of the girdle,
which moves on the clavicle at the acromioclavicular joint, but the
movement at this joint is limited. However, the movement at the
sternoclavicular joint increases the range of movement of the scapula.
A. Elevation
1. Upper fibers of trapezius 2. Levator scapulae
3. Rhomboid majpr and minor
B. Depression
1. Pectoralis minor
2. Inferior fibers of trapezius
C. Rotation up (glenoid cavity faces upwards):
1. Upper and lower fibers of trapezius
2. Serratus anterior
D. Rotation down (glenoid cavity faces downward):
1. Levator scapulae 2. Rhomboideus major
3. Rhomboideus minor
E. Protraction (pulling forwards):
1. Serratus anterior
2. Pectoralis minor
F. Retraction (pulling backwards towards the vertebrae):
1. Middle fibers of trapezius 2. Rhomboideus major
3. Rhomboideus minor
 Joints of upper limb 195






 Joints of upper limb 196

Shoulder joint
- Type: synovial, polyaxial (ball and socket)

- Bony parts (articular surfaces) (Figs. 165, 166):

The head of humerus and the glenoid cavity deepened by the labrum
glenoidale.
 Labrum glenoidale: it is a fibrocartilaginous rim, triangular on cross
section with its free edge thin and sharp, while its base is fixed to the
circumference of the glenoid cavity. It deepens and widens the articular
socket and protects the edges of the glenoid cavity.

- Fibrous capsule:
 Attachment (Fig.167):
1. Medially: it is attached to the circumference of glenoid cavity
beyond the labrum glenoidale. It encroaches above onto the root
of the coracoid process to include the supra-glenoid tubercle
within the capsule.
2. Laterally: it is attached to the anatomical neck of humerus except
below where it descends for half an inch onto the medial side of
the surgical neck of the humerus. This means that this part of
the surgical neck is intracapsular.

 Perforations of the capsule (Fig. 168) :

There are 2-3 perforations in the capsule:
1. Anterior perforation: it is situated just below the coracoid process
and through which the joint cavity communicates with the
subscapular bursa.
2. Lateral perforation: it is situated antero-laterally between the
greater and lesser tubercles for the passage of the tendon of long
head of biceps.
3. Posterior perforation (not constant): it is situated posteriorly and
and may communicate with the bursa deep to the tendon of the
infraspinatus muscle.

- Synovial membrane:
1. It lines the fibrous capsule and it is reflected to cover the intracapsular
non-articular bony parts.
2. It is continuous with the subscapular bursa through the anterior
perforation of the capsule.
3. It envelops the tendon of long head of biceps forming a tubular
sheath, which comes out of the capsule through the lateral perforation.
 Joints of upper limb 197

Coracoacromial lig.
Head of
humerus

Glenoid
labrum
Glenoid
cavity Glenoid Coracoid pr.
cavity Coracohumeral

lig
Fig. 165: Articular surfaces of Long head
shoulder joint (Posterior view) of biceps
Long head of
Acromion Clavicle triceps tendon

Lateral border of scapula

Coracoa-
cromial Lig.

Inferior angle of scapula 

Anterior perforations 
Lateral perforation
Long head of biceps tendon

Fig. 167: Perforations of the capsule Fig. 166: articular surfaces of shoulder joint
of shoulder joint (Anterior view) (Lateral view)

Gleno-humeral
ligaments

Clavicle

Fig. 168: ligaments of shoulder joint

 (Ant. View) 
 Joints of upper limb 198

- Bursae related to the joint (Figs.168, 169, 170):
1. Subscapular bursa: lies deep to the subscapularis, between it and the
front of the capsule of the shoulder joint.
2. A bursa deep to the tendon of infraspinatus muscle: it lies between it
and the back of the capsule.
3. Subacromial bursa: it lies between the deltoid and the capsule. It is
prolonged under the acromion and the coraco-acromial ligament
separating them from tendon of supraspinatus. It does not
communicate with the joint cavity.
4. A bursa situated between the coracoid process and the capsule.
5. A bursa situated on the upper surface of the acromion (subcutaneous).

- Ligaments (Fig. 168):

1. Three gleno-humeral ligaments (are weak):
 Strengthen the anterior surface of the capsule.
 Extend from the anterior margin of the glenoid cavity to the
lesser tuberosity and anatomical neck of the humerus.
2. Coraco-humeral ligament (stronger):
 Strengthens the upper part of the capsule.
 Extends from the coracoid process obliquely downwards and
laterally immediately above the capsule to be attached to the
upper border of the greater tuberosity of the humerus.
3. Transverse humeral ligament:
 A broad band passing from lesser to greater tuberosity of the
humerus converting the inter-tubercular groove into canal.
 It acts as a retinaculum for the tendon of long head of biceps.
- Intra-capsular structures (Fig.171):
1. Tendon of long head of biceps.
2. Head of humerus and medial part of its surgical neck.
3. Labrum glenoidale.
4. Glenoid cavity and supra-glenoid tubercle.
5. Synovial membrane.

- Stability:
A. The shoulder joint is weak. It is unstable, not secure and is easily
dislocated because:
 The fitting of its bony parts together is not good, as the head of
the humerus is very large compared with the small, shallow, poor
socket formed by the glenoid cavity.
 The capsule and its ligaments are weak and lax.
 The capsule is not directly suppored by any muscle from below
B. The joint is supported by muscles ( Fig.171) as follow:
 Above: by tendons of the supraspinatus and long head of biceps
 In front: by tendon of the subscapularis
 Joints of upper limb 199

Supraspinatus Fig. 169: Subacromial bursa
muscle and its extension (Ant. View)

Subsacpularis muscle

Subdeltoid bursa (subacromial) with extension

under acromion & coracoacromial lig.
Deltoid muscle
Fold of the inferior part of the capsule
 of shoulder joint

Acromion Capsule
Supraspinatus tendon
Clavicle & acromio-
clavicular joint
Subacromial bursa
Synovial membrane
Glenoid labrum

Deltoid muscle
Glenoid cavity of scapula

Fig.170: Coronal section

Capsular fold with axillary recess of synovial m.
in the shoulder joint

Supraspinatus tendon

Coracoacromial lig. Coracoid process
Coraco-humeral ligament
Acromion

Biceps tendon (long head)

Subacromial bursa

Superior gleno-humeral
Infraspinatus tendon
ligament
Glenoid cavity
Subscapularis tendon
Communication with
bursa of subscapularis

Middle gleno-humeral
Teres minor tendon
ligament

Synovial membrane (cut)

Inferior gleno-humeral ligament

Fig. 171: Shoulder joint (Opened)


 Joints of upper limb 200


 Behind: by tendons of the infraspinatus and teres minor.

- The tendons of supraspinatus, subscapularis, infraspinatus and
teres minor muscles are all intimately related to the fibrous
capsule and form "the rotator muscle cuff", which reinforce
the capsule and provide an active support for the joint during
movement.
- The deltoid muscle covers the joint in front, behind and laterally.
 Below: the joint is not supported by any muscle from below where
the capsule is lax and forms a fold, which bulges downwards into the
upper part of the axilla (Figs.169, 170) where it is directly related to
axillary nerve and posterior circumflex humeral artery. This fold is
stretched when the arm is fully abducted. Long head of triceps
supports the capsule from below when the arm is abducted.
C. The joint is protected from above by Coraco-acromial arch,
which is formed as follows:
 Coraco-acromial ligament (Figs.,166,167) is a strong flat triangular
ligament. Its apex is attached to the tip of the acromion while its
base is attached to the lateral margin of the upper surface of the
coracoid process.
 This ligament together with the two processes form the coraco-
acromial arch, which lies immediately above the shoulder joint
forming a secondary socket for the head of the humerus supporting it
from above.

- Arterial supply: from the anterior and posterior circumflex humeral

and suprascapular arteries.
- Nerve supply: from suprascapular, axillary and lateral pectoral nerves.
- Movements: The shoulder joint is structurally weak and has a loose
and lax capsule. This construction permits a very wide range of
movement but at the expense of the stability of the joint.
1. Flexion:
1. Clavicular head of pectoralis major
2. Anterior fibers of deltoid
3. Coraco-brachialis
N.B. The movement is assisted by the long head of biceps.
2.Extension:
1. Posterior fibers of deltoid
2. Teres major
3. Latissimus dorsi
4. Subscabularis
N.B. The sternocostal head of pectoralis major extends the flexed arm.
C. Abduction:
1. Supra-spinatus
2. Middle (acromial) fibers of deltoid
 Joints of upper limb 201


(Anterior view)

Fig. 172: Articular surfaces of elbow joint


Line of attachment of
capsule of elbow joint

Superior radio-ulnar joint


Fig. 173: Attachments of capsule of elbow Fig. 174: Attachments of capsule of elbow
joint (Anterior view) joint (Posterior view)
 Joints of upper limb 202

D. Adduction:
1. Pectoralis major 2. Teres major 3. Latissimus dorsi
4. Coraco-brachialis 5. Subscapularis 6. Infraspinatus
7. Teres minor
E. Medial rotation:
1. Pectoralis major 2. Teres major 3. Latissimus dorsi
4. Anterior fibers of deltoid. 5. Subscapularis
F. Lateral rotation:
1. Infra-spinatus. 2. Posterior fibers of deltoid.
3. Teres minor.
G. Circumduction: it is a combination of the above-mentioned
movements.
 Mechanism of abduction of the shoulder
 Supraspinatus initiates abduction from 0-15 or 18 degrees.
 The middle (acromial) fibers of deltoid then continue abduction to 90 or
100 degrees. After this range, the head cannot move any further
because it impinges on coraco-acromial ligament.
 Raising the arm above the head from 90-180 degrees, the scapula
rotates over the chest wall so that the glenoid cavity becomes directed
upwards, i.e., it is a movement of the shoulder girdle. This is done by
trapezius and serratus anterior muscles.

N.B. During abduction of the arm, there are simultinaneous movements of the
◦
shoulder joint and shoulder girdle, so that every 10 of abduction at the shoulder joint
◦
there is an addition of 5 due to an abward rotation of the scapula; this is continuous
◦
until the range of 90 of abduction when the whole movement takes place by upward
rotation of the scapula.

Elbow joint

- Type: synovial, uniaxial (hinge) joint.

- Bony parts (articular surfaces) (Fig. 172):

 Proximally: the condyle of humerus (trochlea and capitulum).
 Distally: trochlear notch of ulna and head of radius, where trochlea
articulates with trochlear notch of ulna and capitulum articulates with
upper circular surface of the head of radius.

- Capsule (Figs. 173, 174): it is attached to the lower end of humerus and
the upper end of ulna and radius as follows:
 Above and in front: it is attached to the humerus just above the
coronoid and radial fossae and extends to the root of the medial and
lateral epicondyles.
 Joints of upper limb 203


Fig. 175: Radial collateral ligament of elbow joint (Lateral view)



Fig. 176: Ulnar collateral ligament of elbow joint (Medial view)

 Joints of upper limb 204


 Above and behind: it is attached to the lower end of the humerus,

just above the olecranon fossa
 Below: the capsule is attached to the margins of the olecranon and
the annular ligament, which encircles the head of the radius.
N.B. The elbow and the superior radioulnar joint have a common capsule.
The capsule is thin in front and behind but it is thick on each side due to
the presence of the strong collateral ligaments.

- Ligaments (Figs. 175, 176):

1. Medial (ulnar) collateral ligament: fan-shaped and is attached
above to the medial epicondyle and below to the medial margin of
trochlear notch (medial margin of olecranon and coronoid
processes). It prevents abduction of the elbow joint.
2. Lateral (radial) collateral ligament: is a stong triangular ligament. It
is attached above, by its apex, to the lateral epicondyle and
below, by it base, to the outer surface of annular ligament. It
prevents adduction.

- Intra-capsular structures (Figs. 173,174): they enclude the

articular surfaces as well as the coronoid, radial and olecranon fossae
and the synovial membrane, which iscontinuous with that of superior
radio-ulnar joint. The medial and lateral epicondyles are extra-capsular.

- Arterial supply: from the anastomosing arteries around the elbow.

- Nerve supply: from musculo-cutaneous, radial, ulnar and median

nerves.

- Movements:
1. Extension: triceps muscle assisted by anconeus
2. Flexion: mainly by Brachialis and biceps. It is assisted by brachio-
radialis and superficial flexors of the forearm.
 Joints of upper limb 205

RADIO-ULNAR JOINTS

1. Superior radio-ulnar joint

- Type: synovial, uniaxial (pivot) joint.

- Bony parts (articular surfaces) (Figs. 177,178): the circumference of

the head of radius rotates against the radial notch of ulna (on the
lateral aspect of the coronoid process). At any time in pronation or
supination only one quarter of the circumference of the head of radius
articulates with the radial notch of ulna. The remaining three quarters
of the head articulates with the annular ligament.

- Capsule: it is continuous above with the capsule of the elbow joint. Their
joint spaces are continuous together.

- Synovial membrane: The synovial membrane is a downward

prolongation of the synovial membrane of the elbow joint.

- Ligaments (Figs. 177, 178, 179)

1. Annular ligament: it is about three quarters of osseofibrous ring
attached to the anterior and posterior margins of the radial notch of
ulna and encircles the head of radius. It gives attachment to the
capsule and lateral collateral ligament of the elbow joint. It is
slightly narrower below than above and this prevents the head of
radius from being dislocated downwards.
2. Quadrate ligament: it is quadrangular band connecting the lower
margin of the radial notch of the ulna to the medial aspect of the
neck of radius just above its tuberosity. It lies just below the joint,
thus closing its cavity from below.

2. Inferior radio-ulnar joint

- Type: Synovial, uniaxial (pivot) joint.

- Articular surfaces (Fig. 180):

a. The head of ulna
b. The ulnar notch of radius.
c. The articular disc:
 Joints of upper limb 206

 It is a fibrocartilaginous triangular disc attached by its apex into a
depression between the styloid process and the inferior surface of the
ulnar head while the base is attached to lower edge of the ulnar notch
of radius.
 Its upper surface is concave and articulates with the head of ulna. Its
lower surface is also concave and it articulates with the lunate bone. It
separates the cavity of inferior radio-ulnar joint from that of the wrist
joint (i.e., the synovial membrane of the inferior radio-ulnar joint is
separated from that of wrist joint by the disc).
- Capsule: it is slightly thickened anteriorly and posteriorly while above it
is lax to allow for the wide movement of pronation.
- Synovial membrane (Fig. 180): it lines the capsule and projects
upwards as a small pouch called recessus sacciformis between the
radius and ulna in front of the interosseous membrane.

Pronation and Supination

- Joints: they occur at the superior and inferior radio-ulnar joints (pivot
joints).
- Axis of movement (Fig. 181): it is a vertical axis which passes from the
center of head of radius above to the rough impression of the head of
ulna below (attachment of the apex of the articular disc).
- Mechanism of movement:
 The head of radius simply rotates within the ring formed by the radial
notch of ulna and the annular ligament (at the superior radio-ulnar
joint).
 The shaft of radius swings while the shaft of ulna remains relatively
fixed.
 At the inferior radio-ulnar joint: the lower end of the radius and the
articular disc (below the head of ulna) rotate around the head of ulna;
the radius carries the hand with it. The movement is in the form of a
circle, the centre of which is at the attachment of the apex of the
articular disc to the root of styloid process of ulna (i.e., the head of
ulna acts as a fixed bone around which the lower end of the radius
rotates).
a. In Supination:
 The radius and ulna lie parallel to each other.
 The palm faces forwards.
 The thumb is directed laterally.
 The interosseous membrane is tense.
b. In Pronation:
 The shaft of radius lies across the front of the shaft of ulna so that
the lower end of radius lies now on the medial side of the ulna.
 The hand moves with the radius so that the palm now looks
backwards.
 Joints of upper limb 207


Fig. 177: Annular ligament

(Anterior view) 


Head of
radius

Annular
ligament
Radius Ulna

Quadrate ligament

 Fig. 179: Quadrate ligament of

Fig. 178: Superior radioulnar joint (Ant. View) superior radioulnar joint (Ant. View)

Recessus sacciformis

Head of ulna


Fig. 180: Inferior radioulnar joint (coronal section)
 Joints of upper limb 208

 The thumb is now directed medially.
 The interosseous membrane becomes lax.
 The carrying angle at the elbow disappears

- Muscles working on the radioulnar joints:

A. Supinators: are the biceps (the main supinator of the flexed
elbow) and the supinator, in addition to brachioradialis, which puts
the forearm in the midprone position.
B. Pronators: are the pronator teres and pronator quadratus, in
addition to brachioradialis, which puts the forearm in the
midprone position.

 N.B:
In general, supinators are more powerful than the pronators.
Biceps is the most powerful supinator during flexion of elbow while supinator
is the main supinator during extension of the elbow.

Axis of
movement

Head of radius
Biceps tendon
Oblique cord

Radius

Interosseous
membrane

Ulna


Supination  Pronation 

Fig. 181: Movements of radioulnar joints Fig. 182: Interoseous membrane

(Anterior view) (Anterior view)
 Joints of upper limb 209

Interosseous membrane
In addition to superior and inferior radio-ulnar joints, the radius and ulna are
also joined by a fibrous membrane called interosseous membrane.

- Attachment (Fig. 182):

 Laterally: it is attached to the interosseous border of radius.
 Medially: it is attached to the interosseous border of ulna.
 Above: it ends at a free border 2.5cm below the radial tuberosity.
 Below: it blends with the capsule of inferior radio-ulnar joint.

- Direction of fibers: the fibers of the interosseous membrane run

obliquely downwards and medially from radius to ulna.

- Functions:
1. Increases the area (both in front and at the back) for the origin of
numerous
muscles of the forearm.
 Muscles which take origin from its anterior surface:
a. Flexor pollicis longus
b. Flexor digitorum profundus
 Muscles which take origin form its posterior surface:
a. Abductor pollicis longus
b. Extensor pollicis longus
c. Extensor pollicis brevis
d. Extensor indicis
2. The radius receives forces from the hand. The interosseous membrane,
due to the direction of its fibers, transmits forces from radius to
ulna, which, in turn, transmits forces upwards to the humerus.

- Relations:
 The anterior interosseous nerve and vessels lie on its anterior surface.
 The anterior interosseous artery pierces it 5 cm above its lower end.
 The posterior interosseous vessels pass backwards above its upper
border.
 Pronator quadratus crosses in front of its lower part.
 Muscles attached to its anterior and posterior surfaces.
 Joints of upper limb 210

Wrist joint
- Type: synovial, biaxial (ellipsoid) joint.

- Bony parts (articular surfaces) (Fig. 183):

A. Proximal articular surface: has an ellipsoid outline with a transverse
diameter of about 5 cm. and an antero-posterior diameter of about 2 cm.
It is slightly concave in both directions. It is formed by:
 The inferior surface of lower end of radius, which is divided into a
lateral triangular part to articulate with the scaphoid and a medial
quadrilateral part to articulate with the lunate.
 The articular disc of inferior radio-ulnar joint, which lies below the
head of ulna (separating it from the triquetral bone).
B. Distal articular surface: is formed of three carpal bones; from lateral
to medial they are scaphoid, lunate and triquetral bones.
 Scaphoid and lunate lie below the radius.
 Triquetral lies below the articular disc below the head of ulna.
 These three bones form together an oval surface, which is convex in
all directions.
N.B. The ulna does not come in direct contact with the carpal bones and
does not share in the formation of the wrist joint because of the presence of
the articular disc of cartilage below the head of ulna. Therefore, the wrist
joint is called radio-carpal joint.

- Capsule: The capsule is attached to the margins of the articular surfaces.

- Ligaments (Figs. 184, 185):

 Radial collateral ligament: extends from the tip of styloid process of
radius to lateral side of scaphoid and trapezium.
 Ulnar collateral ligament: extends from end of styloid process of ulna
to medial side of triquetral and pisiform bones.
 Palmar radiocarpal ligament: extends obliquely and medially from
anterior margion of lower end of radius and its styloid process to
anterior surface of scaphoid, lunate and truquetral bones.
 Palmar ulnocarpal ligament: extends from the base of styloid process
of ulna and anterior margin of the articular disc to the anterior surface
of lunate and triquetral bones
 Dorsal radiocarpal ligament: extends downwards and medially from
the posterior surface of lower end of radius to dorsal surface of
scaphoid, lunate and triquetral bones, it is weaker than the palmar one.
 Joints of upper limb 211


Pisiform

Lunate Flexor carpi radialis

Scaphoid
Triquetrum

Synovial membrane

Styloid process of Styloid process of

ulna radius

Articular disc Inferior surface of

radius
Ligamentous
anterior border of
articular disc

Fig. 183: Wrist joint (Opened) showing articular surfaces (Anterior view)


Ulna Radius
Radius Ulna
Dorsal radiocarpal
ligament
Scaphoid
tubercle Radial collateral
Pisiform ligament
Trapezium


Palmar radiocarpal Palmar ulnocarpal
ligament ligament

Ulnar collateral ligament

Fig. 184: Ligaments of wrist joint Fig. 185: Ligaments of wrist joint
(Anterior view) (Posterior view)

 Joints of upper limb 212

- Arterial supply: from the arteries forming the anterior and posterior
carpal arterial arches (P.154).

- Nerve supply: by anterior and posterior interosseous nerves.

- Movements:
A. Flexion:
1. Flexor carpi radialis
2. Flexor carpi ulnaris
3. Palmaris longus
4. Flexor digitorum superficialis and profundus.
5. Flexor pollicis longus

B. Extension:
1. Extensor carpi radialis longus
2. Extensor carpi radialis brevis
3. Extensor carpi ulnaris
4. Extensor digitorum,extensor indicis,extensor digiti minimi.

C. Adduction:
1. Flexor carpi ulnaris
2. Extensor carpi ulnaris

D. Abduction:
1. Extensor carpi radialis longus
2. Extensor carpi radialis brevis
3. Flexor carpi radialis
4. Abductor pollicis longus
5. Extensor pollicis brevis

- Relations:
 Anteriorly: the flexor retinaculum and the structures passing both deep
and superficial to it.
 Posteriorly: the extensor retinaculum and the structures passing deep
to it.
 Postero-laterally: the anatomical snuff-box.
 Joints of upper limb 213


Mid-carpal joint
- Type and Variety (Fig. 186): synovial; modified ellipsoid joint.

- Bony parts (articular surfaces): it is the joint between:

 The proximal row of carpal bones, as one unit.
 The distal row of carpal bones, as the second unit.
- Capsule: it has a common capsule and a common joint cavity.
- Ligaments: the carpal bones are held together rby strong interosseous
ligaments.
- Movements: its movements are complimentary to those of wrist joint but
much more limited. It allows limited flexion, extension, abduction and
adduction (the same muscles as the wrist are concerned).

Carpo-metacarpal joints

1. All the metacarpal bones, except that of the thumb, join the carpus in
such a way that their palmar surfaces look forwards. The metacarpal bone
of the thumb joins the trapezium in such a way that the thumb is rotated
about 90 degrees so that its palmar surface looks medially. The plane of
the thumb lies at right angle to that of the other fingers. This makes the
thumb able to oppose the other fingers.
2. Articular surfaces: the distal row of carpal bones articulate with the bases
of the metacarpal bones in the following manner (Fig.186):
 Trapezium articulates with the 1st metacarpal bone (of the thumb).
 Trapezoid articulates with the 2nd metacarpal bone (of the index).
 Capitate articulates with the 3rd metacarpal bone (of middle finger).
 Hamate articulates with the 4th and 5th metacarpal bones (of the
ring and little fingers).

1. Carpo-metacarpal joint of the thumb

- Type: synovial, biaxial (saddle-shaped joint) (Figs. 187, 188).
- Articular surfaces: the superior surface of rapezium articulates with
the base of 1st metacarpal bone. The articular surface of each bone is
concavo-convex (i.e., concave in one direction and convex in the other
perpendicular direction).
 Joints of upper limb 214

- Movements: it is a relatively freely mobile joint because the 1st
metacarpal bone lies at 90 degree to the plane of palm, in addition to a
loose fibrous capsule. It allows the following movements (Fig. 189):
A. Flexion and extension: occurs in a plane parallel to the palm.
 Flexion:
1. Flexor pollicis longus
2. Flexor pollicis brevis
3. Opponens pollicis
 Extension:
1. Extensor pollicis longus
2. Extensor pollicis brevis
B. Abduction and adduction: in a plane at right angle to the palm.
 Abduction:
1. Aductor pollicis longus
2. Abductor pollicis brevis
 Adduction:
1. Adductor pollicis
2. First palmer interosseous (if exists)
C. Opposition: the thumb is flexed, then rotated medially so that its
palmar surface opposes the palmar surface of any of the other four
fingers.
1. Opponens pollicis (main muscle)
2. Flexor pollicis brevis
3. Adductor pollicis
D. Circumduction: is a combination of the upper four movements.

N.B. The thumb is the most important finger because of its ability to oppose the
other four fingers, performing fine movements.

2. Carpo-metacarpal joints of the medial four fingers

- Type: synovial, plane variety.
- Movement: minimal gliding movement. The little finger has an
opponens muscle which can move its metacarpal bone forwards and
laterally toward the thumb and helps in cupping the hand.

Metacarpo-phalangeal joints

- Type: synovial ellipsoid joints between the convex heads of the metacarpal
bone and the shallow concavities of the bases of the proximal phalanges.

N.B. The metacarpo-phalangeal joint of the thumb is classified as hinge as

abduction and adduction are restricted at this joint.
 Joints of upper limb 215


Inferior radioulnar joint

Radiocarpal (wrist) joint

Ulna Radius
Midcarpal joint

Pisiform
Trapezium
Triquetral
Carpo-metacarpal joint
Carpo-metacarpal of thumb
Hamate
joints
st
1 metacarpal of
thumb

Fig. 186: Joints of the hand (Coronal section)



Fig. 188: Saddle-shaped

Fig. 187: Saddle-shaped joint of the carpo- joint with concavo-convex
metacarpal joint of thumb articular surfaces
 Joints of upper limb 216


Fig.189: Movements of the thumb at the carpo-metacarpal joint

 Joints of upper limb 217

- Movements (Figs. 190, 191):
1. Movements of metacarpo-phalangeal joints of the medial four
fingers:
A. Flexion: by lumbricals, interossei, flexor digitorum superficialis and
profundus.
B. Extension: by extensor digitorum, extensor indicis and digiti
minimi.
C. Adduction: by palmar interossei.
D. Abduction: by dorsal interossei.

N.B
The fingers can be flexed at the metacarpo-phalangeal joints for 90 degrees
but they can be slightly extended beyond the straight line, i.e., slightly
hyperextended.
Abduction and adduction at the metacarpo-phalangeal joints are free when
the fingers are extended but they become gradually limited as the fingers
are flexed until the hand is completely closed, abduction and adduction
become impossible.

2. Movements of metacarpo-phalangeal joint of the thumb:

A. Flexion: by flexor pollicis longus and brevis.
B. Extension: by extensor pollicis longus and brevis.

N.B. It allows only 60 degrees range of flexion and extension. Abduction and
adduction are very much restricted.

Interphalangeal joints
- Type: synovial, uniaxial (hinge) joints.

- Movements (Figs. 192, 193): they allow flexion and extension only.
1. In the medial four fingers:
A. Flexion:
1. Flexor digitorum profundus (acting on both proximal and distal
interphalangeal joints).
2. Flexor digitorum superficialis (acting only on proximal I/P joint).
B. Extension:
1. Lumbricals
2. Interossei
3. Extensor digitorum
4. Extensor indicis
5. Extensor digiti minimi
2. In the thumb:
A. Flexion: Flexor pollicis longus
B. Extension: Extensor pollicis longus
 Joints of upper limb 218



 Joints of upper limb 219

Formative assessment

I) M.C.Q:
1-The principal muscle concerned in lateral rotation of the shoulder:
a. Pectoralis major.
b. Deltoid anterior fibers.
c. Teres major.
d. Teres minor.
2-The ulnar collateral ligament:
a. Attached to the medial epicondyle of the humerus.
b. Attached to the lateral border of coronoid process of ulna.
c. Attached to triceps and flexor carpi radialis.
d. The ulnar nerve passes in front the ulnar collateral ligament.
3- Concerning pronation and supination:
a. Pronation is more powerful than supination.
b. Supination is done by biceps when the elbow is extended.
c. They occur at the elbow joint.
d. The ulna is fixed; the radius is the movable bone.
II) Explain:
1. The shoulder joint is an unstable joint.
2. The shoulder joint has a wide range of movements
 Summary 220

CHAPTER 12
SUMMARY

SUMMARY OF THE WHOLE COURSE OF RADIAL ARTERY

- Beginning: in the cubital fossa, 1 cm below the elbow joint, at the level of neck
of radius as the smaller of the two terminal branches of the brachial artery.

- Course:
 In the forearm: it passes downwards and laterally in the lateral part of the
front of the forearm to reach the wrist.
 At the wrist: it winds backwards round the lateral side of the wrist passing
through the anatomical snuff-box to reach the dorsum of the hand.
 In the hand:
1. In the dorsum of the hand, it descends towards the proximal part of the
1stinterosseous space, where it passes forwards to reach the palm of
the hand.
2. In the palm, it runs medially immediately distal to the bases of the
metacarpal bones as the deep palmar arch.

- Relations
A. In the forearm:
1. Posteriorly: the radial artery lies on the muscles attached to the front
of radius. Thus from above downwards it lies successively on:
 Biceps tendon
 Supinator
 Insertion of pronator teres
 Origin of radial head of flexor digitorum superficialis
 Flexor pollicis longus
 Pronator quadratus
 Lower end of radius, directly on the bone.
2. Laterally:
 Brachioradialis (in the upper and lower part of forearm)
 Superficial radial nerve (in the middle 1/3 of forearm)

3. Medially:
 In the upper third: pronator teres muscle.
 In the lower two thirds: tendon of flexor carpi radialis muscle.
4. Anteriorly:
 In the upper part: the artery is overlapped by the fleshy belly of
brachio-radialis.
 In the lower part: the artery becomes superficial lying between the
tendon of flexor carpi radialis (medially) and tendon of brachio-
radialis (laterally).

 

 Summary 221


B. At the wrist:
Radial artery turns backwards around the lateral side of the carpus to
reach the anatomical snuff-box, where it crosses its floor to reach the
dorsum of the hand.

C. In the hand:
1. The radial artery descends on the dorsum of hand, then, passes
forwards through the proximal part of 1st interosseous space between
the two heads of the 1st dorsal interosseous muscle to enter the palm.
2. In the palm of the hand, it emerges between the oblique and transverse
heads of adductor pollicis muscle and runs medially immediately distal
to the bases of the metacarpal bones as deep palmar arch.

N.B. The radial artery is accompanied by two venae comitantes.

- Branches: from above downwards it gives:

A. Radial recurrent artery: arises near the origin of radial artery and
ascends to anastomose with radial collateral, in front of lateral epicondyle.
B. Muscular branches: to supply muscles on the radial side of the forearm.
C. Anterior carpal artery: runs medially across the front of the carpus deep
to the flexor tendons to anastomose with anterior carpal branch of the
ulnar artery together forming the anterior carpal arch.
D. Superficial palmar artery: arises from the radial artery at the wrist
before it turns backwards. It descends through the thenar muscles
(supplying them) and ends by anastomosing with the terminal part of ulnar
artery, completing the superficial palmar arch.
E. Posterior carpal artery: arises from radial artery after turning backwards
reaching the dorsum of the hand. It runs medially across the back of the
carpus deep to the extensor tendons to anastomose with posterior carpal
branch of ulnar artery together forming the posterior carpal arch.
F. Dorsal digital branch: to the lateral border of the thumb.
G. First dorsal metacarpal artery: arises on the dorsum of the hand just
before the radial artery passes between the two heads of first dorsal
interosseous muscle. It divides into two dorsal digital branches to supply
the adjacent sides of the thumb and index fingers.

H & I. Princeps pollicis and Radialis indicis arteries: arise from the
radial artery in the palm of the hand just before passing between the two
heads of the adductor pollicis muscle.
1. Princeps pollicis artery: divides into two palmar digital branches to
supply both sides of the palmar aspect of the thumb.
2. Radialis indicis artery: runs along the palmar aspect of the lateral side of
the index forming its lateral palmar digital branch.

 

 Summary 222


- Surface anatomy: the radial artery is represented by a line extending

between two points:
 Point 1: midway between the epicondyles of the humerus medial to the tendon
of the biceps.
 Point 2: at the front of the lower end of radius where the pulsation of the
artery is felt.

N.B.The distal portion of the artery is indicated by continuing this line around the radial
side of the wrist to the proximal end of the first metacarpal interosseous space.
The deep palmar arch is represented by a curved line long the proximal border of fully
extended thumb.

SUMMARY OF WHOLE COURSE OF ULNAR ARTERY

- Beginning: in the cubital fossa, at the level of neck of radius as the larger of
the two terminal branches of brachial artery.

- Course:
A. In the upper third of forearm: it runs obliquely downwards and
medially to reach the medial side of the front of the forearm.
B. In the lower two thirds of forearm: it descends vertically along the
medial side of the front of the forearm to reach the wrist.
C. At the wrist: it descends superficial to the flexor retinaculum lateral to the
pisiform and medial to the hook of hamate.

- End: it ends in the hand by becoming the superficial palmar arch after giving the
deep palmer branch

- Relations:
A. Posteriorly: from above downwards, the ulnar artery lies on:
1. Brachialis tendon, in the cubital fossa.
2. Flexor digitorum profundus muscle (medial 1/2).
3. Flexor retinaculum, at the wrist.
B. Anteriorly:
1. In the upper third of the forearm, the ulnar artery passes downwards
and medially deep to:
 The two heads of pronator teres.
 Flexor carpi radialis.
 Palmaris longus.
 Flexor digitorum superficialis.
2. In the middle third of the forearm, the ulnar artery (and nerve) is
overlapped by flexor carpi ulnaris muscle.
3. In the lower third of the forearm (above the wrist), the ulnar artery
becomes superficial lying between the tendon of flexor carpi ulnaris
(medially) and tendons of flexor digitorum superficialis (laterally).

 

 Summary 223

C. Medially: the ulnar nerve descends medial to ulnar artery.
1. At the elbow: the artery is separated from the nerve by a gap.
2. In the upper third of the forearm: the ulnar artery runs obliquely
downwards and medially approaching the nerve.
3. In the lower two thirds of the forearm: the nerve lies closely medial to
the ulnar artery.

N.B. The ulnar artery is accompanied by two venae comitantes.

- Branches:
A. Near the elbow:
1. Anterior ulnar recurrent artery: ascends to anastomose with the
anterior branch of inferior ulnar collateral artery in front of the medial
epicondyle of humerus.
2. Posterior ulnar recurrent artery: reaches the back of medial
epicondyle where it anastomoses with superior ulnar collateral artery.
3. Common Interosseous artery: it is a short trunk which, descends
backwards to reach the upper margin of the interosseous membrane,
where it divides into anterior and posterior interosseous arteries.
a) Anterior interosseous artery (the larger branch):
- Course:
* It descends on the anterior surface of interosseous membrane
accompanied by anterior interosseous branch of median nerve
between flexor pollicis longus (laterally) and flexor digitorum
profundus (medially).
* At the upper border of pronator quadratus it pierces the
interosseous membrane to reach back of forearm where it
anastomoses with the termination of posterior interosseous
artery.
* Then it descends accompanied by posterior interosseous nerve
deep to the extensor retinaculum.
* It ends by joining the posterior carpal arch.
- Branches:
* Median artery, which accompanies and supplies median nerve
(vasa nervosa).
* Muscular branches.
* Nutrient arteries of both radius and ulna.
* A descending branch at the upper border of the pronator
quadratus. it descends deep to the muscle to join the anterior
carpal arch.

 

 Summary 224

b) Posterior interosseous artery.
- Course:
* It passes backwards above the interosseous membrane to reach
back of forearm where it descends between the superficial and
deep muscles of the back of forearm accompanied by posterior
interosseous branch of radial nerve.
* In the lower part of the forearm it becomes small and ends by
anastomising with anterior interosseous artery.
- Branches:
* Near its origin, it gives posterior interosseous recurrent artery,
which ascends to anastomose with the posterior descending
branch of profunda brachii on the back of lateral epicondyle.
* Muscular branches to the muscles of the back of forearm.
B. In the forearm: the ulnar artery gives:
Muscular branches: to supply muscles on the medial (ulnar) side of the
forearm.
C. At the wrist: the ulnar artery gives:
1. Anterior carpal artery: crosses the front of the carpus deep to the
flexor tendons to anastomose with anterior carpal branch of radial
artery to form anterior carpal arch.
2. Posterior carpal artery: turns backwards, then runs laterally across
the back of the carpus deep to the extensor tendons to anastomose
with posterior carpal branch of radial artery to form posterior carpal
arch.
D. In the hand (superficial to the flexor retinaculum): the artery ends
by dividing into superficial and deep divisions as follows:
 Deep palmar branch (deep division): arises from the ulnar artery
before it becomes superficial palmar arch. It passes between the
flexor digiti minimi and abductor digiti minimi to anastomose with
radial artery at the base of the 5th metacarpal bone, completing the
deep palmar arch. This branch is accompanied by deep branch of
ulnar nerve.
 Superficial division:: it runs distally just medial to the hook of
hamate and then curves laterally across the palm to form the
superficial palmar arch.
- Surface anatomy: the ulnar artrey is represented by a line passing through three
points:
Point 1: midway between the epicondyles of the humerus medial to the tendon of
biceps.
Point 2: at the medial side of the forearm at the junction of the upper one third with
the lower two thirds.
Point 3: just lateral to the pisiform bone at the wrist.

N.B. The superficial palmar arch is represented by a curved line at the level of the
distal border of the fully extended thumb.

 

 Summary 225

SUMMARY OF THE WHOLE COURSE OF ULNAR NERVE
- Origin: it arises in the axilla from the medial cord of brachial plexus. It arises
mainly from C8 and T1, but fibers from C7 reach the ulnar nerve, either from
the lateral cord in the axilla or from median nerve in the forearm.

- Course and Relations:

 In the axilla: it descends on the medial side of the third part of axillary
artery, lying with the medial cutaneous nerve of forearm between the
artery and the axillary vein.
 In the arm:
- In the upper half of the arm: it descends on the medial side of upper
half of brachial artery, lying with medial cutaneous nerve of forearm
between the artery and the basilic vein.
- At the middle of the arm: opposite the insertion of coraco-brachialis,
it leaves the brachial artery and passes backwards piercing the medial
intermuscular septum (with superior ulnar collateral artery) to reach the
posterior compartment of the arm.
- In the lower half of the arm: it descends in the posterior
compartment of the arm, lying on the medial head of triceps.
 At the elbow: it descends behind the medial epicondyle grooving it
(shallow groove). Then, it enters the forearm by passing between the two
head of flexor carpi ulnaris muscle, accompanied by posterior ulnar
recurrent artery.
 In the forearm: along its whole course in the forearm, it descends on the
medial part of the anterior surface of flexor digitorum profundus. It is
covered by the flexor carpi ulnaris, in the upper 2/3 of the forearm and lies
medial to the ulnar artery in the lower 2/3 of forearm. In the lower 1/3 of
forearm, the nerve becomes superficial lying between the tendon of the
flexor carpi ulnaris (medial to it) and tendons of flexor digitorum
superficialis (lateral to it).
 At the wrist: it descends superficial to the flexor retinaculum, lateral to
the pisiform bone and medial to the ulnar artery.

- End: in front of the flexor retinaculum, it ends by dividing into a superficial branch
(mainly cutaneous) and a deep branch (mainly muscular).
- Branches:
 In the axilla and arm: the nerve gives no branches
 In the forearm: the nerve gives the following branches:
1. Articular branches: to supply the elbow joint.
2. Muscular branches: to supply flexor carpi ulnaris and medial half of
flexor digitorum profundus.
3. Cutaneous branches:
a. Palmar cutaneous branch: supplies the skin of the medial third of
palm

 

 Summary 226

b. Dorsal cutaneous branch: divides into two dorsal digital nerves to
supply the skin of medial third of dorsum of the hand and that of
the medial 1 1/2 fingers.
 Terminal branches: in front of the medial part of the flexor
retinaculum, the ulnar nerve gives superficial and deep terminal
branches.
1. Superficial branch:
 It arises in front of the flexor retinaculum.
 It descends deep to the palmaris brevis muscle, supplying it and then
divides into two palmar digital branches to supply the skin on the
palmar surfaces of the medial 11/2 fingers.
2. Deep branch:
 It arises in front of the flexor retinaculum.
 Then it dips between abductor and flexor digiti minimi in company with
the deep branch of the ulnar artery.
 It then pierces the opponens digiti minimi, curves round the hook of
the hamate and turns laterally across the palm, lying in the concavity
of the deep palmar arch (deep to the flexor tendons) to end near the
lateral border of the palm by breaking up into terminal branches.
 It gives the following branches:
a. Muscular: to muscles of the hypothenar eminence, the medial two
lumbricals, all interosseous muscles, adductor pollicis and
additional supply to the flexor pollicis brevis.
b. Articular: to the wrist and the metacarpo-phalangeal joints.

SUMMARY OF THE WHOLE COURSE OF MEDIAN NERVE

- Origin: it arises in the axilla by two roots from the medial and the lateral cord
of the brachial plexus forming together the median nerve trunk (C5, 6, 7, 8
and T1) on the lateral side of the axilcxlary.

- Course and Relations:

 In the axilla: it descends lateral to the third part of axillary artery.
 In the arm:
- In the upper half of the arm: median nerve descends lateral to the
upper half of brachial artery.
- At the middle of the arm: opposite the insertion of coraco-brachialis, the
median nerve crosses the brachial artery from the lateral to medial side
of the artery, either in front or behind it.
- In the lower half of the arm: it descends medial to the lower half of
brachial artery lying on brachialis.
 At the elbow joint: it lies medial to the brachial artery, in front of
brachialis and behind the bicipital aponeurosis, which separates it from
median cubital vein. It leaves the arm by passing into the cubital fossa of
the forearm.

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 Summary 227
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 In the forearm:
- It enters the cubital fossa medial to the lower part of the brachial
artery and the upper part of ulnar artery where it is crossed
superficially by the bicipital aponeurosis.
- It leaves the cubital fossa by passing between the two heads of
pronator teres separated, posteriorly, by the deep head of the muscle
from the ulnar artery.
- Then, it reaches the deep surface of the flexor digitorum superficialis
where it descends in the middle of the front of the forearm between it
and the lateral half of the flexor gigitorum profundus.
- Immediately above the wrist, it becomes superficial between the
tendon of flexor carpi radialis (lateral to it) and the tendons of flexor
digitorum superficialis (medial to it).
 At the wrist: median nerve enters the palm by passing deep to the flexor
retinaculum.

- End: it ends in the carpal tunnel by dividing into two terminal divisions (lateral
and medial).

- Branches:
 In the axilla and arm: the median nerve gives no branches in the axilla
and the arm.
 In the forearm:

1. Articular branches (in the cubital fossa): supply the elbow and superior
radio-ulnar joint.
2. Muscular branches (in the cubital fossa): supply four muscles (pronator
teres, flexor carpi radialis, palmaris longus and flexor digitorum
superficialis).
3. Anterior interosseous nerve:
- Arises from median nerve as it emerges between the two heads of
pronator teres.
- It descends on the anterior surface of the interosseous membrane
(accompanied by anterior interosseous artery) where it lies between
flexor pollicis longus (lateral to it) and flexor digitorum profundus
(medial to it).
- Then it disappears deep to pronator quadratus and ends by supplying
inferior radio-ulnar and wrist joints.
- It supplies flexor pollicis longus, pronator quadratus and lateral half of
flexor digitorum profundus.

4. Palmar cutaneous branch: arises from median nerve one inch above the
wrist and descends superficial to the flexor retinaculum to supply the
skin of the lateral two thirds of the palm of the hand, except the proximal
small part of thenar skin, which is supplied by lateral cutaneous nerve of
forearm.

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 Summary 228
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 In the hand: it enters the palm deep to the flexor retinaculum (in the carpal
tunnel) where it divides into two terminal divisions:
1. Lateral division (the smaller): it gives the following branches:
a. Recurrent muscular branch: to supply the muscles of thenar
eminence (flexor pollicis brevis, abductor pollicis brevis and opponens
pollicis).
b. Three palmar digital branches: two of them supply the palmar surface
of both sides of the thumb. The third one supplies the palmar surface
of the lateral side of the index and gives a muscular branch to the 1 st
lumbrical muscle.
2. Medial division: divides into two branches:
 The first one gives a muscular branch to the 2nd lumbrical and
then divides into two palmar digital branches to the palmar
surfaces of the adjacent sides of the index and middle fingers.
 The second one divides into two palmar digital branches to
supply the palmar surfaces of the adjacent sides of the middle
and ring fingers.
N.B. The palmar digital branches of median nerve supply not only the whole
palmar aspect but also turn backwards to supply the distal half of the
dorsal aspects of the lateral 3 1/2 fingers.

N.B. The deep branch of the ulnar nerve supplies all intrinsic muscles of the
hand except five muscles (lateral two lumbricals and the three thenar
muscles) which are supplied by the median nerve.

SUMMARY OF THE WHOLE COURSE OF

RADIAL NERVE
- Origin: in the axilla as the larger of the two terminal branches of the posterior
cord of brachial plexus (C5, 6, 7, 8 and T1).

- Course and Relations:

 In the axilla: it descends on the posterior wall of the axilla behind the
third part of the axillary artery.

 In the arm:
- In the upper third: it passes downwards and laterally behind the
proximal part of the brachial artery separating it from the long head of
triceps.
- In the middle third: it leaves the front of the arm by passing backwards
between the long and medial heads of triceps to reach the spiral
groove, where it runs downwards and laterally between lateral and
medial heads of triceps accompanied by profunda brachii vessels.
- In the lower third: it pierces the lateral intermuscular septum
accompanied by the radial collateral artery to reach the front of the arm
again where it descends between brachialis and brachio-radialis down to
the front of the lateral epicondyle.

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 Summary 229
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 In front of the lateral epicondyle: it gives an important deep branch
called posterior interosseous nerve (mainly muscular).Then the radial
nerve itself continues as the superficial radial nerve (mainly cutaneous).

- Branches of radial nerve:

 In the axilla:
1. Muscular: to supply the long and medial heads of triceps.
2. Cutaneous: posterior cutaneous nerve of the arm, which supplies the
skin on the back of the arm from the deltoid tuberosity down to the
elbow.
 In the spiral groove:
1. Muscular: to the lateral and medial heads of triceps and anconeus.
2. Cutaneous:
a. Lower lateral cutaneous nerve of the arm: it supplies the skin on the
lateral surface of the arm from the deltoid tuberosity down to the
elbow.
b. Posterior cutaneous nerve of the forearm: it supplies the skin of the
middle of the back of the forearm down to the wrist.

 In the lower third of the arm (in the groove between brachialis and
brachio-radialis): it gives muscular branches to brachio-radialis and
extensor carpi radialis longus as well as to a small lateral part of the
brachialis muscle.
 Terminal branches in front of the lateral epicondyle: the radial
nerve ends by giving posterior interosseous branch then continues as
superficial radial nerve.

A- Superficial Radial Nerve

- Origin: it begins in front of the lateral epicondyle as the continuation of radial
nerve immediately below the origin of posterior interosseous nerve.
- Course:
 It descends in the lateral part of the front of the forearm overlapped by brachio-
radialis muscle lying on the lateral side of the radial artery as follows:
1. In the upper one third of the forearm, it is separated from the artery by a
triangular gap.
2. In the middle one third of the forearm, it is closely lateral to the artery.
3. In the lower one third of the forearm, it leaves the artery by turning backwards
around lateral surface of radius undercover of the tendon of brachio-radialis.

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 Summary 230

 Short distance above the wrist it appears from undercover of brachio-radialis
tendon, pierces the deep fascia and descends to cross the roof of the anatomical
snuff-box to reach the dorsum of the hand.
- End and branches: it ends in the dorsum of the hand by dividing into five
dorsal digital nerves as follows:
1. Two for both sides of the thumb.
2. One for the lateral border of the index.
3. Two for the two clefts between the index, middle and ring fingers supplying
their adjacent sides.

N.B. These dorsal digital branches supply the skin of lateral two thirds of dorsum of hand
as well as the skin of dorsal aspect of the lateral 3 1/2 fingers as far as their distal
halves only.

B- Posterior Interosseous Nerve

- Origin: it arises from the radial nerve in front of the lateral epicondyle.
- Course: it has the following pathway:
 It descends in front of the elbow under cover of brachio-radialis.
 It first supplies the extensor carpi radialis brevis and supinator, then it pierces
the supinator muscle.
 Within the substance of supinator, it winds around the lateral side of the
upper third of the shaft of radius splitting the muscle into superficial and deep
layers.
 It emerges from the muscle in the back of the forearm, where it descends
(with the posterior interosseous artery) between the superficial and deep
extensors of forearm.
 Then it leaves the posterior interosseous artery by passing under cover of the
extensor pollicis longus to join the anterior interosseous artery directly on the
back of the interosseous membrane.
 Finally, it descends, together with the anterior interosseous artery, deep to the
extensor retinaculum through the 4th compartment to reach back of the wrist.
- End: it ends in expanded termination (pseudoganglion) giving articular filaments.
- Branches:
 Articular: terminal branches to supply inferior radio-ulnar joint, wrist joint and
some inter-carpal joints
 Muscular: to all extensor muscles on the back of the forearm (superficial and
deep) except brachio-radialis, extensor carpi radialis longus and anconeus.


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
 References

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