Arm and elbow

Musculoskeletal Block - Lecture 7

Objective:
✓ Describe the attachments, actions and innervations of:
a. Biceps brachii
b. Coracobrachialis c. Brachialis
d. Triceps brachii
✓ Define the boundaries of the cubital fossa and enumerate its contents.
✓ Demonstrate the following features of the elbow joint:
a. Articulating bones
b. Capsule
c. Lateral & medial collateral ligaments
d. Synovial membrane
✓ Demonstrate the movements; flexion and extension of the elbow.
✓ List the main muscles producing the above movements.
✓ Define the boundaries of the cubital fossa and enumerate its contents.

Color index:
Important
In male’s slides only
In female’s slides only
Extra information, explanation

Editing file
Contact us:
Anatomy439@gmail.com
The Arm
An aponeurotic sheet separating various muscles of the upper limbs, including lateral
and medial humeral septa.
The lateral and medial intermuscular septa divide the distal part of the arm into two
compartment : Anterior ( flexor compartment ), Posterior ( extensor compartment )

1- Anterior Fascial Compartment

1- muscle:
- Biceps Brachii
2- nerves: - Coracobrachialis
- Musculocutaneous - Brachialis
- Median
- Radial
- Ulnar 3- Blood vessels :
- Brachial artery
- Basilic vein

Muscles Of Anterior Compartment

Muscle Biceps Brachii Coracobrachialis Brachialis
Origin -Long Head (lateral head): from Tip of the coracoid Front of the lower half
supraglenoid tubercle of scapula process of scapula ( of humerus
(intracapsular). with short head of
-short Head: from the tip of coracoid biceps brachii )
process of scapula.
-The two heads join in the middle of the
arm brachii)

Insertion -Into the posterior part of the radial Middle of the medial Anterior surface of
tuberosity. side of the shaft of coronoid process of
-Into the deep fascia of the medial the humerus ulna
aspect of the forearm through bicipital
aponeurosis

Nerve Musculocutaneous -musculocutaneous (

supply medial part )
-Radial (lateral part )

Action -Strong supinator of the forearm -flexor Strong flexor of the

- powerful Flexor of elbow ( the main -weak adductor of the forearm
elbow flexor) arm
-Weak flexor of shoulder
-used in screwing

Picture
2- Posterior Fascial Compartment:

1- muscle:
- triceps brachii.
2- nerves:
-ulnar nerve.
-radial nerve. 3- Blood vessels :
- Profunda brachial
Ulnar collateral arteries.

cross sectional of arm

Muscles Of posterior Compartment

Muscle Triceps Brachii
● Long head: from infraglenoid tubercle of the scapula.(1) (remember
the origin of the long head of the biceps head is supraglenoid tubercle).

● lateral head: from the upper half of the posterior surface of the shaft
Origin of the humerus above the spiral groove. (2)

● Medial head: from the lower half of the posterior surface of the shaft
of the humerus below the spiral groove. (3)

Insertion Common tendon inserted into the upper surface of the olecranon process
of ulna.

Nerve
Radial nerve.
supply

Action Strong extensor of elbow joint.

Picture (2) (3)

(1)
Cubital fossa:
- is a an area of transition between the anatomical arm and the forearm, located as
triangular depression on the anterior surface of the elbow joint.
- It is a triangular depression that lies in front of the elbow.

● Base: Line drawn through the two epicondyles of humerus.

●Laterally: Brachioradialis.

● Medially: Pronator teres.

Boundaries
● Roof: Skin, superficial & deep fascia and bicipital
aponeurosis.

● Floor: Brachialis Medially and supinator Laterally.

Content 1. Median nerve.

(From the 2. Brachial artery divides into radial & ulnar arteries.
medial to the 3. Biceps brachii tendon.
lateral) 4. Deep branch of radial nerve.

Clinical relevance: Only in boys slide

● The brachial pulse can be felt by palpating immediate medial to the

biceps tendon in the cubital fossa.

● The median cubital vein is located superficially within the roof of the
cubital fossa.

● It connects the basilic and cephalic veins. And ce be accessed easily-this

makes it a common site for venipuncture.
 Elbow joint:
It is the joint connecting the upper arm with the forearm, and is classified as a Uniaxial
Synovial Hinge Joint

Consists of two separate Articulations:

● Above: Trochlea and the capitulum of the humerus.

● Below: Trochlear notch of the ulna and the head of the radius.

As all bone articulations, The articular surfaces of the elbow joint

are covered with articular (hyaline) cartilage

Capsule :
Capsule Above Below

To the humerus along the upper margins To the margin of the coronoid process
Anteriorly
of the coronoid and radial fossa and to the of the ulna and to the annular
front of the medial and lateral ligament, which surrounds the head
Attached:
epicondyles (1) of the radius. (2)

Posteriorly To the margins of the olecranon fossa of To the upper margin and sides of the
the humerus (3) olecranon process of the ulna and to
attached: the annular ligament. (3)

● The elbow joint has a capsule enclosing the joint. This in itself is strong and fibrous,
strengthening the joint.
● The joint capsule is thickened medially and laterally to form collateral ligaments, which
stabilize the flexing and extending motion of the arm.

(1) (2) (3)

annular ligament, which

surrounds the head of the radius.

Synovial membrane :
-This lines the inner surface of the capsule and covers
fatty pads in the floors of the coronoid, radial, and
olecranon fossa.

-Is continuous below with synovial membrane of the

superior radioulnar joint (Contains the synovial fluid)
 ligaments of the elbow

1- Lateral ligament ( radial collateral ligament)

shape apex base

attached to the Lateral attached to the upper

Triangular epicondyle of humerus. part of the annular
ligament.

2- Medial ligament ( ulnar collateral ligament)

Anterior Posterior Transverse band

strong cord-like band weaker fan-like band

Between Medial
Between Medial Passes between the
epicondyle and the
epicondyle and the anterior and posterior
olecranon process of
coronoid process of ulna. bands.
ulna.

BURSAE
● bursa is a membranous sac filled with
synovial fluid.
● It acts as a cushion to reduce friction
between the moving parts of a joint, limiting
degenerative damage.

Bursae around the elbow joint:

● Intratendinous – located within the tendon of the triceps brachii.
● Subtendinous – between the olecranon and the tendon of the triceps
brachii, reducing friction between the two structures during extension
and flexion of the arm.
● Subcutaneous (olecranon) bursa – between the olecranon and the
overlying connective tissue (implicated in olecranon bursitis).

Elbow joint articulations

- Strong medial and lateral ligaments.
- Wrench-shaped articular surface of the olecranon
and the pulley-shaped trochlea of humerus
- These help to stabilize the elbow joint
Relation
Anterior Posterior Medial Lateral

-Brachialis - Small bursa Ulnar nerve -Common

-Tendon of intervening extensor
biceps “ Considered tendon
-Median nerve -Triceps the largest (attached to
-Brachial muscle unprotected Lateral
artery nerve by epicondyle of
muscle or the humerus)
bone”.
-Supinator

Movement
Extension Flexion

Is limited by the tension of the limited by the anterior surfaces

anterior ligament ( medially) of the forearm and arm coming
and the brachialis muscle. into contact.

The joint is supplied by branches from the (nerves and arteries):

- median nerve
- ulnar nerve (posteriorly)
- radius nerve (anteriorly)
- musculocutaneous nerve
- recurrent and collateral
branches from the deep brachial
arteries (profunda brachii)
Carrying Angle
Angle Opens About
1 2 3
Between the long Laterally . ● 170 degrees in
axis of the extended male
forearm and the ● 167 degrees in
long axis of the arm. female

Disappears Permits
5
4 The forearms to clear the
When the elbow
joint is flexed. hips in swinging
movements during
walking, and is important
when carrying objects.
Clinical correlations
Wrench-shaped Strong medial
articular surface of the
olecranon and the The elbow joint is and lateral
pulley-shaped trochlea stable because of ligaments.
of humerus the:

BURSITIS

1 1- Subcutaneous bursitis:
*Repeated friction and pressure on the bursa can cause it to become inflamed.
*Because this bursa lies relatively superficially, it can also become infected (e.g cut
from a fall on the elbow)
2- Subtendinous bursitis
*This is caused by repeated flexion and extension of the forearm, commonly seen in
assembly line workers.
*Usually flexion is more painful as more pressure is put on the bursa.

Avulsion of the epiphysis of the medial epicondyle

- is also common in childhood because the medial ligament is much

2
stronger than the bond of union between the epiphysis and the diaphysis.
- They are usually a result from an avulsion (pull off) injury caused by :
a valgus stress at the elbow and contraction of the flexor muscles as in :
1. fall on an outstretched hand with the elbow in full extension
2. posterior elbow dislocation 3. direct blow

Dislocation

3
● -Elbow dislocations are common & most are posterior.
● -Posterior dislocation usually follows falling on the outstretched hand with
the elbow flexed
● -Posterior dislocations of the joint are common in children because the
parts of the bones that stabilize the joint are incompletely developed
● The distal end of the humerus is driven through the weakest part of the joint
capsule, which is the anterior side.
● -The ulnar collateral ligament is usually torn and there can also be ulnar
nerve involvement
● -Most elbow dislocations are posterior, and it is important to note that elbow
dislocations are named by the position of the ulna and radius, not the
humerus.
*The radius/ulna is dislocated posteriorly NOT the humerus *
valgus : a deformity involving oblique displacement of part of a limb away from the midline.
Summary med435
MCQs
Q1: which of the following Q2: what is the muscle Q3:brachialis origin is in
is not a part of the flexor that is responsible in front of the …… half of
compartment? “screwing”? humerus?
A.Biceps A.coracobrachialis A.meddle
B.median nerve B.biceps brachii B.lower
C.brachial artery C.brachialis C.upper
D.triceps D.triceps

Q4:what is the origin of Q5:Nerve that supply the Q6:the vessel in posterior
coracobrachialis?
A.supraglenoid tubercle of scapula triceps muscle? fascial?
B.tip of the coracoid process of scapula A.radial nerve A.profunda brachii.
C.anterior surface of coracoid process of
ulna
B.ulnar nerve B.Basilic vein.
D.middle of the medial side of the shaft C.median nerve C.genicular artery.
of the humerus
D.axillary nerve D.fibular artery .

Q7:what’s shape of cubital Q8:what’s the action of triceps Q9: identify the muscle
fossa? muscle? above?
A.circular. A.extensor of shoulder joint.
B.triangular. B.flexion of elbow joint. A. Biceps brachii
C.square. C.extensor of elbow joint. B. Brachioradialis
D.flexion of shoulder joint. C. Coracobrachialis
D.cubic.
D. Triceps

Q10: which of the following Q11:subcutaneous bursitis is caused Q12:which one of the following
doesn’t supply the elbow joint? by? arteries supply the elbow joint?

A.Repeated friction and pressure A.highest thoracic artery

A. median nerve
B.avulsion (pull off) injury B.axillary artery
B. ulnar nerve
C.repeated flexion and extension C.superior ulnar collateral artery
C. radius nerve
D.bone fractures D.brachiocephalic artery
D. Axillary nerve

Q6)A Q12)C
Q5)A Q11)A
Q4)B Q10)D
Q3)B Q9)C
Q2)B Q8)C
Q1)D Q7)B
 SAQs
Q1: What is the content of cubital fossa?
A: 1. Median nerve.
2. Brachial artery divides into radial & ulnar arteries.
3. Biceps brachii tendon.
4. Deep branch of radial nerve.

Q2: What’s the Posterior Fascial Compartment?

A: 1- muscle:triceps brachii
2- vessels:profunda brachii artery./ulnar collateral arteries.
3-nerves:ulnar nerve./radial nerve.

Q3: Compare between Flexion and Extension?

A: Slide6 :
Extension: Is limited by the tension of the anterior ligament ( medially) and the brachialis muscle.
Flexion : limited by the anterior surfaces of the forearm and arm coming into contact.

Q4: What is the nerve supply of biceps brachii and coracobrachialis?

A: slide3 : Musculocutaneous

Q5: Identify the muscle? supplied by ?

A: brachialis
-musculocutaneous ( medial part )
-Radial (lateral part )

This lecture is done by:

Omar bassam
Ghaida alassiry
Yara alasmari

Special thanks to Manal Altwaim

Team leaders:
Mayasem Alhazmi
Fahad Alajmi
SPECIAL THANKS TO THE AMAZING
#MED438 ANATOMY TEAM