ANATOMY OF THE HAND
BONES OF HAND
Total of 27 bones in
hand and wrist.
These are grouped
into carpals, metacarp
als, and phalanges.
CARPAL BONES
All carpal bones participate in
wrist function
except for the pisiform.
The scaphoid serves as link
between each row; therefore, it
is vulnerable to fractures.
The distal row of carpal bones
is strongly attached to the base
of the second and third
metacarpals, forming a fixed
unit.
METACARPALS
The hand contains 5 metacarpals.
First Metacarpal articulates proximally with the trapezium.
The other 4 metacarpals articulate with
the trapezoid, capitate and hamate at the base.
The hand contains 14 phalanges.
All 4 distal carpal bones articulate with the
metacarpals at the carpometacarpal (CMC)
joints.
COMPARTMENTS OF THE HAND
11 separate Osteofascial compartments:
•DORSAL
INTEROSSEI (4 COMPARTMENTS)
•PALMAR
INTEROSSEI (4 COMPARTMENTS)
•ADDUCTOR POLLICIS
•THENAR
•HYPOTHENAR
EXTRINSIC MUSCLES OF HAND
EXTRINSIC EXTENSORS
All extensors are extrinsic and supplied by radial nerve.
Except for the interosseous-lumbrical complex.
Group contains:
3 wrist extensors
A larger group of thumb and digit extensors.
The main extensors at wrist are:
•Extensor carpi radialis brevis (ECRB)
•Extensor carpi radialis longus (ECRL)
•Extensor carpi ulnaris (ECU)
EXTRINSIC EXTENSORS
At the digits, extension occurs due to:
•The Extensor digitorum communis
•Extensor indicis proprius
•Extensor digiti minimi
EXTENSOR CARPI RADIALIS BREVIS
The extensors of the wrist are on the Dorsal side of
the forearm
A majority of the wrist extensors begin at the lateral
epicondyle of humerus
:Extensor Carpi Radialis Brevis
Origin: Lateral epicondyle of humerus
Insertion: Base of 3rd metacarpal
Action: Extends and radially deviates the wrist
Innervation: radial nerve (C7 and C8)
EXTENSOR CARPI RADIALIS LONGUS
Origin Lateral
supracondylar ridge of
humerus
Insertion Base of 2nd
metacarpal
Action Extends and radially
deviates at the wrist
Innervation Radial nerve
(C6 and C7)
EXTENSOR CARPI ULNARIS
Origin Lateral epicondyle
of humerus
Insertion Base of 5th
metacarpal
Action Extends and ulnar
deviates hand at wrist
joint
Innervation - Radial nerve
EXTENSOR DIGITORUM
Origin Lateral epicondyle
of humerus
Insertion Extensor
expansions of medial four
digits
Action Extends the four
digits and the wrist
Innervation Posterior
interosseous nerve
EXTENSOR DIGITI MINIMI
Origin Lateral epicondyle of
humerus
Insertion 5th digit
Action Extends 5th digit at
metacarpophalangeal and
interphalangeal joints
Innervation Posterior
interosseous nerve
EXTENSOR INDICIS
Origin: Posterior sufrace of
ulna and interosseous
membrane
Insertion: Extensor
expansion of 2nd digit
Action: Extends 2nd digit
and helps to extend hand
Innervation : Posterior
interosseous nerve
EXTRINSIC EXTENSORS
Extension at the thumb
is brought about by:
•The Abductor pollicis
longus
•Extensor pollicis
brevis
•Extensor pollicis
longus
EXTENSOR POLLICIS BREVIS
Origin : Posterior surface of
radius and interosseous
membrane
Insertion : Base of proximal
phalanx of thumb
Action : Extends proximal
phalanx of thumb at
carpometacarpal joint
Innervation: Posterior
interosseous nerve
EXTENSOR POLLICIS LONGUS
Origin : Posterior surface of
middle 1/3 of ulna
Insertion : Base of distal
phalanx of thumb
Action: Extends distal
phalanx of thumb at
carpometacarpal and
interphalangeal joints
Innervation: Posterior
interosseous nerve
ABDUCTOR POLLICIS LONGUS
Origin Posterior
surfaces of ulna,
Insertion Base of 1st
metacarpal
Action Abducts thumb
Innervation the radial
nerve
EXTRINSIC FLEXORS
The muscles that flex
the wrist are on the
palmer side.
A group of them begin
at the medial
epicondyle of the
humerus at the elbow
EXTRINSIC FLEXORS
3 wrist flexors
A larger group of thumb and digit flexors
Are innervated by the median nerve
Except for the FCU, and the FDP to the
small and ring finger, which are
innervated by the ulnar nerve.
EXTRINSIC FLEXORS
The main Flexors at the wrist joint are:
•The Flexor carpi radialis
•The Flexor carpi ulnaris
•The Palmaris longus
PALMARIS LONGUS
Origin Medial epicondyle
of humerus
Insertion Distal half of
flexor retinaculum and
palmar aponeurosis
Action Flexes hand at the
wrist
Innervation Median nerve
(C7 and C8)
FLEXOR CARPI RADIALIS
Origin Medial epicondyle
of humerus
Insertion Base of 2nd
metacarpal
Action Flexes and radial
deviates the hand (at wrist)
Innervation Median nerve
(C6 and C7)
FLEXOR CARPI ULNARIS
Origin medial
epicondyle of
humerus
Insertion Pisiform
bone, hook of hamate
bone, and 5th
metacarpal bone
Action Flexes and
ulnar deviates hand
(at wrist)
Innervation Ulnar
nerve (C7 and C8)
FLEXOR DIGITORUM SUPERFICIALIS
Origin medial epicondyle
of humerus
Insertion middle
phalanges of digits 2 - 5
Action Flexes middle
phalanges at proximal
inter phalangeal joints
also flexes proximal
phalanges at metacarpo
phalangeal joints and
hand
Innervation Median nerve
(C7, C8 and T1)
FLEXOR DIGITORUM PROFUNDUS
Origin Proximal 3/4 of
ulna
Insertion Base of the
distal phalanx of digits 2
–5
Action Flexes distal
phalanges at distal
interphalangeal joints
Innervation
Medial part: ulnar nerve
Lateral part: median
nerve
FLEXOR POLLICIS LONGUS
Origin Anterior surface of
radius and adjacent
interosseous membrane
Insertion Base of distal
phalanx of thumb
Action Flexes phalanges
of 1st digit (thumb)
Innervation Anterior
interosseous nerve from
median nerve (C8 and T1)
PRONATOR QUADRATES
Origin Distal 1/4
of anterior
surface of ulna
Insertion Distal
1/4 of anterior
surface of radius
Action Pronates
forearm;
Innervation
median nerve
PRONATOR TERES
Origin Medial
epicondyle of
humerus
Insertion Middle of
lateral surface of
radius
Action Pronates
Innervation Median
nerve (C6 and C7)
INTRINSIC MUSCLES OF HAND
Situated totally within the hand
Divided into 4 groups:-
•Thenar
•Hypothenar
•Lumbricals
•Interossei muscles
THE THENAR GROUP
The Thenar group
consists of:
•The Abductor
pollicis brevis
•Flexor pollicis
brevis
•Opponens pollicis
•Adductor pollicis
muscles
ABDUCTOR POLLICIS BREVIS
Origin Scaphoid and
Trapezium
Insertion Lateral side of
base of proximal phalanx
of thumb
Action Abducts thumb
Innervation median nerve
(C8 and T1)
FLEXOR POLLICIS BREVIS
Origin Flexor retinaculum
and tubercles of scaphoid
and trapezium
Insertion Lateral side of
base of proximal phalanx of
thumb
Action Flexes thumb
Innervation Recurrent
branch of median nerve (C8
and T1)
OPPONENS POLLICIS
Origin Flexor retinaculum and
tubercles of scaphoid and
trapezium
Insertion Lateral side of 1st
metacarpal
Action Draws 1st metacarpal
laterally to oppose thumb
toward center of palm
Innervation Recurrent branch
of median nerve (C8 and T1)
ADDUCTOR POLLICIS
It has 2 heads that are separated by a
gap through which the radial artery
passes
Origin: Oblique head – bases of 2nd
and 3rd metacarpals, capitate and
adjacent carpal bones
Transverse head – anterior
surface of body of 3rd metacarpal
bone
Insertion: medial side of base of
proximal phalanx of thumb
Innervation: ulnar nerve
Action: adducts thumb towards
middle digit
THE HYPOTHENAR GROUP
Hypothenar
muscles
1. Opponens Digiti
Minimi
2.Abductor Digiti
Minimi
3.Flexor Digiti
Minimi Brevis
4.Palmaris Brevis
OPPONENS DIGITI MINIMI
Origin Hook of hamate
and flexor retinaculum
Insertion Medial border
of 5th metacarpal
Action Brings little finger
(5th digit) into opposition
with thumb
Innervation Deep branch
of ulnar nerve (C8 and
T1)
ABDUCTOR DIGITI MINIMI
The most superficial of the
hypothenar muscles
forming the hypothenar
eminence
Origin: Pisiform bone
Insertion: Medial side of
base of proximal phalanx
of 5th digit
Action: Abducts 5th digit
FLEXOR DIGITI MINIMI BREVIS
Origin Hook of hamate
and flexor retinaculum
Insertion Medial side of
base of proximal phalanx
of little finger
Action Flexes proximal
phalanx of little (5th)
finger
Innervation ulnar nerve
PALMAR BREVIS
It lies in the fascia deep to the
skin of the hypo thenar
eminence
A relatively unimportant muscle
except that it covers and
protects the ulnar nerve and
artery
Origin: Flexor retinaculum and
palmar aponeurosis
Insertion: Skin on the medial side
of the palm
Action: Wrinkles the skin on the
medial side of the palm and
deepens the hollow of the palm, as
in cupping of the hand, thereby
aiding the grip
INTEROSSEI MUSCLES
Interosseous Muscles
They are located between the
metacarpal bones
Arranged in 2 layers: 4 Palmar and 4
Dorsal
Located between bones
1. Dorsal interossei 1 to 4
Origin: Adjacent sides of 2
metacarpal bones
Insertion: Extensor expansion's and
bases of proximal phalanges of digit
2 to 4
Action: Abducts digits and assist
lumbricals
2. Palmar interossei 1 to 4
Origin: Palmar surfaces of 2nd, 3th ,
4th and 5th metacarpal bones
Insertion: Extensor expansion of
digits and bases of proximal
phalanges of digits 2, 4, and 5
Action: Adducts digits and assist
lumbricals
LUMBRICAL MUSCLES
They are named as such because
of their elongated wormlike form
1. Lumbricals 1 and 2
Origin: lateral 2 tendons of flexor
digitorum profundus
2. Lumbricals 3 and 4
Origin: medial 3 tendons of flexor
digitorum profundus
Insertion: lateral sides of
extensor expansions of digits 2
to 5
Action: To flex digits at MCP
joints and extend IP joints
THE PULLEY SYSTEM
The pulley system is critical to flexion of the finger.
The retinacular system for each of the fingers contains 5 annular
pulleys and 4 cruciform pulleys.
The thumb has 2 annular pulleys and 1 oblique pulley.
The system supplies mechanical advantage by maintaining the flexor
tendons close to the joint's axis of motion.
In doing so, the pulleys prevent bowstringing.
.
THE PULLEY
PULLEY SYSTEMOF
SYSTEM OF THE
THE THUMB
THUMB
ARTERIES
Radial and ulnar arteries and their branches provide all the blood
to the hand
A. Radial Artery
Smaller of the 2 terminal branches of the brachial artery
1. superficial palmar branch superficial palmar arterial
arch
2. princeps pollicis artery – supplies the thumb
3. radialis indicis – supplies lateral side of digit 2
4. deep palmar arterial arch – formed mainly by the radial
artery which joins the deep branch of the ulnar artery
palmar metacarpal arteries – arise from the deep palmar arch, run
distally and join the common palmar digital arteries which arise
from the superficial palmar arterial arch
DORSAL ARTERY OF HAND
Dorsal carpal branch of ulna and
radius
Dorsal carpal arch
Dorsal metacarpal artery
Dorsal digital
artery
Middle & distal phalanges
Palmar proper digital arteries
ARTERIES
B. Ulnar Artery
Enters the palm on the lateral side of the ulnar nerve superficial to
the flexor retinaculum
- passes lateral to the pisiform bone
1. deep palmar branch deep palmar arterial arch, passes deep
through the hypothenar muscles and anastomoses with the radial
artery
2. superficial palmar arterial arch
- formed mainly by the ulnar artery
- located distal to the deep palmar arch
- gives rise to the three common digital arteries that
anastomoses with the palmar metacarpal arteries from the deep
palmar arch
each common digital artery divides into a pair of proper palmar
digital arteries which run along the sides of the 2nd to 4th digits
VEINS
Veins generally follow the
deep arterial system as
venae comitantes.
A superficial venous
system also exists at the
dorsum of the hand and
contributes to the
cephalic and basilic veins
in the upper extremity.
ULNAR NERVE
1. Ulnar (C(7)8-T1): through Guyon's canal, past hook
of hamate
Sensory: Medial palm & 1 1/2 digits via: palmar,
palmar digital branches
Medial dorsal hand & 1 1/2 digits via:
dorsal, dorsal digital, & proper digital
branches
Nerve divides at hypothenar eminence
Motor: Superficial Branch @[lateral to pisiform]
Palmaris brevis
Deep (Motor) Branch [around hook of
hamate]
Adductor pollicis
THENAR MUSCLES
Flexor pollicis brevis [FPB] [with median]
HYPOTHENAR MUSCLES
Abductor digiti minimi [ADM]
Flexor digiti minimi brevis[FDMB]
Opponens digiti minimi [ODM]
INTRINSIC MUSCLES
Dorsal interossei [DIO] [abduct DAB]
Volar interossei [VIO] [adduct PAD]
Lumbricals [medial two (3,4)]
MEDIAN NERVE
Median (C(5)6-T1) : runs through carpal tunnel, then
cutaneous branches off at (risk in Carpal Tunnel release)
Sensory: Palmar Cutaneous Branch
Dorsal distal phalanges of 3 1/2 digits: via
proper palmar digital branches
Volar wrist capsule
Volar 3 1/2 digits and lateral palm: via palmar
& palmar digital branches (multiple variations
of thumb sensory innervation)
Motor: Motor Recurrent (Thenar motor) Branch:
Usually branches off median before carpal
tunnel
THENAR
Abductor pollicis brevis [APB]
Opponens pollicis
Flexor pollicis brevis [FPB]
<l>(Joint innervation with ulnar nerve)</l>
INTRINSIC
Lumbricals [lateral two (1,2)]
RADIAL NERVE
Radial (C5-T1):
Sensory: Dorsal 3 1/2 digits and
hand: via superficial
branch (dorsal digit
branches)
Dorsal wrist capsule
otor: NONE (in hand)
FLEXOR ZONE OF HAND
ZONE BOUNDARIES COMMENT
I FDS insertion to Injuries amenable to repair (e.g.
distal tip Jersey finger)
II Midpalm Called “No man's land” because
fibroosseous tunnel high rate of complications.
to FDS insertion
III Transverse Carpal Injuries often associated with
ligament to fibro- Median nerve or arterial arch
osseous tunnel injuries. Explore and repair all.
IV Transverse carpal Uncommon site of injury. Repair
ligament (carpal usually requires carpal tunnel
tunnel) release and repair. Median nerve at
risk.
V Proximal to the TCL Injuries require end-to-end repair
Thumb I Thumb IP to distal Similar to finger
tip
Thumb II Thumb CMC to IP Similar to finger
Thumb III Thenar eminence Repair may require lengthening or
graft procedure
THANK YOU
