The region of the wrist pdf - Upper limb

394

CHAPTER 9

Palmar cutaneous branch of the median nerve

aponeurosis

insertion into the flexor retinaculum and the palmar

(if present), passing to its

Palmaris longus tendon

Palmar cutaneous branch of the ulnar nerve

lies lateral to the ulnar nerve.

Ulnar artery

lies lateral to the pisiform bone.

Ulnar nerve

inaculum but is included for the sake of completeness.)

bone. (This tendon does not actually cross the flexor ret

ending on the pisiform

Flexor carpi ulnaris tendon,

naculum from medial to lateral (Fig. 9.54):

The following structures pass superficial to the flexor reti

Wrist

structures as possible.

time, examine your own wrist and identify as many of the

identify the structures from medial to lateral. At the same

In a transverse section through the wrist (Fig. 9.54),

for injury.

joint. From a clinical standpoint, the wrist is a common site

the tendons, arteries, and nerves in the region of the wrist

a student have a sound knowledge of the arrangement of

Before learning the anatomy of the hand, it is essential that

The Region of the Wrist

to the wrist and carpal joints

Articular branches

pollicis longus, and the extensor indicis

pollicis longus, the extensor pollicis brevis, the extensor

digiti minimi, the extensor carpi ulnaris, the abductor

and the supinator, the extensor digitorum, the extensor

to the extensor carpi radialis brevis

Muscular branches

Branches

face of the wrist joint.

muscles (Fig. 9.65). It eventually reaches the posterior sur

in the interval between the superficial and deep groups of

posterior compartment of the forearm. The nerve descends

of the radius in the substance of the muscle to reach the

supinator and winds around the lateral aspect of the neck

the humerus in the cubital fossa (Fig. 9.61). It pierces the

from the radial nerve in front of the lateral epicondyle of

The deep branch arises

Deep Branch of the Radial Nerve

Forearm

Nerve of the Posterior Fascial Compartment of the

The Upper Limb

■

Structures on the Anterior Aspect of the

■

FIGURE 9.63

Insertions of long flexor and extensor tendons in the fingers. Insertions of the lumbrical and interossei muscles

pophalangeal joints and extending the interphalangeal joints.

are also shown. The uppermost figure illustrates the action of the lumbrical and interossei muscles in flexing the metacar-

extensor digitorum

interossei and lumbrical muscles

axis of rotation

flexor digitorum profundus

flexor digitorum superficialis

vincula brevia

vincula longa

dorsal extensor expansion

lumbrical

extensor
digitorum

interosseous

third metacarpal

extensor digitorum

third metacarpal

interosseous

flexor digitorum profundus

flexor digitorum superficialis

lumbrical

Basic Anatomy

synovial sheath.

the flexor retinaculum. The tendon is surrounded by a

going through a split in

Flexor carpi radialis tendon

surrounded by a synovial

Flexor pollicis longus tendon

Median nerve

both groups of tendons share a common synovial sheath.

to these, the tendons of the flexor digitorum profundus;

and, posterior

Flexor digitorum superficialis tendons

lum from medial to lateral (Fig. 9.54):

The following structures pass beneath the flexor retinacu

395

■

sheath

■

triceps

ulnar nerve

medial epicondyle
olecranon process

flexor carpi ulnaris

posterior subcutaneous

border of ulna

supinator

flexor digitorum profundus

flexor carpi ulnaris

posterior cutaneous branch

of ulnar nerve

extensor carpi ulnaris

extensor digiti minimi

extensor digitorum

extensor indicis

extensor pollicis longus

extensor pollicis brevis

abductor pollicis longus

extensor retinaculum

extensor digitorum

extensor digiti minimi

extensor carpi ulnaris

posterior interosseous artery

deep branch of radial nerve

extensor carpi ulnaris

extensor digiti minimi

extensor digitorum

anconeus

extensor carpi radialis brevis

extensor carpi radialis longus

lateral epicondyle

brachioradialis

FIGURE 9.64

Posterior view of the forearm. Parts of the extensor digitorum, extensor digiti minimi, and extensor carpi ulnaris

have been removed to show the deep branch of the radial nerve and the posterior interosseous artery.

396

CHAPTER 9

lateral part of the posterior surface of the radius.

share a common synovial sheath and are situated on the

extensor indicis tendons

Extensor digitorum

the distal radioulnar joint.

is situated posterior to

Extensor digiti minimi tendon

terior aspect of the head of the ulna

which grooves the pos

Extensor carpi ulnaris tendon,

ulum from medial to lateral (Fig. 9.54):

The following structures pass beneath the extensor retinac

Superficial branch of the radial nerve

Cephalic vein

Basilic vein

nerve

Dorsal (posterior) cutaneous branch of the ulnar

retinaculum from medial to lateral (Fig. 9.54):

The following structures pass superficial to the extensor

Wrist

The Upper Limb

Structures on the Posterior Aspect of the

■

and

medial epicondyle

flexor digitorum profundus

anterior interosseous artery

piercing interosseous membrane

extensor pollicis longus

extensor indicis

posterior metacarpal arteries

first dorsal interosseous

radial artery

extensor carpi radialis brevis

extensor carpi radialis longus

extensor pollicis brevis

abductor pollicis longus

brachioradialis

extensor carpi radialis longus

extensor carpi radialis brevis

deep branch of radial nerve and

posterior interosseous artery

interosseous recurrent artery

supinator

extensor digitorum

extensor digiti minimi

extensor carpi ulnaris

anconeus

FIGURE 9.65

Posterior view of the forearm. The superficial muscles have been removed to display the deep structures.

Basic Anatomy

which crosses in front of the

branch of the median nerve,

palmar cutaneous

9.38 and 9.55) is derived from the

supply to the skin of the palm (Figs.

sensory nerve

The

so improve the grip of the palm in holding a rounded object.

rugate the skin at the base of the hypothenar eminence and

superficial branch of the ulnar nerve. Its function is to cor

and is inserted into the skin of the palm. It is supplied by the

arises from the flexor retinaculum and palmar aponeurosis

(Fig. 9.55) is a small muscle that

palmaris brevis

The

the site of joints. Sweat glands are present in large numbers.

sites of skin movement, which are not necessarily placed at

fibrous bands. The skin shows many flexure creases at the

bound down to the underlying deep fascia by numerous

The skin of the palm of the hand is thick and hairless. It is

pollicis brevis (Fig. 9.65).

the tendons of the abductor pollicis longus and extensor

between the lateral collateral ligament of the wrist joint and

The radial artery reaches the back of the hand by passing

extends above and below the retinaculum.

compartment is provided with a synovial sheath, which

that contain the tendons of the extensor muscles. Each

underlying radius and ulna and form six compartments

Beneath the extensor retinaculum, fibrous septa pass to the

common compartment.

have separate synovial sheaths but share a

vis tendons

extensor pollicis bre

Abductor pollicis longus

lateral part of the posterior surface of the radius.

share a common synovial sheath and are situated on the

brevis tendons

Extensor carpi radialis longus

medial side of the dorsal tubercle of the radius.

winds around the

Extensor pollicis longus tendon

397

■

and

■

and the

The Palm of the Hand

Skin

Muscles of the Posterior Fascial Compartment of the Forearm

T A B L E 9 . 8

Muscle

Origin

Insertion

Nerve Supply

Nerve Roots

Action

Extensor carpi

radialis brevis

Lateral epicondyle of

humerus

Posterior surface

of base of third

metacarpal bone

Deep branch of

radial nerve

C7, 8

Extends and abducts

hand at wrist joint

Extensor

digitorum

Lateral epicondyle of

humerus

Middle and distal

phalanges of

medial four

fingers

Deep branch of

radial nerve

C7, 8

Extends fingers and hand

(see text for details)

Extensor digiti

minimi

Lateral epicondyle of

humerus

Extensor expansion

of little finger

Deep branch of

radial nerve

C7, 8

Extends metacarpal

phalangeal joint of little

finger

Extensor carpi

ulnaris

Lateral epicondyle of

humerus

Base of 5th

metacarpal bone

Deep branch of

radial nerve

C7, 8

Extends and adducts

hand at wrist joint

Anconeus

Lateral epicondyle of

humerus

Lateral surface

of olecranon

process of ulna

Radial nerve

C7, 8; T1

Extends elbow joint

Supinator

Lateral epicondyle of

humerus, anular

ligament of proximal

radioulnar joint, and

ulna

Neck and shaft of

radius

Deep branch of

radial nerve

C5, 6

Supination of forearm

Abductor pollicis

longus

Posterior surface of

shafts of radius and

ulna

Base of first

metacarpal bone

Deep branch of

radial nerve

C7, 8

Abducts and extends

thumb

Extensor pollicis

brevis

Posterior surface of

shaft of radius

Base of proximal

phalanx of thumb

Deep branch of

radial nerve

C7, 8

Extends

metacarpophalangeal

joints of thumb

Extensor pollicis

longus

Posterior surface of

shaft of ulna

Base of distal

phalanx of thumb

Deep branch of

radial nerve

C7, 8

Extends distal phalanx of

thumb

Extensor indicis

Posterior surface of

shaft of ulna

Extensor expansion

of index finger

Deep branch of

radial nerve

C7, 8

Extends

metacarpophalangeal

joint of index finger

The predominant nerve root supply is indicated by boldface type.