Human Anatomy Vol 1

UPPEB LIMB

For three

muscles

of thenar

eminence

Digital nerves

with branches

to 1st and 2nd

lumbricals

Fig. 9.12: Distribution of median nerue

Relolions

L In the cubital fossa, median nerve lies medial to the

brachial artery, behind the bicipital aponeurosis, and

in front of the brachialis (see Fi9.8.1.6).

2 The median nerve enters the forearm by passing

between the two heads of the pronator teres. Here it

crosses the ulnar artery from which it is separated

by the deep head of the pronator teres (Fig. 9.11).

3 Along with the ulnar artery, the median nerve passes

beneath the fibrous arch of the flexor digitorum

superficialis, and runs deep to this muscle on the

surface of the flexor digitorum profundus. It is

accompanied by the median attety, a branch of the

anterior interosseous artery. About^5 cm above the

flexor retinaculum (wrist), it becomes superficial and

lies between the tendons of the flexor carpi radialis

(laterally) and the flexor digitorum superficialis

(medially). It is overlapped by the tendon of the

palmaris longus (Fig. 9.6).

4 The median nerve enters the palm by passing deep

to the flexor retinaculum through the carpal tunnel.

Bronches

7 Muscular branches are given off in the cubital fossa to

flexor carpi radialis, palmaris longus and flexor

digitorum superficialis (Fig. 9.12).

2 The anterior interosseous branch is given off in the

upper part of the forearm. It supplies the flexor

pollicis longus, the lateral half of the flexor digitorum

profundus (giving rise to tendons for the index and

middle fingers) and the pronator quadratus. The

nerve also supplies the distal radioulnar and wrist

joints (Fig.9.12).

3 The palmar cutaneous branch arises a short distance

above the flexor retinaculum,lies superficial to it and

supplies the skin over the thenar eminence and the

central part of the palm.

4 Articular branches are given to the elbow joint and to

the proximal radioul:rar joint.

5 Vascular branches supply the radial and ulnar arteries.

6 A communicating branch is given to the uhrar nerve.

UTNAR NERVE

The ul:rar nerve is also known as the'musician's nerve'

because it controls fine movembnts of the fingers. Its

course in the palm will be considered in the later part

of this chapter.

Coulse

Ulnar nerve is palpable as it lies behind medial

epicondyle of humerus and is nof a content of cubital

fossa (Fig. 9.13a). It enters the forearm by passing

between two heads of flexor carpi ulnaris, i.e. cubital

tunnel, to lie along the lateral border of flexor carpi

ulnaris in the forearm. In the last phase, it courses

superficial to the flexor retinaculum, covered by its

superficial slip or volar carpal ligament to enter the

region of palm.

Relolions

1 At the elbow, the ulnar nerve lies behind the medial

epicondyle of the humerus. It enters the forearm by

passing between the two heads of the flexor carpi

ulnaris (Fi9.9.13a).

2 In the forearm, the ulnar nerve runs between the

flexor digitorum profundus medially and the flexor

digitorum superficialis laterally.

3 At the wrist, the ulnar neurovascular bundle lies

between the flexor carpi ulnaris and the flexor

digitorum superficialis. The bundle enters the palm

by passing superficial to the flexor retinaculum,

lateral to the pisiform bone.

Lateral root

Median nerve

Anterior

interosseous

nerve

Flexor pollicis

longus

Medial

root

Elbow joint

Pronator teres

Branches to

flexor carpi radialis,

palmaris longus and

flexor digitorum

superficialis

Lateral half of flexor

digitorum profundus

Pronator quadratus

ll

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