Human Anatomy Vol 1

UPPER LIMB

Capitulum

Anterolateral surface

Brachioradialis

Lateral supracondylar ridge

Extensor carpi radialis longus

Common extensor origin for:

Extensor carpi radialis brevis

Extensor digitorum

Extensor digiti minimi

Extensor carpi ulnaris

Fig. 9.57: Right humerus, lower end, seen from the lateral side,

to show the origins of the seven superficial muscles of the forearm

DISSECTION

Separate extensor carpi radials brevis from extensor

digitorum and identify deeply placed supinator muscle.

Just distal to supinator is abductor pollicis longus.

Other three muscles: extensor pollicis longus, extensor

pollicis brevis and extensor indicis are present distalto

abductor pollicis longus. ldentify them all.

Feotules

These are as follows:

L Supinator

2 Abductor pollicis longus (Fig. 9.58)

3 Extensor pollicis brevis

4 Extensor pollicis longus

5 Extensor indicis

In contrast to the superficial muscles, none of the

deep muscles cross the elbow joint. These have been

tabulated in Tables 9.1,1, and9.12.

Dorsol Digito! Exponsion

The dorsal digital expansion (extensor expansion) is a

small triangular aponeurosis (related to each tendon

of the extensor digitorum) covering the dorsum of the

proximal phalanx. Its base, which is proximal, covers

the metacarpophalangeal (MP)joint. The main tendon

of the extensor digitorum occupies the central part of

the extension, and is separated from the MP joint by a

bursa.

The posterolateral corners of the extensor expansion

are joined by tendons of the interossei and of lumbrical

muscles. The corners are attached to the deep transverse

metacarpal ligament. The points of attachment of the

interossei (proximal) and lumbrical (distal) are often

called 'wing tendons' (Fig.9.59).

Near the proximal interphalangeal joint the extensor

tendon divides into a central slip and two collateral

Lateral surface of olecranon process of ulna

Base of styloid process of radius

Posterior surface of base of second metacarpal

bone

Posterior surface of base of third metacarpal

Bases of middle phalanges of the 2nd-5th digits

Extensor expansion of little finger

Base of fifth metacarpal bone

Anconeus

Muscle

1. Anconeus


2. Brachioradialis


3. Extensor carpi radialis
   longus


4. Extensor carpi radialis brevis


5. Extensor digitorum


6. Extensor digiti minimi


7. Extensor carpi ulnaris

Thble 9.9: Attachments of

Origin

Lateral epicondyle of humerus

Upper 2l3rd of lateral supracondylar ridge

of humerus

Lower 1/3rd of lateral supracondylar ridge of

humerus

Lateral epicondyle of humerus

Lateral epicondyle of humerus

Lateral epicondyle of humerus

Lateral epicondyle of humerus

Muscle

1. Anconeus


2. Brachioradialis


3. Extensor carpi radialis longus


4. Extensor carpi radialis brevis


5. Extensor digitorum


6. Extensor digiti minimi


7. Extensor carpi ulnaris

Nerue supply

Radial nerue

Radial nerue

Radial nerve

Deep branch of radial nerve

Deep branch of radial nerve

Deep branch of radial nerve

Deep branch of radial nerve

Actions

Extends elbow joint

Flexes forearm at elbow joint; rotates forearm to the

midprone position from supine or prone positions

Extends and abducts hand at wrist joint

Extends and abducts hand at wrist joint

Extends fingers of hand

Extends metacarpophalangeal joint of little finger

Extends and adducts hand at wrist joint

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