Human Anatomy Vol 1

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UPPER LIMB

Humerus

Lateral epicondyle

Capitulum

Radial collateral ligamenl

Annular ligament

Radius

Fig. 10.12: The radial collateral ligament of the elbow joint

3 The radinl collateral or lateral ligament: It is a fan-shaped

band extending from the lateral epicondyle to the

annular ligament. It gives origin to the supinator and

to the extensor carpi radialis brevis (Fig. 10.12).

Relolions

. Anterioily; Brachialis, median nerve, brachial artery
and tendon of biceps brachii (see Fig.9.4).
o Posteriorly; Triceps brachii and anconeus.
. Medially; Ulnar nerve, flexor carpi ulnaris and
common flexors.
. Laternlly: Supinator, extensor carpi radialis brevis and
other common extensors.

Blood Supply

From anastomoses around the elbow joint (see Fig. 8.10).

Nerve Supply

The joint receives branches from the following nerves.

i. Uhrar nerve.

ii. Median nerve.

iii. Radial nerve.

iv. Musculocutaneous nerve through its branch to the

brachialis.

Movemenls

1 Flexion is brought about by:

i. Brachialis.

ii. Biceps brachii.

iii. Brachioradialis.

2 Extension is produced by:

i. Triceps brachii.

ii. Anconeus.

Fig. 10.13: Carrying angle

Corrying Angle

The transverse axis of the elbow joint is directed

medially and downwards. Because of this the extended

forearm is not in straight line with the arm, but makes

an angle of about^13 degrees with it. This is known as

the carrying angle. The factors responsible for formation

of the carrying angle are as follows.

a. The medial flange of the trochlea is^6 mm deeper

than the lateral flange.

b. The superior articular surface of the coronoid process

of the ulna is placed oblique to the long axis of the

bone.

The carrying angle disappears in full flexion of the

elbow, and also during pronation of the forearm. The

forearm comes into line with the arm in the midprone

position, and this is the position in which the hand is

mostly used. This arrangement of gradually increasing

carrying angle during extension of the elbow increases

the precision with which the hand (and objects held in

it) can be controlled (Fig. 10.13).

. Distension of the elbow joint by an effusion
occurs posteriorly because here the capsule is
weak and the covering deep fascia is thin.
Aspiration is done posteriorly on any side of the
olecranon (Fig. 10.1a).
o Dislocatio,n of the elbow is usually posterior, and
is often associated with fracture of the coronoid
process. The triangular relationship between the
olecranon and the two humeral epicondyles is lost
(see Fi9,2.19).