It is a larger terminal branch of the brachial artery and begins a little below the bend of the elbow (knee joint), in the cubital fossa (triangular area in front of the knee joint). It runs down the whole length of the forearm (on medial side) to reach the ulnar border (medial side) of the wrist, from where it enters the palm by passing superficial to the flexor retinaculum and crosses the pisiform bone, immediately beyond this bone, it divides into two branches i.e. superficial palmar branch (makes superficial palmar arch by joining superficial branch of the radial artery) and deep palmar branch (makes deep palmar arch by joining terminal part of radial artery).

RELATIONS

In the forearm:

Along its course, it is accompanied by two venae comitantes and ulnar vein. Anteriorly, upper half is covered by muscles arising from common flexor origin (pronator teres, Palmaris longus etc), median nerve and lower half is superficial, covered only by the skin and fascia. Posterior to it, brachialis and flexor digitorum muscles are present. Medially, ulnar nerve and flexor carpi ulnaris are present. Laterally, flexor digitorum superficialis are present.

At the wrist:

Artery is covered by skin and volar carpal ligament, lies upon flexor retinaculum of the hand, on medial side is pisiform bone and posterior to it is ulnar nerve.

BRANCHES

In the forearm:

• The anterior and posterior ulnar recurrent arteries

• The common interosseous artery (further divides into anterior and posterior interosseous artery)

• Muscular branches

At the wrist and in the hand:

• Palmar and dorsal carpal branches

• Terminal branches as described above.

AREA SUPPLIED BY ULNAR ARTERY

All these branches supply the area around the elbow (knee joint), flexor and extensor muscles on medial side of the forearm along its course and finally to the structures of the hand (in hand supplies with radial artery).