Ulnar artery

Arteria ulnaris

CardiovascularBlood vesselsArmLeft and right

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What it is

The larger terminal branch of the brachial artery; it passes deep to the flexor muscles, descends along the medial (little-finger) side of the forearm with the ulnar nerve and crosses the wrist superficial to the flexor retinaculum beside the pisiform bone.

Function

Supplies the medial forearm (including the common interosseous artery) and forms most of the superficial palmar arch.

Size

~3 mm diameter; ~23 cm long.

Clinical note

The Allen test checks that the ulnar artery alone can supply the hand before the radial artery is cannulated or harvested for bypass grafts.