Ulnar artery

At a glance

English

Ulnar artery

Latin (TA2)

Arteria ulnaris

System

Artery

Region

Upper limb

Side

Paired, left and right

About the ulnar artery

The ulnar artery carries oxygenated blood down the medial part of the forearm into the hand. It begins in the cubital fossa, a little below the elbow crease, as the larger of the two branches into which the brachial artery divides. From there it slants downward and medially, reaching the ulnar border of the forearm about halfway to the wrist, and then runs straight down to the wrist. It crosses in front of the flexor retinaculum just lateral to the pisiform and, immediately beyond that bone, splits into a superficial branch that forms most of the superficial palmar arch and a deep branch that helps complete the deep arch. Two venae comitantes travel with it.

In the upper forearm the artery lies deep: brachialis and flexor digitorum profundus form its bed, while the superficial flexors cover it, namely pronator teres, palmaris longus, flexor carpi radialis and flexor digitorum superficialis. The median nerve lies medial to it at first and then crosses it, with the deep (ulnar) head of pronator teres between them. In the lower half its bed is still flexor digitorum profundus, with flexor digitorum superficialis on its lateral side and flexor carpi ulnaris medially, the latter overlapping it in the middle third. The ulnar nerve runs along its medial side for the lower two-thirds and stays medial and slightly behind it at the wrist, with the pisiform medial to both. Here the artery is covered only by skin, fascia and the palmar carpal ligament and can be felt pulsing.

Its forearm branches are the anterior and posterior ulnar recurrent arteries to the elbow anastomosis, and the short common interosseous artery, which at once gives the anterior and posterior interosseous arteries. Near the wrist it sends palmar and dorsal carpal branches to the carpal arches. In the hand the deep palmar branch slips between the hypothenar muscles and joins the deep arch.

Variations are more frequent than in the radial artery. The vessel may arise high, from the brachial or rarely the axillary artery, and then usually runs superficial to the flexor muscles, sometimes just under the skin, where it is at risk from injections. At the wrist it shares Guyon's canal with the ulnar nerve. Its patency is checked in the Allen test before radial procedures.

Course and supply

Arises from

The larger, medial terminal branch of the brachial artery, arising in the cubital fossa at about the neck of the radius.

Ends in

Divides just beyond the pisiform into its superficial branch, which forms most of the superficial palmar arch, and its deep palmar branch, which joins the deep palmar arch.

Supplies

Supplies the medial forearm muscles, the elbow and carpal anastomoses, the interosseous territory of both forearm compartments, and most of the palm and medial fingers through the superficial arch.