Radial artery

At a glance

English

Radial artery

Latin (TA2)

Arteria radialis

System

Artery

Region

Upper limb

Side

Paired, left and right

About the radial artery

The radial artery is the smaller of the two terminal branches of the brachial artery, which divides in the cubital fossa at the front of the elbow. From there it descends along the lateral, thumb-side part of the front of the forearm. Brachioradialis overlaps it above, and towards the wrist it comes to lie under skin and fascia alone, between the tendons of brachioradialis and flexor carpi radialis. Just lateral to it the posterior compartment of the forearm begins, so the vessel is a useful boundary marker. Paired radial veins travel beside it.

At the wrist the artery curves round the lateral side of the carpus, crossing the floor of the anatomical snuffbox, and then dives into the palm by piercing the first dorsal interosseous, between its two heads. It passes forwards between the heads of adductor pollicis and continues as the deep palmar arch, which the ulnar artery's deep palmar branch completes on the medial side.

Its branches fall naturally into three groups. In the forearm it gives the radial recurrent artery, which climbs to meet the radial collateral artery at the elbow, a small palmar carpal branch near pronator quadratus, and the superficial palmar branch, which leaves just before the turn round the wrist and helps complete the superficial arch. At the wrist come the dorsal carpal branch, under the thumb extensor tendons, and the first dorsal metacarpal artery for the facing sides of thumb and index finger. In the palm it gives the princeps pollicis to the thumb and the radialis indicis to the index finger; these two sometimes share a trunk. In under one person in a hundred the artery runs superficially across the snuffbox, where it may be confused with the cephalic vein and injected by mistake.

The radial pulse is taken where the artery lies on the lower end of the radius, and it is a standard way to judge heart rate and rhythm. The same site is used for arterial blood gas samples and for arterial lines in intensive care, because it is easy to reach and seldom clots. An Allen test first checks that the ulnar artery can supply the hand alone. It is also harvested as a coronary bypass graft and used as a route for cardiac catheterisation.

Course and supply

Arises from

The lateral of the two terminal branches of the brachial artery, arising in the cubital fossa at about the level of the neck of the radius.

Ends in

Passes through the first dorsal interosseous and between the heads of adductor pollicis to continue as the deep palmar arch, completed by the deep palmar branch of the ulnar artery.

Supplies

Supplies the lateral muscles of the forearm, the elbow and wrist anastomoses, the thumb and the radial side of the index finger, and most of the deep palmar arch.