Dorsal digital branches of radial nerve

At a glance

English

Dorsal digital branches of radial nerve

Latin (TA2)

Rami digitales dorsales nervi radialis

System

Nerve

Region

Upper limb

Side

Paired, left and right

About the dorsal digital branches of radial nerve

The dorsal digital branches of the radial nerve are the final twigs of the superficial branch of the radial nerve. That branch runs down the forearm under brachioradialis, emerges from beneath its tendon about seven centimetres above the wrist, and crosses the roof of the anatomical snuffbox onto the back of the hand. There it divides into four or five dorsal digital nerves.

Their usual arrangement is as follows. One runs along the radial side of the back of the thumb, another along its ulnar side. A third supplies the radial side of the index finger, a fourth the adjacent sides of the index and middle fingers, and a fifth, when present, the facing sides of the middle and ring fingers, where it communicates with a twig of the dorsal branch of the ulnar nerve. They run beside the dorsal digital arteries.

On the fingers they reach only the proximal parts. On the thumb they may extend to the base of the nail, but on the index, middle and ring fingers the skin over the middle and distal phalanges is supplied by palmar digital branches of the median nerve that curve onto the back. The radial territory on the dorsum therefore covers the lateral part of the back of the hand and the proximal dorsal skin of the lateral three and a half digits, with much overlap.

These nerves lie just beneath the skin over the radial side of the wrist and thumb, so they can be compressed by a tight watch strap or handcuffs, producing numbness and tingling over the back of the thumb, a condition called cheiralgia paraesthetica. They can also be injured when cannulas are inserted into the cephalic vein near the wrist or during surgery for de Quervain's tenosynovitis.

Course and supply

Arises from

The superficial branch of the radial nerve on the back of the wrist (fibres mainly from C6 to C8).

Ends in

End in the skin of the back of the thumb and the proximal backs of the index, middle and lateral half of the ring fingers.

Supplies

Sensory to the dorsal skin of the thumb and the proximal dorsal skin of the index, middle and part of the ring fingers; no muscle supply.