Superficial Branch of Radial Nerve - Medial Branch

The medial branch communicates, above the wrist, with the dorsal branch of the lateral antebrachial cutaneous, and, on the back of the hand, with the dorsal branch of the ulnar nerve.

It then divides into four digital nerves, which are distributed as follows: the first supplies the ulnar side of the thumb; the second, the radial side of the index finger; the third, the adjoining sides of the index and middle fingers; the fourth communicates with a filament from the dorsal branch of the ulnar nerve, and supplies the adjacent sides of the middle and ring fingers.