Dorsal branch of ulnar nerve

The dorsal branch of ulnar nerve (a.k.a. the dorsal cutaneous branch of ulnar nerve) arises in the distal forearm and plays a key role in providing sensory innervation to the skin of the dorsum of the hand.

Origin and course

The dorsal branch originates from the ulnar nerve above the wrist-level. It travels beneath the tendon of the flexor carpi ulnaris muscle and wraps around to the back of the hand.

Branches and innervation

The dorsal branch of ulnar nerve then pierces the deep fascia to supply the proximal dorsal aspects of the medial 1½ fingers (the little finger and the ulnar half of the ring finger) and the adjoining dorsum of the hand.

Its sensory distribution is further divided into two dorsal digital branches: one innervates the ulnar side of the little finger, while the other supplies the adjacent sides of the little and ring fingers.

Please note that the dorsal aspects of the distal portions of these fingers are innervated by the proper palmar digital nerve branches coming from the palmar side.

Additionally, a communicating branch from the dorsal cutaneous branch connects with the dorsal digital branches of the superficial radial nerve, aiding in the sensory coverage of the hand.