Dorsal Ulnar Sensory Nerve Exam

The dorsal ulnar sensory nerve leaves the main ulnar nerve 6-8 cm proximal to the ulnar styloid (6.4 cm. from head of ulna). After separation, this branch passes dorsal to the flexor carpi ulnaris and volar to the ulnar shaft to reach the subcutaneous tissues on the ulnodorsal aspect of the wrist and hand.
The dorsal ulnar sensory nerve supplies sensation to the dorsoulnar part of the wrist and hand, sensation to the dorsal little finger distally to the distal interphalangeal joint area, and sensation to the dorsal ulnar aspect of the ulnar half of the ring finger.
The Ulnar Nerve an extension of the medial cord in the brachial plexus. The medial cord originates from the spinal roots C8 and T1.
When examining the dorsal ulnar sensation use light touch and compare the patients injured side to the uninjured side.
Two point discrimination is not useful on the dorsum of the hand.

Diagrams & Photos

Key Points

Cubital Tunnel Syndrome can cause sensory abnormalities in the distribution of the dorsal ulnar sensory nerve and the palmar ulnar sensory digital nerve branches.
Entrapment of the ulnar nerve at the wrist level in Guyon's canal would only cause sensory abnormalities in the palmar ulnar sensory digital nerve branches.