Ulnar nerve entrapment neuropathy in the forearm.

A 74-year-old male attorney developed rapidly progressive weakness of the fourth and fifth digits of the right hand with impairment of his grip and ability to perform cursive writing. Lancinating pain occurred spontaneously and was triggered by pressure along the ulnar border of the forearm about 5 cm proximal to the wrist crease. Nerve conduction studies revealed a complete electrical block to stimulation at a point 5 cm proximal to the wrist crease when recording from the abductor digiti minimi. Distal to this point, responses of normal amplitude and latency were recorded. Surgical exploration disclosed two fibrovascular bands coursing from the ulnar artery to the distal belly of the flexor carpi ulnaris, entrapping and grooving the ulnar nerve. Release of these bands resulted in reversal of the electrical block, complete relief of pain, and a full neurologic recovery during the ensuing six months.