Forearm ulnar-to-median nerve anastomosis of sensory axons.

A 22-year-old man showed electrophysiological evidence of an ulnar-to-median nerve communication involving only sensory fibers. The nerve action potentials evoked by stimulation of the middle finger (ulnar side) and the ring finger (radial side) digital nerves were propagated with the median nerve at the wrist and the ulnar nerve at the elbow. He was the only subject among 30 studied with this abnormality.