Variations in digital sensory patterns: a study of the ulnar nerve-median nerve palmar communicating branch.

Eighty percent of 50 dissected cadaver palms showed a communicating branch between the fourth and third common digital nerves (ulnar and median origins, respectively). The branch commonly crossed the palm with the superficial arterial arch and usually provided sensory fibers from a branch of the superficial ulnar nerve into the ring finger radial digital nerve. Caution should be taken during carpal tunnel release or other surgery along the axis of the fourth ray to avoid injury to this structure.