Anomalous superficial radial nerve: a patient with probable autosomal dominant inheritance of the anomaly

The sensory symptoms due to lesions of the superficial branch of the radial nerve are usually limited to the dorsolateral area of the hand. We describe a 40-year-old woman who presented with numbness of the dorsomedial aspect of the right hand following arthroplasty of the wrist. Clinically, the sensory loss suggested a lesion of the dorsal branch of the ulnar nerve. However, nerve conduction studies showed that the sensory loss was due to a lesion of a branch of the superficial branch of the radial nerve. The patient had bilateral, anomalous innervation of the dorsum of the hand-the dorsal branch of the ulnar nerve could not be demonstrated with nerve conduction techniques and the superficial branch of the radial nerve innervated most of the dorsum of the hand. Antidromic stimulation of the dorsal branch of the ulnar nerve and superficial branch of the radial nerve with paired surface recording of sensory nerve action potentials from the dorsolateral (radial side) and dorsomedial (ulnar side) hand is useful for evaluating this anomaly. Our patient had two children, one of them with a similar anomaly. This suggests an autosomal dominant inheritance of the anomaly.