A variant of the motor branch of the median nerve in the hand.

Variations in the pattern of nerve supply to the hand are common and are of importance in hand surgery. A variant of the motor branch of the median nerve was recently observed twice, at dissection and again during an operation. According to the usual descriptions (Quain 1895, Testut and Latarjet 1949, Hollinshead 1958, Gray 1962, Kaplan 1965), in the palm the median nerve divides into two parts, deep to and approximately at the distal border of the flexor retinaculum. In the majority of cases these subsequently give rise to four to five terminal branches. The motor (or recurrent) branch arises from the anterior surface of the lateral part, follows a short course laterally and supplies some of the thenar muscles. During this course it separates from its nerve of origin and passes around the distal border of the flexor retinaculum.