The distribution pattern of the muscular branch of median and ulnar nerves and motor innervation of the thenar and hypothenar muscles were studied in 68 palmar regions taken from 34 adult cadavers of both sexes aged 40 to 70 y. The structure of the flexor pollicis brevis was examined in all 68 hands. In 13 of the 68 hands an anastomosis was seen between the ulnar and median nerves.