Musculus extensor digiti medii proprius and musculus extensor digitorum brevis manus - a case report of a rare variation.

The musculus extensor digiti medii proprius and musculus extensor digitorum brevis manus are anomalous extensor muscles of the hand. During the routine dissection of a white male cadaver a musculus extensor digiti medii proprius was seen on both hands and a musculus extensor digitorum brevis manus was seen on the left hand. The extensor medii proprius has a belly originating from the distal third of the ulna near the extensor indicis proprius and its tendon is inserted into the dorsal aponeurosis of the middle finger on both hands. On the left hand there was another anomalous muscle (musculus extensor digitorum brevis manus) which originated from the distal end of the radius, carpal ligaments and carpal joint capsule and inserted on the tendon of the extensor digiti medii proprius. This case is a multivariation of the hand extensor muscles and a musculus extensor digitorum brevis manus inserting on the musculus extensor digiti medii proprius has not been reported previously.