Abstract: During the period form April to June 1979, we successfully transplanted free myocutaneous flaps of M. extensor digitorum brevis for the restoration of the functions of thenar muscles and adductor pollicis in 3 cases. All these three patients were injured before, and the functions of these muscles have been lost completely. The operative procedure included flap design, fine exposure and anastomosis of vessels and nerves, skin grafting and closure of the wound and other delicate technics. In addition to ensuring the vascular patency, it is necessary to take care of the nerve branches innervating M. extensor digitorum brevis to restore its motor functions. It is important to preserve the sensory nerve fibers connecting with the flap to restore the sensory functions. All these 3 cases were followed up for 2 years, and normal potentials were observed electromyographically, indicating that the motor nerves have regenerated after surgery. The transplanted muscles showed a strength of 3—4 grade with active motion of the thumbs, and the sensations have been restored.