Abductor pollicis brevis is innervated by the median nerve, which not only abducts the thumb, but also stops the fibers at the aponeurosis of extensor pollicis, so it has the function of assisting extensor pollicis. When the abduction function of the thumb is restored, the transferred tendon should be fixed on the ulnar side from the radial side of the deep head of the thumb and the base of the proximal phalanx to ensure that the stretching force will not be weakened. Flexor pollicis brevis's superficial head is innervated by the median meridian, and adductor pollicis is innervated by ulnar nerve. In addition, because the directions of abductor pollicis brevis, flexor pollicis brevis, palmar pollicis and oblique head fibers of adductor pollicis are perpendicular to the tiger's mouth, only the transverse head of adductor pollicis and dorsal interosseous muscle of 1 are parallel to the tiger's mouth, so the tendon stops of the latter two muscles are mainly cut off in the operation of enlarging the tiger's mouth. If there are too many avulsion muscle stops, the adduction ability of the stomach will be weakened after operation, and the reconstructed tiger's mouth will be deeply concave "V", which will affect the appearance.
(2) The thenar muscle includes the superficial palmar brevis muscle and abductor digiti minimi, flexor digitorum profundus muscle and palmar digiti minimi muscle, all of which are innervated by ulnar nerve. The contraction of palmaris brevis can make thenar skin depressed and the little finger slightly abduct; Abductor digiti minimi not only spreads the little finger, but also partially stops at the aponeurosis on the dorsal side of the little finger, so it can assist the flexion of the metacarpophalangeal joint and the extension of the finger, showing the function similar to that of vermiform muscle.