Abductor pollicis longus

  • The abductor pollicis longus (or abductor pollicis longus muscle, latin: musculus abductor pollicis longus) is a flat muscle of the forearm that belongs to the posterior muscle group, lying in the second or deep layer.

    Origin

    The abductor pollicis longus originates from the posterior surfaces of the ulna and radius and the interosseous membrane of the forearm.

    Insertion

    The abductor pollicis longus descends obliquely and ends in a slim tendon that passes vertically downwards to reach the dorsal surface of the hand. The tendon of the abductor pollicis longus inserts at the base of the first metacarpal bone.

    Action

    The main function of the abductor pollicis longus is to abduct the thumb.

    Innervation

    The abductor pollicis longus is innervated by the radial nerve.