The abductor pollicis brevis is a flat, thin muscle located just under the skin.

It originates from the flexor retinaculum of the hand, the tubercle of the scaphoid bone, and additionally sometimes from the tubercle of the trapezium.

Running lateralward and downward, it is inserted by a thin, flat tendon into the lateral side of the base of the first phalanx of the thumb, and the capsule of the metacarpophalangeal joint.

The abductor pollicis brevis is supplied by the recurrent branch of the median nerve (Roots C8-T1).

This article incorporates text in the public domain from page 461 of the 20th edition of Gray's Anatomy (1918)