The |abductor pollicis brevis| is one of the muscles forming the thenar eminence, the muscle mass of the thumb. The thenar eminence consists of the |abductor pollicis brevis|, the flexor pollicis brevis, and the |opponens pollicis|. The |abductor pollicis brevis| is the largest of the muscle group and is flat, elongated and triangular in shape. It lies just below the skin and slightly overlaps the flexor pollicis brevis and mostly covers the |opponens pollicis|. It moves the metacarpal bone of the thumb away from the palm.
