The flexor pollicis brevis is a muscle in the hand that flexes the thumb. It is one of three thenar muscles. It has both a superficial part and a deep part.

What does the flexor pollicis brevis muscle do?

Function. Flexor Pollicis Brevis flex the metacarpophalangeal and carpometacarpal joints leading to the opposition of the thumb and, if continued, produces the medial rotation of the thumb. Due to this function, we are able to manipulate objects and create tools.

What causes flexor pollicis brevis pain?

Injuries to flexor pollicis brevis can include strain, tears, atrophy, infectious myositis, and overuse. Injury should be suspected when hand or thumb pain is present or if there is decreased flexion of the thumb.