label: Flexor Pollicis Brevis Muscle
label_lc: flexor pollicis brevis muscle
description: "A muscle in the hand that has a superficial head that originates from the flexor retinaculum and tubercle of the trapezium bone and a deep head that originates from the trapezoid and capitate bones; it attaches to the lateral side of the base of the proximal phalanx of the thumb and functions to flex the thumb at the metacarpophalangeal joint."