Flexor pollicis brevis muscle

The flexor pollicis brevis muscle is a muscle of the hand that flexes the thumb (brings the thumb toward the palm of the hand) when contracted.

Origin
The flexor pollicis brevis originates from the flexor retinaculum in the wrist and the tubercle of the trapezium bone.

Insertion
The flexor pollicis brevis inserts at the base of the proximal phalanx of the thumb.

Action
The flexor pollicis brevis flexes the metacarpophalangeal joint of the thumb.

Innervation
The flexor pollicis brevis is innervated by the muscular branch of the median nerve (C8 and T1).