Flexor pollicis brevis
A hand muscle, the flexor pollicis brevis muscle flexes the thumb at the metacarpophalagneal joint. This is in opposition to the extensor pollicis brevis muscle, which extends the thumb. Damage to this muscle would impair the thumb's ability to move. Since the thumb is the most versatile and often used digits of the hand, many actions involving the hand would either become more difficult or impossible. The flexor pollicis brevis originates at the flexor retinaculum of the hand, which is a band of fibers that stretch over the hand's carpus. Also, the muscle possesses an origination point at the trapezoid carpal bone, and it inserts into the thumb's proximal phalanx bone. With a continuous supply of oxygenated blood, the superficial palmar arch services the muscle. Plus, the superficial palmar venous arch assists in draining deoxygenated blood away. As for innervations, the flexor pollicis brevis muscle uses both the recurrent branch of the median nerve and the deep branch of the ulnar nerve.
Written and medically reviewed by the Healthline Editorial Team
In Depth: Flexor pollicis brevis