The correct answer is 1. The flexor pollicis brevis inserts on the anterior aspect of the base of the proximal phalanx of the thumb and flexes the metacarpophalangeal and carpometacarpal joints of the thumb while also assisting with opposition.
The correct answer is 1. The flexor pollicis brevis inserts on the anterior aspect of the base of the proximal phalanx of the thumb and flexes the metacarpophalangeal and carpometacarpal joints of the thumb while also assisting with opposition.