ABDUCTOR POLLICIS BREVIS :
The abductor pollicis brevis is a muscle in the hand that functions as an abductor of the thumb.
ORIGIN :transverse carpal ligament and scaphoid and trapazium
INSERTION : radial base of proximal phalanx of thumb and thumb extensors
NERVE SUPPLY : recurrent branch of median nerve
ACTION/EXERCISE : abduction of thumb by acting across the carpometacatpal jointand metacarpophalangeal joint.
it is also assest opposition and extension of the thumb.