The abductor pollicis brevis is a thin subcutaneous muscle located laterally in the thenar eminence of the hand, and is one of the intrinsic muscles of the hand.
Summary
origin: mainly from the flexor retinaculum
few fibers originate from the tubercles of scaphoid and trapezium and tendon of abductor pollicis longus
accessory slips may originate from the long and short pollicial extensors (extensor pollicis longus and extensor pollicis brevis), the opponens pollicis or radial styloid process
insertion: its medial fibers are attached by a thin, flat tendon to the radial side of the proximal phalangeal base in the pollex and lateral fibers join the pollicial dorsal digital expansion
innervation: lateral branch of median nerve (C8 and T1)
action: abducts the thumb and medially rotates it at the carpometacarpal and metacarpophalangeal joints
Summary
origin: mainly from the flexor retinaculum
few fibers originate from the tubercles of scaphoid and trapezium and tendon of abductor pollicis longus
accessory slips may originate from the long and short pollicial extensors (extensor pollicis longus and extensor pollicis brevis), the opponens pollicis or radial styloid process
insertion: its medial fibers are attached by a thin, flat tendon to the radial side of the proximal phalangeal base in the pollex and lateral fibers join the pollicial dorsal digital expansion
innervation: lateral branch of median nerve (C8 and T1)
action: abducts the thumb and medially rotates it at the carpometacarpal and metacarpophalangeal joints
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