Abductor pollicis brevis muscle

Radiopaedia • CC-by-nc-sa 3.0 • de

The abductor pollicis brevis muscle 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