Abductor pollicis brevis

The abductor pollicis brevis is a thin subcutaneous muscle located laterally in the thenar eminence of the hand.


  • origin: mainly from the flexor retinaculum
  • insertion: its medial fibres are attached by a thin, flat tendon to the radial side of the proximal phalangeal base in the pollex and lateral fibres 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

Upper limb anatomy
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Article Information

rID: 42960
Section: Anatomy
Synonyms or Alternate Spellings:

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