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Abductor pollicis brevis



Abductor pollicis brevis - anterior view
Abductor pollicis brevis - lateral view

General information

  • This section is strictly limited to anatomy, you might be looking for clinical relevant information which is found under the clinical chapters -- muscles section, click here to go to that page
  • Part of the thenar musculature


  • Superficial


  • Flexor retinaculum
  • Tuberculum scaphoideum
  • Tuberculum trapezium


  • Proximal phalanx of the thumb - radial side

Main function

  • Thumb CMC
    • Abduction of thumb

Secondary function

  • Thumb
    • Flexion
  • Thumb CMC
    • Extension
  • Thum IP
    • Extension

Nerve innervation

  • Segmental
    • C8-Th1
  • Peripheral
    • Nervus medianus

Arterial supply

  • Radialis artery


  •  Patient position: Sitting or supine
  • Place your hand over the lateral aspect of the thenar eminence
  • Ask your patient to abduct the thumb against your resistance
    • Feel for the contraction
  • Seperate the ulnar part of abductor pollicis brevis from flexor pollicis brevis and opponens pollicis

Strength test

  • Patient position: Sitting or supine
  • Ask the patient to hold the thumb in an abducted position while you are giving resistance towards adduction against the proximal phalanx