Extensor pollicis brevis

Extensor pollicis brevis (EPB) is one of muscles of the deep layer of the posterior compartment of the forearm, inserting into the base of the proximal phalynx of the thumb. Along with extensor pollicis longus, it is responsible for extension of the thumb. Along with abductor pollicis longus it passes through the 1st extensor compartment of the wrist.

Summary

  • origin: posterior surface of distal radial shaft and interosseous membrane
  • insertion: dorsal surface base of the proximal phalanx of the thumb
  • action: extends the thumb at metacarpophalangeal joint
  • arterial supply: superficial palmar arch
  • innervation: posterior interosseous nerve (C7 and C8), a continuation of the deep branch of the radial nerve (C7, C8)

Upper limb anatomy
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Article Information

rID: 47018
Section: Anatomy
Synonyms or Alternate Spellings:
  • Extensor pollicis brevis muscle

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