Extensor Pollicis Brevis

• O (origin):

  • Posterior aspect of middle 1/3 of radius
  • Adjacent interosseous membrane

  A) Extensor Pollicis Brevis

  
• R (direction):

  • Distally

  A) Extensor Pollicis Brevis

  
• I (insertion):

  • Dorsal aspect base of proximal phalanx of thumb

  A) Extensor Pollicis Brevis

  
• A (action):

  • Extension of 1st metacarpophalangeal and carpometacarpal joints

  A) Extensor Pollicis Brevis

  
• NS (nerve supply):

  • Posterior interosseous branch of radial nerve (C5 - T1)

  A) Extensor Pollicis Brevis