Hand Exam: Motor 7/13 – Extensor Pollicis Brevis (EPB) and Abductor Pollicis Longus (APL)

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Thenar Muscles: Instruct the patient “Bring your thumb out to the side”
All supplied by posterior interosseous branch of the radial nerve 

Abductor Pollicis Longus (APL)

  • Insertion: base of the 1st metacarpal
  • Action: extension of the 1st metacarpal and helps with abduction
  • Innervation: posterior interosseous branch of the radial nerve

Extensor Pollicis Brevis (EPB)

  • Insertion: base of the proximal phalanx of thumb
  • Action: combines with EPL to extend thumb IP joint
  • Innervation: posterior interosseous branch of the radial nerve

The 13 muscle groups you need to test in the hand exam:

  1. FPL
  2. FDP
  3. FDS
  4. Thenar muscles
  5. Interosseous
  6. Hypothenar muscles
  7. EPB and APL
  8. EPL
  9. EDC
  10. EIP and EDM
  11. ECRL and ECRB
  12. ECU
  13. Adductor Pollicis

5 thoughts on “Hand Exam: Motor 7/13 – Extensor Pollicis Brevis (EPB) and Abductor Pollicis Longus (APL)”

  1. Pingback: Hand Exam: Motor 9/13 – Extensor Digitorum Communis (EDC) | Sketchy Medicine

  2. Pingback: Hand Exam: Motor 1/13 – Flexor Pollicis Longus (FPL) | Sketchy Medicine

  3. Pingback: Hand Exam: Motor 8/13 – Extensor Pollicis Longus (EPL) | Sketchy Medicine

    • Oh wow, you’re completely right! Embarrassing to have that typo considering I now do tons of hand exams every single day. I’ve fixed it now.

      Reply ↓

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