Little Extensor Tendon (Combined EDC & EDM ) Anatomy

EDC:

  • Origin
    • Humerus (lateral epicondyle via common extensor tendon)
    • Intermuscular septum
    • Antebrachial fascia
  • Insertion: Base of the middle and distal phalanges of the middle (long) and ring fingers
  • Innervation: Cervical root(s): C7 and C8 Nerve: radial nerve (posterior interosseous branch)
     

EDM:

  • Origin 
    • Humerus (lateral epicondyle via common extensor tendon)
    • Intermuscular septum
  • Insertion: 5th digit (extensor hood)
  • Innervation: Cervical root(s): C7 and C8
  • Nerve: radial nerve (posterior interosseous branch)
Diagrams & Photos
  • EDC & EDM
Key Points

EDC

  •  EDC extends the index, long, ring, and little fingers simultaneously.

EDM

  • EDM has two slips 70% of the time.
  • The brain has independent control over the EDM
Anatomy References
Anatomic Abbreviations
Hand Surgery Resource Anatomy Diagnostic Guide (Chapter)