Terminal Extensor Tendon Anatomy

Description:

  • The terminal extensor tendon is the distal continuation of the extensor tendon and conjoined lateral bands
  •  The terminal extensor tendon inserts into the base of the distal phalanx and provides extension of the DIP joint.
Diagrams & Photos
  • Note the terminal extensor tendon in purple.
    Note the terminal extensor tendon in purple.
Key Points
  • The terminal extensor tendon laceration or rupture is the cause of a mallet finger injury.
  • Mallet finger injuries can leave the finger with a swan neck deformity.
  • The swan-neck deformity can also be caused by a ruptured volar plate at the PIP joint.
  • The terminal extensor tendon is a very small structure which makes surgical repair difficult even with acute sharp lacerations.
  • Closed injuries to the terminel extensor tendon, like a mallet finger injury, typically shred the terminal tendon making open surgical repair impossible in most cases.  Therefore, mallet fingers are treated with closed extension splinting.
Anatomy References
Anatomic Abbreviations
Hand Surgery Resource Anatomy Diagnostic Guide (Chapter)