The Hip: Preservation, Replacement and Revision

Extensor Digitorum Communis

- See:
      - Forearm Extensors:
      - Extensor Tendon Laceration

- origin: lateral epicondyle of humerus;
- tunnel IV:
    - narrow retinaculum over dorsum of wrist forms pulley system for extensor tendons;
    - above the wrist its four slips spread out joined together by juncturae;
    - just ulnar to tunnel III & just radial to radioulnar articulation, transports EDC & EIP to the hand;
    - junctura tendinae:
          - origin: most commonly from extensor tendon of ring finger;
          - insertion: juncture diverge from ring finger, & go on to attach to extensor tendons of middle and little digits.
          - function:
                - limits independent extension of ulnar 3 digits;
                - flexion of middle & little fingers at MCP joint, prevent its independent extension of ring finger;

- Junctura Tendinae:
     - origin: most commonly from extensor tendon of ring finger to adjacent digits, arising just proximal to MCP joints;
     - juncture diverge from ring finger, & go on to attach to extensor tendons of middle and little digits.
     - there also usually a junctura between index and long fingers;
     - EIP has no junctura;
     - lacerations of middle or little digits proximal to junctura;
           - finger extension of these digits still may exist thru ring finger junctura tendinae contributing to distal ends of cut tendons of middle or little digits;

- Extensor Mechanism of Digitis

- nerve supply: deep radial nerve, C6, C7, C8;

- action: extends the metacarpophalangeal and carpometacarpal articulations;

- synergists: Extensor Indicis , Extensor Digiti Minimi , Lubricals

Rupture of digital extensor tendons following distal ulnar resection.

Bilateral Extensor Digitorum Brevis Manus

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Friday, September 21, 2012 10:07 am