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Duke Orthopaedics
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Wheeless' Textbook of Orthopaedics

Extensor Digitorum Longus   



- Origin:
     - lateral condyle of the tibia, head and proximal 3/4 of the anterior surface on the body of the fibula, proximal portion of interosseus 
          membrane, deep fascia and intermuscular septa;

- Insertion:
     - divides into 4 tendons after passing under the extensor retinaculum;
     - unlike the EDC, there is no dorsal insertion of the EDL to the proximal phalanx;
          - instead, the proximal phalanx is suspended by the EDL and extensor sling;
          - extensor sling (saggital bands) span either side of the tendon and are anchored to the volar plate of the MTP joint;
     - tendon then divides into 3 slips;
          - central slip inserts into base of middle phalanx;
          - two lateral slips unite and insert onto distal phalanx;

- Nerve supply: peroneal, L5 > L4, S1; (see innervation)

- Action:
    - extends toes at the foot;
    - dorsiflexion and everts foot at the ankle.
    - main action of the EDL is to dorsiflex the phalanx;
          - it is able to dorsiflex the PIP joint only when the phalanx is in a neutral or flexed position;

- Synergist: Extensor Digitorum Brevis



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

Last updated by Data Trace Staff on Thursday, December 8, 2011 12:45 pm