Extensor digitorum muscle

Last revised by Assoc Prof Craig Hacking on 24 Aug 2021

Extensor digitorum (ED) muscle, also known as extensor digitorum communis (EDC) muscle, is a muscle of the superficial layer of the posterior compartment of the forearm and with other extensor muscles arises from a common tendon attached to the lateral epicondyle of the humerus. It is one of the extrinsic muscles of the hand.


Gross anatomy

ED represents a medial group of superficial extensor muscles. ED passes under the extensor retinaculum which holds it tight and passes through the 4th extensor compartment of the wrist, once it passes under the sagittal band of the metacarpophalangeal joint the tendon splits into three 'slips' consisting of two lateral slips and a central slip. The lateral slips, run both sides of the proximal interphalangeal joints to then converge with the intrinsic muscles of the hand to form a conjoint tendon, that inserts at the dorsal aspect of the base of the distal phalanx. The central slip inserts at the dorsal surface of the base of the middle phalanx.

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Cases and figures

  • Figure 1: extensor compartments of the wrist
    Drag here to reorder.
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