MuscleForearm — posterior
Extensor digitorum
Latin: M. extensor digitorum
Location: Forearm
View the extensor digitorum in 3DOrigin
Lateral epicondyle of the humerus (common extensor origin).
Insertion
Extensor expansions of the medial four fingers — a central slip to the middle phalanx and lateral bands to the distal phalanx.
Action
Extends the MCP joints of the fingers, extending IP joints with lumbrical cooperation; the hand-opening muscle.
Nerve supply
Posterior interosseous nerve (C7–C8).
Blood supply
Posterior interosseous artery.
Clinical relevance
Its tendon slips drift ulnar-ward in rheumatoid arthritis — ulnar drift; sagittal band ruptures at the knuckle cause extensor subluxation.
Educational anatomy reference, not medical advice. About this content.