AnatomyDeck

Muscle

Extensor digitorum

Main finger extensor

Upper limbMuscular system

High-yield

Extends the MCP joints of the four fingers via extensor expansions; posterior interosseous nerve (deep radial).

Overview

The principal extensor of the fingers, its four tendons crossing the dorsum of the hand and forming the extensor expansions.

Reference facts

  • Origin

    Lateral epicondyle of the humerus (common extensor origin)

  • Insertion

    Extensor expansions of the medial four fingers (middle and distal phalanges)

  • Action

    Extends the fingers at the MCP joints and assists wrist extension

  • Innervation

    Posterior interosseous nerve (deep branch of radial, C7, C8)

  • Blood supply

    Posterior interosseous artery

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