GLOSSARY

The extensor digitorum is the main muscle of the back of the forearm; with four tendons it extends the second to fifth fingers, and its tendons are visible on the back of the hand when the fingers are straightened.

Attachments and Innervation

• Origin: the lateral epicondyle of the humerus (common extensor tendon).
• Insertion: via the extensor mechanism (extensor hood) to the middle and distal phalanges of the second to fifth fingers.
• Nerve: the posterior interosseous nerve (C7 and C8).

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