Extensor digitorum
Arms
- Origin
- Lateral epicondyle of the humerus (common extensor origin)
- Insertion
- Extensor expansions of the four fingers
- Action
- Extends the fingers and assists wrist extension
- Nerve supply
- Posterior interosseous nerve (radial nerve, C7–C8)
The main finger extensor, running down the middle of the back of the forearm. Its tendons show on the back of the hand when you spread your fingers.