The extensor indicis is a muscle within the deep compartment of the posterior forearm.
The tendon of the extensor indicis passes through the 4th extensor compartment at the wrist. It allows extension of index finger to be independent of the other digits.
- Attachments: Originates from the posterior surface of the ulna and interosseous membrane. Attaches to the extensor hood of the index finger.
- Actions: Extension of the index finger at the interphalangeal and metacarpophalangeal joints.
- Innervation: Radial nerve (posterior interosseous branch).
- Blood supply: Ulnar artery