Extensor Indicis

The Extensor Indicis extends the index finger at the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints. It is a deep forearm extensor and always lies on the ulnar side of the common extensor tendon.

This muscle is a proper (independent) extensor of the index finger. It may act alone or together with the extensor digitorum for movements such as pointing.