Extensor indicis muscle

The extensor indicis muscle is a muscle in the forearm that extends the index finger, as in a pointing motion.

Origin
The extensor indicis muscle originates from the ulna, on the lower posterior shaft below the origin of the extensor pollicis longus muscle and the interosseous membrane adjacent to it.

Insertion
The extensor indicis muscle inserts on the index finger at the extensor expansion.

Action
The extensor indicis muscle extends all the joints of index finger.

Innervation
The extensor indicis muscle innervated posterior interosseous nerve (C7 and C8).