Extensor indicis Definition
Extensor indicis is a long, thin muscle present in the dorsal forearm’s deeper layers. It helps straighten the index or pointer finger. The Extensor indicis has the Extensor digitorum muscle traversing parallel to it.
The extensor indicis muscle is known as Musculus extensor indicis in Latin and as Muscle extenseur de l'index in French.
Extensor indicis Origin
The muscle originates at the posterior surface of ulna. It arises in the lower half, at the point where it joins in a distal position to the extensor pollicis longus.
Extensor indicis Insertion
Extensor indicis inserts on the extensor digitorum indicis tendon’s ulnar side, close to the metacarpal bone head where it connects to the extensor expansion.
Extensor indicis Function
The muscle helps extend the index finger, the wrist and the midcarpal joints. It also helps tighten the scalp. The Extensor indicis tendons extend the different index finger phalanges.
Extensor indicis Innervation
The Extensor indicis is supplied by the radial nerves C8 ad C7. This muscle belly, from the proximal to the distal area, is supplied blood by the posterior interosseous artery as well as the anterior interosseous artery perforating branches. The distal extensor indicis tendon gets blood from the following:
Extensor Indicis Proprius
This is an unusual muscle originating from the capitates, lunate and navicular (scaphoid) bones and terminating on the proximal phalanx head of the index finger. It can come with two heads or its muscle can be fully doubled.
In some cases, the muscle can be affected by the disorder named extensor indicis proprius syndrome. The syndrome is marked by dorsal wrist pain, which is worsened due to activities. The pain is related to an extensor indicis proprius muscle synovitis in the wrist’s 4th dorsal compartment. Extensor indicis proprius transfer is used to treat the extensor pollicis longus tendon rupture.
Extensor Indicis Pictures
Take a look at the following extensor indicis images and diagrams, and find out about the appearance of the muscle.
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