Extensor Indicis Proprius
Extensor Indicis Propius is a narrow elongated skeletal muscle situated in deep layer of posterior compartment of the forearm along with Supinator, Abductor Pollicis Longus, Extensor Pollicis Longus and Brevis. It is responsible for the movement of the index finger. A few variations of Extensor Indicis muscle is observed in people which are classified as -
- Type 1 - An additional tendon slip from the Extensor Indicis tendon
- Type 2 - An Extensor Indicis Radialis or Extensor Pollicis et Indicis Accessorius
- Type 3 - An Extensor Medii Proprius with or without Extensor Medii Brevis
- Type 4 - An Extensor Indicis Radialis and Extensor Medii Proprius.
It is supplied by the Posterior Interosseous branch of the Ulnar artery and perforating branches of the Anterior Interosseous artery.
- The primary function of Extensor Indicis Propius is the extension of second digit at metacarpophalangeal and interphalangeal joints.
- It may assist in wrist extension.
- It assists in abducting the index finger.
- It may assist in slight supination of forearm.
Clinical relevanceThe most common condition affecting Extensor Indicis Propius is Tenosynovitis.
AssessmentMMT (Manual Muscle Testing) of Extensor Indicis muscle is used for assessment.
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