extensor indicis proprius
Small muscle tendon that provides independent extension to the index finger, commonly used for tendon transfers.
Full Definition
The extensor indicis proprius (EIP) is a small muscle in the deep compartment of the posterior forearm that provides independent extension to the index finger. This tendon runs ulnar to the extensor digitorum communis tendon to the index finger and inserts into the extensor mechanism. The EIP is clinically significant because it allows for isolated index finger extension when the other fingers are flexed, and it serves as an excellent donor tendon for various reconstructive procedures due to its expendable nature and good excursion. Common uses include tendon transfers for thumb extension reconstruction, particularly in cases of extensor pollicis longus rupture or radial nerve paralysis. The muscle is innervated by the posterior interosseous nerve.
Usage
Usage note: May be abbreviated as EIP; distinguish from other extensor tendons when describing tendon transfers.
In Context
- "The extensor indicis proprius was harvested and transferred to restore thumb extension function." — Operative report
- "Independent index finger extension confirmed intact extensor indicis proprius function." — Physical examination