Extensor indicis
Arms
Deep muscle — it lies under other muscles. X-ray makes the muscles over it see-through.
- Origin
- Back of the lower ulna and the interosseous membrane
- Insertion
- Extensor expansion of the index finger
- Action
- Extends the index finger; helps extend the wrist
- Nerve supply
- Posterior interosseous nerve (radial nerve, C7–C8)
A small, deep forearm muscle that lets the index finger straighten on its own, as when pointing.
Extensor indicis anatomy page →