Extensor indicis (Musculus extensor indicis)
Educational content only — not medical advice.
Anatomy
A narrow deep muscle below extensor pollicis longus; its slim tendon joins the index expansion, granting the finger independent pointing without dragging the other fingers.
Origin & insertion
Lower third of the posterior ulna and the interosseous membrane.
Action
Extends all index phalanges and assists precise pickup.
Innervation
Radial nerve — posterior interosseous branch (C7–C8).
Clinical notes
Its tendon transfer is standard in rebuilding lost thumb tendons; distinguishing its action from extensor digitorum explains the "independent index extension" targeted after nerve repair.
Related structures
Educational references
FAQ
What is the role of the Extensor indicis?
A narrow deep muscle below extensor pollicis longus; its slim tendon joins the index expansion, granting the finger independent pointing without dragging the other fingers.
Why is the Extensor indicis clinically important?
Its tendon transfer is standard in rebuilding lost thumb tendons; distinguishing its action from extensor digitorum explains the "independent index extension" targeted after nerve repair.
Source & license
BodyParts3D, © The Database Center for Life Science licensed under CC Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/). license details