Supinator (Musculus supinator)
Educational content only — not medical advice.
Anatomy
A deep muscle at the forearm base wrapping two layers around the radial neck, with the radial deep branch (posterior interosseous nerve) passing between them — the classic entrapment point of radial-tunnel syndrome.
Origin & insertion
Lateral epicondyle, radial collateral and annular ligaments and the supinator crest of the proximal ulna.
Action
Supinates the forearm slowly under load — it owns slow heavy supination; the biceps generates fast supination.
Innervation
Radial nerve — posterior interosseous branch (C5–C6).
Clinical notes
Nerve entrapment between its layers begins with finger-extensor weakness without wrist drop — distinguishing partial from complete deep-branch palsy is decisive before surgery.
Related structures
Educational references
FAQ
What is the role of the Supinator?
A deep muscle at the forearm base wrapping two layers around the radial neck, with the radial deep branch (posterior interosseous nerve) passing between them — the classic entrapment point of radial-tunnel syndrome.
Why is the Supinator clinically important?
Nerve entrapment between its layers begins with finger-extensor weakness without wrist drop — distinguishing partial from complete deep-branch palsy is decisive before surgery.
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