Muscle
Supinator
Rotates the radius into supination
High-yield
The deep radial nerve passes between its layers. The proximal edge of the superficial layer, called the arcade of Frohse, is a recognized site of nerve entrapment.
Overview
This deep muscle curves around the upper radius. It turns the palm toward the front in anatomical position and works with biceps when stronger supination is needed.
Reference facts
- Origin
- Lateral humeral epicondyle, radial collateral and annular ligaments, and the supinator crest and fossa of the ulna
- Insertion
- Anterior, lateral and posterior surfaces of the proximal third of the radius
- Action
- Supinates the forearm; works with biceps, particularly during resisted movement
- Innervation
- Deep radial nerve; chiefly C5-C6, with C7 contributions described
- Blood supply
- Recurrent interosseous and radial recurrent arterial branches
Clinical correlation
Compression around the supinator can weaken finger and thumb extension. Wrist extension may remain but drift radially because extensor carpi radialis longus is supplied more proximally.
Frequently asked questions
What does the supinator do?
Supinates the forearm; works with biceps, particularly during resisted movement.
What nerve innervates the supinator?
Deep radial nerve; chiefly C5-C6, with C7 contributions described.
Where does the supinator attach?
Origin: Lateral humeral epicondyle, radial collateral and annular ligaments, and the supinator crest and fossa of the ulna. Insertion: Anterior, lateral and posterior surfaces of the proximal third of the radius.
What is the blood supply of the supinator?
The supinator is supplied by the recurrent interosseous and radial recurrent arterial branches.