The supinator muscle is a muscle in the forearm that acts to supinate to the forearm.
The supinator originates from the ulna, the humerus, and two nearby ligaments. The supinator is divided into two parts, the deep and the superficial part. The deep part originates from the supinator crest of the ulna and the fossa of the ulna. The superficial part originates from the lateral epicondyle on the distal end of the humerus, the lateral ligament of the elbow and the radial annular ligament.
The supinator is innervated by the posterior interosseous nerve (C5 and C6).