Supinator

The supinator (Latin: musculus supinator) is a small muscle of the forearm that extends between the distal humerus and proximal radius and ulna. It belongs to the posterior compartment of the forearm muscles, lying in the second (deep) layer. As the name suggests, the supinator provides the supination of the forearm.

Origin

The supinator originates from the lateral epicondyle of the humerus, radial collateral and annular ligaments and the supinator crest of the ulna.

Insertion

The supinator inserts on the lateral, anterior and posterior surfaces of the proximal one-third of the radius.

Action

The supinator muscle provides the forearm supination at the proximal radioulnar joint.

Innervation

The supinator is innervated by the posterior interosseous nerve, which is a branch of the radial nerve (C7, C8).

Blood supply

The supinator muscle receives arterial blood supply from the radial recurrent, posterior interosseous and interosseous recurrent arteries. The first artery is a branch of the radial artery, while the second arises from the common interosseous artery. The latter is a branch of the posterior interosseous artery.