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Supinator muscle
Gray420.png
Posterior view of the supinator. (Right arm.)
Latin Musculus supinator
Gray's subject #125 454
Origin Lateral epicondyle of humerus, supinator crest of ulna, radial collateral ligament, annular ligament
Insertion    Lateral proximal radial shaft
Artery Radial recurrent artery
Nerve deep branch of radial nerve
Actions Supinates forearm
Antagonist Pronator teres, pronator quadratus

The supinator is a broad muscle, curved around the upper third of the radius.

Contents

Origin and insertion

It consists of two planes of fibers, between which the deep branch of the radial nerve lies. The two planes arise in common—the superficial one by tendinous (the initial portion of the muscle is actually just tendon) and the deeper by muscular fibers—from the lateral epicondyle of the humerus; from the radial collateral ligament of the elbow-joint, and the annular ligament; from the ridge on the ulna, which runs obliquely downward from the dorsal end of the radial notch; from the triangular depression below the notch; and from a tendinous expansion which covers the surface of the muscle.

The superficial fibers surround the upper part of the radius, and are inserted into the lateral edge of the radial tuberosity and the oblique line of the radius, as low down as the insertion of the pronator teres.

The upper fibers of the deeper plane form a sling-like fasciculus, which encircles the neck of the radius above the tuberosity and is attached to the back part of its medial surface; the greater part of this portion of the muscle is inserted into the dorsal and lateral surfaces of the body of the radius, midway between the oblique line and the head of the bone.

Action

The action of the supinator is suggested by its name; it assists the biceps in bringing the hand into the prone position. It Pronates the forearm.

General use of term

The term "supinator" can also refer more generally to a muscle that causes pronation of a part of the body. In older texts, the term "pronator longus" was used to refer to the brachioradialis, and "pronator brevis" was used to the muscle now known as the pronator.

Additional images

External links

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.

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