- Supinator muscle
Muscle infobox
Name = Supinator muscle
Latin = Musculus supinator
GraySubject = 125
GrayPage = 454
Caption = Posterior view of the supinator.
Caption2 =
Origin =Lateral epicondyle ofhumerus ,supinator crest ofulna ,radial collateral ligament ,annular ligament
Insertion = Lateral proximalradial shaft
Action =Supinates forearm
Antagonist = Pronator teres,pronator quadratus
Blood =Radial recurrent artery
Nerve = Posterior interosseus branch ofradial nerve
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DorlandsPre = m_22
DorlandsSuf = 12551025
The supinator is a broad muscle, curved around the upper third of the radius.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 thelateral epicondyle of the humerus ; from the radial collateral ligament of theelbow-joint , and theannular ligament ; from the ridge on theulna , which runs obliquely downward from the dorsal end of theradial 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 theoblique line of the radius , as low down as the insertion of thepronator 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 supine position.
General use of term
The term "supinator" can also refer more generally to a muscle that causes supination of a part of the body. In older texts, the term "supinator longus" was used to refer to the
brachioradialis , and "supinator brevis" was used to the muscle now known as the supinator.
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