Anatomy
Origin:
Superficial head (tendinosus): Lateral epicondyle of humerus, Radial collateral and annular ligaments
Deep head (muscular): Supinator crest and fossa of ulna.
Insertion:
Lateral aspect of the proximal third of the radius.
Key Relations:
-The posterior interosseus nerve travels between the two heads of supinator as it enters the posterior forearm.
-One of the six muscles in the deep posterior compartment of the forearm.
Functions
Supination of the extended forearm.
Assists biceps in supination of the flexed forearm.
e.g. as in tightening a screw (right hand)..
Supply
Nerve Supply:
Posterior interosseous nerve (C6,C7) ( continuation of deep branch of the radial nerve).
Blood Supply:
Radial recurrent artery.
Clinical
Compression of the posterior interosseus nerve as it passes between the two heads of suppinator can lead to discomfort, pain, or even a weakness of the extensors of the wrist.
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