Origin

Supraspinous fossa of scapula

Insertion

Superior facet of greater tubercle of humerus

Action(s)

Contraction of the supraspinatus muscle leads to abduction of the arm at the shoulder joint. It is the main agonist muscle for this movement during the first 30 degrees of its arc. Beyond 30 degrees the deltoid muscle becomes increasingly more effective at abducting the arm and becomes the main propagator of this action.

The supraspinatus muscle is one of the musculotendinous support structures called the rotator cuff that surround and enclose the shoulder. It helps to resist the inferior gravitational forces placed across the shoulder joint due to the downward pull from the weight of the upper limb.

The supraspinatus also helps to stabilize the shoulder joint by keeping the head of the humerus firmly pressed medially against the glenoid fossa of the scapula.

Nerve Supply

The supraspinatus muscle is supplied by the suprascapular nerve (C5 and C6), which arises from the superior trunk of the brachial plexus and passes laterally through the posterior triangle of the neck and through the scapular notch on the superior border of the scapula. After supplying fibers to the supraspinatus muscle, it supplies articular branches to the capsule of the shoulder joint.

This nerve can be damaged along its course in fractures of the overlying clavicle, which can reduce the person’s ability to initiate the abduction.

Arterial Supply

Suprascapular artery

Physical Exam

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Clinical Importance

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Discussion

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Figures

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From Wikipedia:
Supraspinatus

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Supraspinatus.png (image/png)