Supraspinatus Muscle Function & Trigger Points

 The supraspinatus is a relatively small muscle of the upper back that runs from the supraspinatous fossa superior portion of the scapula (shoulder blade) to the greater tubercle of the humerus. It is one of the four rotator cuff muscles and therefor help to stablize the glenohumeral jount , it also abducts the arm at the shoulder. The spine of the scapula separates the supraspinatus muscle from the infraspinatus muscle, which originates below the spine.

Structure
The supraspinatus muscle arises from the supraspinous fossa, a shallow depression in the body of the scapula above its spine. The supraspinatus tendon passes laterally beneath the cover of the acromion. The supraspinatus tendon is inserted into the superior facet of the greater tubercle of the humerus. The distal attachments of the three rotator cuff muscles that insert into the greater tubercle of the humerus can be abbreviated as SIT when viewed from superior to inferior (for supraspinatus, infraspinatus, and teres minor), or SITS when the subscapularis muscle, which attaches to the lesser tubercle of the humerus, is included.

Function
The supraspinatus muscle performs abduction of the arm, and pulls the head of the humerus medially towards the glenoid cavity. It independently prevents the head of the humerus to slip inferiorly. Supraspinatus works in cooperation with the deltoid muscle to perform abduction, including when the arm is in adducted position. Beyond 15 degrees the deltoid muscle becomes increasingly more effective at abducting the arm and becomes the main propagator of this action.

Trigger Points
Trigger points in the Supraspinatus are most frequently caused by activities that require loading of the arm, especially when the arm is hanging down to the side.
There are 3 trigger point in the Suprapinatus muscle all refure pain to the Deltoid muscle and down the arm.