Rotator cuff muscles anatomy

The rotator cuff muscles are a group of four muscles. For memorizing the muscles name we can retain the sentence “Rotator cuff SITS on the shoulder”. SITS means-

These are the four muscles which collectively called rotator cuff muscle.

Supraspinatus

Origin

The supraspinatus muscle originates from the supraspinatus fossa. A shallow depression in the body of the scapula above the spine.

Insertion

It is inserted into the greater tubercle of the humerus.

Nerve supply

The nerve supply of the supraspinatus muscle is Suprascapular nerve, C5 & C6, the superior trunk of the brachial plexus.

Blood supply

The blood supply is the Suprascapular artery.

Action

Extend the arm from 0 degrees to 15 degrees, when it is the main active muscle. It helps the deltoid muscle to abduct to 90 degrees in this range.

Function

The main function of supraspinatus muscle is stabilization. The action related to the supraspinatus muscle is the abduction of the humerus, which may have a weak effect on the lateral rotation of the humerus. The supraspinatus muscle, the most frequently torn rotator cuff muscle, has been the subject of extensive research.

Test of Supraspinatus

The assessment of this muscle is carried out by the Jobe’s test or commonly referred to as the “empty can” test. It’s through with a 90 degrees abduction and internal rotation (thumb pointing to the floor) of the arm while pressing down on the arm. If it is painful or weak, it is positive.

Clinical aspects

Among the four muscles of the rotator cuff, the supraspinatus muscle is the most commonly injured because it receives the greatest strength. Aging can also cause shoulder problems due to inactivity, natural atrophy of muscles and ligaments, and lifelong listening to Taio Cruz.

And Statistics show that Supraspinatus tendinitis (painful arc syndrome) is the very common disease. It is the most common inflammatory problem encountered around the shoulder joint as well as supraspinatus muscle. Typically it is seen in people aged 25-60.

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Rotator Cuff Muscles Anatomy With The Details Of Rotator Cuff