Rotator Cuff Tendonitis & Subacromial Bursitis

(Shoulder Impingement)

Rotator cuff tendonitis is when the rotator cuff tendons are inflamed or injured.

The rotator cuff is composed of four muscles that work together to help stabilize and move the shoulder. The arrangement of the tendons and the other important structures around the shoulder can be seen in the drawing below on the left.  

The primary function of the rotator cuff is to hold the glenohumeral joint in place while the larger muscles around the shoulder move and provide power to the arm.  When the rotator cuff is injured or inflamed, the humerus (the ball part of the joint) tends to ride up in the socket to pinch and irritate the rotator cuff, acromion, and bursa.  This causes pain and further injury (as is seen in the diagram below on the right).


When the humerus rides up, it can bump into the acromion and the AC joint (which make up the bony “roof” of the shoulder). This can eventually cause a spur to form on the undersurface of these bones, which can cause more irritation and even tears in the rotator cuff tendons.


The goal of all treatments for impingement, tendonitis, or bursitis is to decrease pain and restore shoulder function. Generally this involves more conservative therapies initially, with progression to more invasive therapy if the pain continues.