The subacromial bursa is located underneath the acromiom, to prevent compression of soft tissue against the bone. This fluid-filled sac has two major sections and most of it is inaccessible. The more distal portion is the subdeltoid bursa. When the arm is fully abducted, the bursa moves up under the acromiom process. The bursa can be agitated by repetitive compression of the humerus into the acromiom due to a tight upper trapezius, middle deltoid, and supraspinatus muscle. An indicator of bursitis is when shoulder pain begins shortly after initiating shoulder abduction, and continues to about 135˚. This is called a painful arc, which happens because the irritated bursa is compressed as the client abducts the shoulder. After 135˚ of abduction, the irritated tissue moves proximally under the acromiom process and is no longer compressed. The pain is described as being deep within the shoulder joint.
There can also be an inflammation to the bursa resulting from autoimmune disease such as rheumatoid arthritis, infection, gout, calcific deposits, or other systemic disorders. Remember, if in doubt, always refer out!
- To eliminate bursitis, the most important muscles to work are the anterior shoulder muscles that contribute to shoulder impingement, and the upper trapezius, middle deltoid, and supraspinatus muscles which may be causing compression on the bursa.
- This will release the tension on the shoulder joint and usually alleviate the symptoms of bursitis.
- Caution! The actual inflammatory site of bursitis is never worked.