The shoulder is a complex structure which is highly mobile through proper coordination of multiple joints, tendons, muscles, ligamentous structures. A bursa is a small fluid filled sac that is found in the shoulder and around other joints in the body. It functions as a cushion or padding between bones and soft tissues. These soft tissue and bony structures can be injured or deteriorate with time and this can result in developing shoulder pain at rest or with use.
The tendons that are most commonly injured or develop wear-and-tear are the four rotator cuff tendons and one of the biceps tendons. Tendons are strong fibers that form a cord and connect muscles to bones. When the tendons become inflamed or frayed they cause pain and we refer to this as tendinitis. Tearing of these cords off of their bony attachments results in pain and/or lack of motion at the shoulder. Long standing tendon tears can result in a less stable joint or migration out of alignment with the socket.
The bursa sac at the top of the shoulder is called the subacromial bursa. It is responsible for providing a cushion between the muscle and overlying bone to help reduce friction with movement of the shoulder. When this sac becomes inflammed or swollen, it causes pain with use of the shoulder. This condition is called subacromial bursitis.
The tendons and bursa that pass over the top of the shoulder between the overlying bone (acromion, part of the scapula) and the head of the arm bone (humerus) can become inflamed with repetitive “pinching” when lifting of the arm away from the body. This is referred to as impingement. X-rays may be performed to rule out arthritis or calcific tendinitis (calcium deposits in the tendon) as a cause of the pain.
Treatment of rotator cuff tendinitis or bursitis consists of therapy, oral anti-inflammatory medications, injections, and modification of activities. If conservative treatments fail, selected cases may be candidates for shoulder arthroscopic surgery.