The subacromial bursa is a fluid field sack, designed to reduce friction between the rotator cuff tendons and the bone above. Bursae can be found in various locations around the body to reduce friction and tendon damage.
The subacromial bursa is probably the most pain sensitive structure in the shoulder. It is located between the top of the rotator cuff tendons and the bony roof of the shoulder (the acromion).
Subacromial bursitis caused by shoulder impingement, where the humeral head is pushed up into the acromion during arm elevation. If this happens frequently, damage can occur to the rotator cuff tendon and cause bursitis.
Bursitis is inflammation of the bursal sack caused by impingement. When this happens, the cells lining the bursa become irritated and produce more fluid into the bursa. This stretches the walls of the bursa, causing pain.
Repeated injuries or repeated incidents of acute bursitis can cause chronic shoulder bursitis. It’s the most common type of shoulder bursitis. You may have periods without symptoms and then have a return of symptoms. Sometimes that might last several months. Bursitis might cause pain this week, ease next week, only to return the following week, depending on the amount of arm raising is performed.
Sometimes shoulder bursitis can be seen with diagnostic ultrasound. This will show engorgement of the bursa with fluid. Bursitis is a condition which can come and go with physical stress. Often a patient may have bursitis shown on ultrasound, but one or two weeks later, it may not be present, only to return a month after that.
Bursitis is an inflammatory issue. Inflammatory pain is characterised by resting pain, such as difficulty getting to sleep or waking up in pain during sleep.
Sometimes patients are referred for an ultrasound-guided Cortizone injection into the bursa to decrease inflammation. This is sometimes successful. However, this does not solve the problem. To have a long-term solution to bursitis, it’s critical to control shoulder impingement.
At Melbourne Shoulder Therapy, we will assess the factors causing the impingement and deal with them. This will prevent further episodes of bursitis.