Subacromial Bursitis

By Ben Benjamin, PhD

Subacromial Bursitis

By Ben Benjamin, PhD

Question: The bursa that protects the rotator cuff tendons of the shoulder is underneath which bone?

Answer: The acromion.

Question: How does the subacromial bursa function?

Answer: This fluid-filled sac acts as a cushioning device, preventing the rotator cuff tendons from running harshly over the bones. It changes shape and molds to the needs of the joint.

Question: Which motion is most limited and painful in cases of acute bursitis of the shoulder?

Answer: Passive abduction. In cases of acute bursitis (swelling of the bursa), passively abducting the arm - performed by the therapist - is very painful because the head of the humerus is compressing a swollen bursa against the glenohumeral joint and the underside of the acromion. The bursa is generally the size of a small plum, but when inflamed it can be as big as an orange. When acute bursitis is present in the shoulder, it is impossible to lift the arm out to the side (abduction) without extreme pain.

Question: Is massage therapy a useful treatment in cases of bursitis of the shoulder?

Answer: No. Inflammation of a bursa is not helped by direct massage. Directly massaging an inflamed bursa will cause more pain.

Question: How many types of bursitis of the shoulder are there?

Answer: Two. Acute bursitis is very painful and generally lasts six to eight weeks. Chronic bursitis produces much milder pain because the bursa is only slightly swollen, but it may last for many years unless treated by injection therapy.