Subacromial bursitis is a conition caused by inflammation of the bursa that separates the superior surface of the supraspinatus tendon (one of the four tendons of the rotator cuff) from the overlying coraco-acromial ligament, acromion, coracoid ( the acromial arch) and from the deep surface of the deltoid muscle . The function of a healthy subcromial bursa is to facilitate the motion of the supraspinatus tendon of the rotator cuff in activities such as overhead work.