Impingement syndrome occurs when there is inflammation and injury of the rotator cuff tendons and the bursa that surrounds these tendons. There is a difference between tendonitis and bursitis, but there is a combination of these problems in most cases of impingement syndrome.1
The shoulder is a complex joint where several bones, muscles, and ligaments connect the upper extremity to the chest. Impingement syndrome occurs when there is inflammation between the top of the humerus (arm bone) and the acromion (tip of the shoulder blade). Between these bones are the tendons of the rotator cuff, and the bursa that protects these tendons. Normally, these tendons slide effortlessly within this space—called the subacromial space.
Impingement syndrome is a descriptive term for the pinching of the tendons of the rotator cuff between the bones causing injury . In many individuals with this problem, BONE SPURS or the shape of their bones is such that they have less space than others.
Often there is an initial injury that sets off the process of inflammation. After that, the problem can be self-exacerbating. Inflammation causes a thickening of the tendons and bursa. The thickening then takes up more space, and therefore the tendons and bursa become are pinched even more. This causes more inflammation, and more thickening of the tendons and bursa, and so on. If the process continues it can progress to tearing of the tendon.
source: VeryWellHealth.com
