what causes shoulder impingement
There are three main risk factors for developing shoulder impingement. First is anatomy. If you have a Type III or âhookedâ acromion, you are more predisposed to shoulder impingement. Secondly, weakness in your posterior cuff (infraspinatus/teres minor) can cause abnormal shoulder mechanics leading to impingement.
Whether it is throwing a baseball, hitting an overhead smash, swimming the butterfly, or simply painting a wall, repeated overhead motions can become very painful if your rotator cuff is not functioning properly. Shoulder impingement is one of the most common causes of pain in the shoulder. It results from the rotator cuff being pinched between the humerus and the scapula. The rotator cuff is made up of four muscles: the supraspinatus, the infraspinatus, the teres minor, and the subscapularis.
Bursitis (inflammation of a bursa) often occurs along with tendonitis and/or impingement syndrome. A bursa is a sac (containing a small amount of fluid) located between the tendon and bone that helps the moving parts of a joint glide smoothly. There is a bursa between the supraspinatus (a rotator cuff tendon) and acromion (roof of shoulder blade). Occasionally, calcium deposits or bone spurs may be present within the rotator cuff tendon(s) or the underside of the acromion. This can also cause impingement syndrome.