Shoulder impingement syndrome
Shoulder impingement syndrome refers to compression of the supraspinatus tendon and subacromial bursa between the coracoacromial arch and humeral head. It can be secondary to multiple causes, including subacromial spurs, osteoarthritis of the acromioclavicular joint, and an os acromiale, among others. Impingement is thought to precipitate degeneration of the rotator cuff tendons, leading to rotator cuff tears.