What are the three most common impingement syndromes?

1. Superior: supraspinatus tendon compressed between the humeral head and the acromion; often exacerbated by abduction
2. Posterior: infraspinatus compressed between the humeral head and the posterior superior glenoid; uncommon and typically seen in throwing sports, exacerbated by the ABER position
3. Anterior (subacromial): subscapularis tendon compressed between the humeral head and the coracoid process; often seen in large coracoid processes