Shoulder Impingement

Impingement is when soft tissues of muscles or tendons around a joint are squeezed between two or more hard/bony structures with activity/movement of that joint. It is a finding which most commonly affects the shoulder and hip due to the large range of motion of these ball joints. Impingement can be suspected by MRI when the soft tissues are squeezed which results in inflammation of the tendon (called tendinosis or tendiopathy). However impingement is best detected by a physical exam where the limb is moved either actively or passively. For example shoulder impingement can be identified by having difficulty raising an arm over the head.