Condition · Shoulders

Shoulder impingement

There is a narrow gap between the top of your arm bone and the bony roof above it, and the cuff tendons run through it. Impingement is what it's called when that gap gets squeezed while you lift — but the gap is not usually the problem. It closes because the shoulder blade isn't rotating upward to make room, or because the cuff isn't holding the head of the arm bone down while the deltoid pulls it up. That's why it hurts in an arc partway up and then eases at the top, and why stretching the sore spot rarely fixes it: the tissue is the victim, not the cause.