Muscle · Shoulders

Teres minor

Musculus teres minor

A narrow strap running from the outer edge of the shoulder blade up to the back of the arm bone, working alongside infraspinatus as the second external rotator. Small as it is, its line of pull is the most downward of the whole cuff, so it is a large part of what stops the head of the arm bone riding up under the bony roof as the arm lifts. It shares its nerve with the deltoid, which is why weakness in the two tends to show up together, and it is the one cuff muscle that is usually spared when the others tear.