Muscle · Shoulders

Teres major

Musculus teres major

A thick strap from the bottom corner of the shoulder blade to the front of the upper arm bone, doing the same three jobs as the latissimus dorsi — pulling the arm down, in, and rotating it inward. Hence the old nickname, lat's little helper. Despite living in the middle of the rotator cuff's neighbourhood it is not a cuff muscle: it does not attach to the joint capsule and does nothing to centre the head of the humerus. With the latissimus it forms the fold you can pinch at the back of the armpit.