What Does the Teres Minor Muscle Do

As a rotator cuff muscle, the teres minor stabilizes the ball-and-socket glenohumeral joint by helping hold the humeral head (ball) into the shallow glenoid cavity of the scapula (socket). The teres minor also laterally, or externally, rotate the arm at the shoulder joint.

Why is the teres minor important?

The teres minor muscle is important in maintaining shoulder stability in the presence of other rotator cuff dysfunction. External rotation of the glenohumeral joint is produced mainly by the infraspinatus and teres minor force couple. These two muscles are difficult to differentiate in regard to strength and function.

What does the teres major muscle do?

The teres major is a medial rotator and adductor of the humerus and assists the latissimus dorsi in drawing the previously raised humerus downwards and backwards (extension, but not hyperextension). It also helps stabilise the humeral head in the glenoid cavity.