The teres muscle, also known as the teres major muscle, is a small muscle located in the upper arm near the shoulder joint. It is responsible for rotating the arm inward and pulling it towards the body. However, it is often confused with the larger muscle, the latissimus dorsi, which covers most of the back and shoulder area. Some possible synonyms for the teres muscle include teres major, teres minor, and axillary muscle. Other terms that may be used to refer to this muscle include the shoulder blade muscle, the upper arm muscle, and the rotator cuff muscle. Regardless of what it is called, the teres muscle plays an important role in arm movement and overall shoulder stability.