Teres Minor Muscle: Definition, Function & Innervation

Instructor: Dan Washmuth

Dan has taught college Nutrition, Anatomy, Physiology, and Sports Nutrition courses and has a master's degree in Dietetics & Nutrition.

The teres minor is a very small muscle with a very big and important role. Read this lesson to learn all about the teres minor, including its definition, function, and innervation.

Small Muscle, Big Importance

Have you pulled a door open recently? Or have you recently raised your arm out to the side or over your head without your shoulder becoming dislocated? If you answered 'Yes' to both of these questions, then you should thank your teres minor muscle.

What is the Teres Minor?

The teres minor is a small, thin muscle that is located in the shoulder joint, in the area of the armpit. In Latin, teres means 'rounded', which is a reference to this muscle's rounded muscle belly. Additionally, this muscle is classified as a deep muscle since there are several muscles and tendons that lie on top of the teres minor.


The teres minor is a small, thin muscle that is located in the armpit region of the shoulder joint.
teres minor


Function of the Teres Minor

The teres minor is one of four muscles that make up the rotator cuff. The rotator cuff is a collection of small muscles in the shoulder whose main function is to maintain the stability of the shoulder joint. The shoulder joint is formed by the head of the humerus (long bone of the upper arm) fitting into the scapula (shoulder blade). The rotator cuff muscles, which include the teres minor, function to make sure that these bones stay in their correct locations while the shoulder joint moves around.

In addition to maintaining shoulder stability, the teres minor also functions to laterally rotate the humerus. Lateral rotation of the humerus involves turning the upper arm outward toward the side of the body, such as when you rotate your arm when pulling a door open.


One of the functions of the teres minor is to maintain stability of the shoulder joint by helping to keep the head of the humerus in its correct location against the scapula.
shoulder joint


Innervation of the Teres Minor

Innervation refers to a muscle receiving electrical signals from the brain through a nerve or nerves. The nerve that innervates the teres minor is the axillary nerve, which is a nerve that consists of nerve fibers from the fifth and sixth cervical (neck) nerves (C5, C6). Axillary is a term that refers to the armpit region of the body. Therefore, the axillary nerve innervates many of the muscles located near the armpit.

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