Hello again, everyone! It’s Matt from Kenhub, and in this tutorial, we will discuss the origin, insertion, innervation, and action of the teres minor muscle.
Along with the supraspinatus muscle, infraspinatus muscle, and subscapularis muscle, the teres minor makes up the rotator cuff, which is a functional, anatomical unit in the upper arm. On this image, we can see the teres minor highlighted in green.
All the muscles of the rotator cuff originate from the scapula and insert in the humerus, but the teres minor muscle specifically originates from the lateral scapula border and inserts on the greater tubercle of the humerus.
In terms of innervation, the axillary nerve seen on this image, highlighted in green, will innervate the teres minor. The axillary nerve originates from the posterior cord of the brachial plexus at the level of your armpit.
The rotator cuff, as the name suggests, plays a major role in the internal and external rotation of the upper arm and the shoulder joint. Its main function is to stabilize the glenoid cavity and keep the humeral head centered in the joint socket. This joint is the most flexible in the human body, and this group of muscles tighten around the joint to prevent a pinch during shoulder movement.
The teres minor muscle’s function consists primarily of external rotation, partly retroversion and adduction as well. It works in conjunction with the infraspinatus muscle performing many of the same actions.
Because they share a first name, it’s easy to confuse the function and anatomy of the teres major and the teres minor.
One memory trigger is to think of the teres major as performing the same action of a major muscle (its big brother), the latissimus dorsi, and the teres minor as performing the same action of a minor muscle, the infraspinatus.