Infraspinatus muscle

Hello again! This is Matt from Kenhub, and in this tutorial, we will discuss the origin, insertion, anatomy, and function of the infraspinatus.

In the human body, the rotator cuff is a functional, anatomical unit located in the upper extremity. It consists of the following muscles: the supraspinatus muscle, the infraspinatus muscle, teres minor muscle, and subscapularis muscle.

As mentioned, in this tutorial, we will focus on the infraspinatus muscle. This muscle originates in the infraspinatus fossa of the shoulder blade or scapula and inserts on the greater tubercle of the humerus.

The main function of the rotator cuff is to stabilize and center the humeral head in the joint socket, called the glenoid cavity. In addition, the muscles tighten the joint capsule preventing a pinch during shoulder movements.

Certainly, the rotator cuff, as the name suggests, plays a major role in the internal and external rotation of the upper arm in the shoulder joint.

All the muscles in the rotator cuff fulfill different individual functions. The function of the infraspinatus muscle is to be a strong external rotator and, additionally, to assist in both abduction and adduction.