Question

This is one of the rotator cuff muscles. It is a lateral rotator of the arm and is served by the supra scapular nerve. It inserts on the humerus, specifically on the posterior aspect of the greater tubercle. It originates on the infraspinous fossa of the scapula.

Answer 1

The infraspinatus muscle is a component of the rotator cuff muscles, inserting on the posterior aspect of the greater tubercle of the humerus and acting as a lateral rotator of the arm.

Step-by-step explanation:

The muscle described in the student's question is the infraspinatus, which is one of the four rotator cuff muscles. The infraspinatus originates on the infraspinous fossa of the scapula and inserts on the posterior aspect of the greater tubercle of the humerus. It functions as a lateral rotator of the arm and is innervated by the suprascapular nerve. The rotator cuff muscles, consisting of the supraspinatus, infraspinatus, teres minor, and subscapularis, play vital roles in stabilizing the shoulder joint by encircling the head of the humerus and fusing to the walls of the articular capsule, forming a thickening known as the musculotendinous cuff. They help maintain the head of the humerus within the glenoid cavity of the scapula, effectively acting as dynamic ligaments.