COMLEX USA 2025 – 400 Free Practice Questions to Pass the Exam

The subscapularis muscle is primarily responsible for internal rotation of the shoulder joint. This muscle is located on the anterior surface of the scapula and plays a vital role in stabilizing the shoulder during arm movements. Its position allows it to produce a powerful internal rotation when the arm is raised or rotated.

In contrast, the other muscles listed function differently. The supraspinatus primarily initiates shoulder abduction. The infraspinatus and teres minor are key players in shoulder external rotation. Understanding the specific roles of these muscles highlights the unique contributions of the subscapularis in internal rotation and overall shoulder joint stability.