Which rotator cuff muscle is primarily involved in internal rotation?

The subscapularis muscle is primarily responsible for internal rotation of the shoulder. It is one of the four rotator cuff muscles, and its location on the anterior surface of the scapula allows it to exert the necessary force to rotate the humerus inward towards the body. This action is crucial for various movements in sports and daily activities, such as throwing and reaching.

In contrast, the other rotator cuff muscles have different primary functions; for instance, the infraspinatus and teres minor are primarily involved in external rotation of the shoulder, while the supraspinatus assists with shoulder abduction. Understanding the specific roles of these muscles within the context of shoulder movements helps in developing appropriate treatment and rehabilitation strategies in sports massage and physiotherapy.