Which muscles are responsible for medial rotation at the shoulder?

The muscles responsible for medial rotation at the shoulder include the pectoralis major, teres major, and subscapularis.

The pectoralis major is a large muscle located in the chest that plays a significant role in various shoulder movements, including medial rotation. The teres major, while smaller, assists in the medial rotation of the humerus as well. The subscapularis, part of the rotator cuff, is particularly essential for this function as it is specifically designed to medially rotate the shoulder; it is located on the anterior aspect of the scapula and its contraction pulls the humeral head inward and forward.

Both the other options include muscles that contribute to shoulder movements, but they primarily serve functions other than medial rotation. Understanding the roles of these specific muscles helps clarify their contribution to shoulder biomechanics and highlights why the selected group is correct for this particular action.