Final answer:
The correct answer to the student's question is C) teres major, as it is not a part of the rotator cuff. The rotator cuff consists of the supraspinatus, infraspinatus, teres minor, and subscapularis muscles.
Step-by-step explanation:
The student asked which of the following muscles is not part of the rotator cuff: A) supraspinatus B) teres minor C) teres major D) subscapularis. The rotator cuff includes the following four muscles: supraspinatus, infraspinatus, teres minor, and subscapularis. These muscles arise from the scapula and attach to the greater or lesser tubercles of the humerus, and their tendons form a cuff around the shoulder joint, which is essential for stabilizing the joint and allowing a wide range of movements.
Among the provided options, the teres major is not a part of the rotator cuff. The four true rotator cuff muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) serve as dynamic ligaments, providing structural support to the glenohumeral joint. The rotator cuff is crucial for the mobility and stability of the shoulder joint and is often associated with injuries in activities that require repetitive overhead motions, such as baseball pitching.