Final answer:
To assess internal rotation of the shoulder, a physical therapist would evaluate the movement of the arm's anterior surface toward the body's midline and look into the functioning of the glenohumeral joint and muscles forming the rotator cuff.
Step-by-step explanation:
To assess internal rotation of the shoulder, a physical therapist (PT) would evaluate the movement whereby the anterior surface of the arm moves toward the midline of the body. This evaluates the functionality of the glenohumeral joint, a multiaxial ball-and-socket joint allowing for a range of motions including medial (internal) rotation. The therapist would look for normal function and signs of injury by asking the patient to perform specific movements like abduction, adduction, and circumduction of the arm. Muscles and tendons, particularly those forming the rotator cuff (including the subscapularis, supraspinatus, infraspinatus, and teres minor), are crucial for these movements and are assessed for injury or inflammation, as in the case of athletes like baseball pitchers who frequently undergo rotator cuff surgeries due to repetitive motion injuries.