Final answer:
Shoulder external rotation is the movement of the arm at the shoulder joint that moves the anterior surface of the limb away from the midline of the body. This movement is performed by the infraspinatus and teres minor muscles, which are part of the rotator cuff. Inflammation or tears of the rotator cuff can lead to shoulder pain and limited range of motion.
Step-by-step explanation:
The shoulder external rotation refers to the movement of the arm at the shoulder joint that moves the anterior surface of the limb away from the midline of the body. This movement is performed by two muscles, the infraspinatus and teres minor, which are part of the rotator cuff. The rotator cuff is a group of tendons that connect the scapula to the humerus and is responsible for stabilizing and rotating the shoulder joint.
During shoulder external rotation, the infraspinatus and teres minor contract to rotate the humerus outward. This movement is important for activities that require reaching behind the back or throwing motions, such as pitching a baseball. When the rotator cuff becomes inflamed or torn, it can lead to shoulder pain and limited range of motion, often requiring surgical intervention.