Final answer:
The infraspinatus and teres minor are important muscles involved in shoulder external rotation and are part of the rotator cuff. These muscles enable lateral rotation of the arm and play a substantial role in activities like throwing. Injury to the rotator cuff from repetitive motions is common among athletes like baseball pitchers.
Step-by-step explanation:
The role of the infraspinatus and teres minor muscles in shoulder external rotation is crucial for the stability and mobility of the shoulder joint. Both of these muscles are part of the rotator cuff, a group of muscles and tendons that provide support for the shoulder joint. The infraspinatus is located below the scapular spine and is responsible for the lateral rotation of the arm at the shoulder joint. The teres minor, despite being smaller, also assists in this external rotation.
During activities like throwing a baseball, these muscles act in coordination to rotate the humerus and stabilize the shoulder. However, repetitive motion can cause injury. This is evident in baseball pitchers who often suffer from rotator cuff issues, including pinching, inflammation, or even tearing of the tendons away from the bone.
The shoulder muscles, including the infraspinatus and teres minor, originate on the scapula and are integral in performing diverse movements. Superior and inferior rotations of the scapula, facilitated by these muscles, are necessary for the full range of motion, especially during upper limb abduction when carrying heavy loads.