Question

What parts of rotator cuff do external rotation? innervation?

Answer 1

The infraspinatus and teres minor muscles of the rotator cuff are responsible for external rotation of the arm, with innervation provided by the suprascapular and axillary nerves, respectively.

Step-by-step explanation:

The parts of the rotator cuff that perform external rotation are the infraspinatus and teres minor muscles. These muscles are responsible for rotating the arm laterally away from the body. Innervation of these muscles is provided by the suprascapular nerve for the infraspinatus and the axillary nerve for the teres minor. The repetitive motion of bringing the arm overhead, as seen in activities such as pitching in baseball, can lead to inflammation or injury to the rotator cuff tendons.

The rotator cuff, comprising the infraspinatus and teres minor muscles, facilitates external rotation, moving the arm outward. Innervated by the suprascapular and axillary nerves, respectively, these muscles can be strained by repetitive overhead motions like baseball pitching, causing inflammation or injury to the tendons.

Answer 2

The infraspinatus and teres minor muscles of the rotator cuff are responsible for external rotation of the shoulder, innervated by the suprascapular and axillary nerves. These muscles are crucial in many athletic movements and are susceptible to repetitive motion injuries.

Step-by-step explanation:

The rotator cuff is a critical structure in the shoulder, providing both stability and movement to the shoulder joint. Out of the muscles that comprise the rotator cuff, the infraspinatus and teres minor muscles are primarily responsible for external (lateral) rotation of the shoulder. The supraspinatus helps with the initial part of the abduction before the deltoid takes over, while the subscapularis is involved in internal rotation.

The innervation for these muscles is as follows: the infraspinatus and teres minor muscles are innervated by the suprascapular nerve (C5-C6) and axillary nerve (C5-C6), respectively. The importance of the rotator cuff comes to light especially in athletes, such as baseball pitchers, who commonly suffer injuries to this area due to the repetitive, high-velocity motions required by their sport. These injuries can range from inflammation and pinching to tears, which might necessitate surgical intervention.

Understanding the anatomy and function of the rotator cuff, particularly the muscles involved in external rotation, is essential for diagnosing and treating shoulder-related issues, as well as for developing injury-prevention practices for athletes and individuals engaged in repeated overhead activities.