Question
Which of the following muscles is not included in the rotator cuff?
| A. | Supraspinatus |
| B. |
Infraspinatus |
| C. |
Teres major |
| D. |
Teres minor |
Show Answer
|
Correct Answer � C Explanation |
 |
The rotator cuff is a group of four muscles that stabilize the shoulder joint and provide dynamic movement. These muscles are:
- Supraspinatus: Initiates arm abduction.
- Infraspinatus: Performs external rotation of the arm.
- Teres minor: Assists with external rotation.
- Subscapularis: Performs internal rotation.
Why Teres Major is Not Included:
- Teres major is not part of the rotator cuff because its function differs. It primarily adducts and medially rotates the arm.
- The teres major inserts on the medial lip of the bicipital groove of the humerus, while the rotator cuff muscles attach to the humeral head to stabilize the glenohumeral joint.
- Instead of stabilizing the shoulder, the teres major works synergistically with the latissimus dorsi to control shoulder movements.
Reason to Rule Out Incorrect Options:
- Supraspinatus (Option A): This is part of the rotator cuff, initiating arm abduction.
- Infraspinatus (Option B): Part of the rotator cuff, responsible for external rotation of the arm.
- Teres minor (Option D): Also part of the rotator cuff, assisting with external rotation and stabilizing the humeral head.