All are muscles of rotator cuff EXCEPT:
**Question:** All are muscles of rotator cuff EXCEPT:
A. Supraspinatus
B. Subscapularis
C. Teres Minor
D. Teres Major
**Core Concept:**
The rotator cuff is a group of four muscles that surround and stabilize the humerus (upper arm bone) within the shoulder joint. These muscles are the supraspinatus, subscapularis, teres minor, and teres major. While all four muscles are part of the rotator cuff, one of them is not present in the given options.
**Why the Correct Answer is Right:**
The correct answer, **D. Teres Major**, is absent from the rotator cuff because it is a separate muscle group that does not specifically contribute to the stabilization of the humerus within the shoulder joint. Instead, it plays a role in external rotation of the humerus at the glenohumeral joint.
**Why Each Wrong Option is Incorrect:**
A. **Supraspinatus**: This muscle is indeed a part of the rotator cuff, playing a crucial role in both lifting and stabilizing the humerus.
B. **Subscapularis**: Another essential muscle of the rotator cuff, it assists in both abduction and internal rotation of the humerus.
C. **Teres Minor**: Although less significant in stabilizing the humerus, it is still a part of the rotator cuff, contributing to external rotation.
**Clinical Pearl:**
Understanding the distinct roles of these muscles is crucial for understanding the complex biomechanics of the shoulder joint and preventing shoulder-related injuries. A thorough knowledge of the anatomy, biomechanics, and functional roles of the muscles of the rotator cuff is essential for diagnosing and treating shoulder disorders accurately.