**Question:** All are muscles of rotator cuff EXCEPT:

A. Supraspinatus
B. Infraspinatus
C. Teres minor
D. None of the above

**Correct Answer:** D. None of the above

**Core Concept:** Rotator cuff muscles

The rotator cuff is a group of four muscles that surround and stabilize the humeral head in the glenohumeral joint, allowing for a wide range of motion and preventing dislocation. The specific muscles are:

1. **Supraspinatus:** This muscle originates from the spine of the scapula and inserts on the humeral head. It plays a crucial role in external rotation and abduction of the arm.
2. **Infraspinatus:** Similar to supraspinatus, it originates from the spine of the scapula and inserts onto the humeral head. Infraspinatus is involved in external rotation and abduction of the arm.
3. **Teres minor:** This muscle originates from the lateral lip of the glenoid fossa and inserts onto the humeral head. Teres minor contributes to internal rotation and abduction of the arm.

**Why the Correct Answer is Right:**

Since all the provided options (A, B, C) are indeed muscles of the rotator cuff, the correct answer is "D. None of the above". This is because none of the mentioned muscles (supraspinatus, infraspinatus, and teres minor) are NOT part of the rotator cuff muscles.

**Why Each Wrong Option is Incorrect:**

A. Supraspinatus and infraspinatus are part of the rotator cuff, but teres minor is not.
B. Infraspinatus and teres minor are part of the rotator cuff, but supraspinatus is not.
C. Teres minor is part of the rotator cuff, but supraspinatus and infraspinatus are not.

**Clinical Pearl:**

Understanding the anatomy and function of rotator cuff muscles is crucial for accurate diagnosis and treatment of shoulder pathologies. Physical examination and imaging studies, such as ultrasound or MRI, can help differentiate between muscle injuries and other shoulder disorders.

**Why Each Wrong Option is Incorrect:**

A. Teres minor is a separate muscle that contributes to internal rotation and abduction of the arm but is not part of the rotator cuff.
B. Infraspinatus and teres minor are part of the rotator cuff, but supraspinatus is not.
C. Teres minor is part of the rotator cuff, but supraspinatus and infraspinatus are not.

**Why the Correct Answer is Right:**

Teres minor is a separate muscle and not part of the rotator cuff. The correct answer is "None of the above" because all provided options are incorrect.