**Question:** Most common muscle damaged in rotator cuff is

A. Supraspinatus
B. Infraspinatus
C. Teres Minor
D. Subscapularis

**Core Concept:**
The rotator cuff is a group of four muscles and their tendons that surround and stabilize the humeral head within the glenohumeral joint. These muscles are crucial for maintaining proper joint function and preventing shoulder instability.

**Why the Correct Answer is Right:**
The correct answer, **A. Supraspinatus**, is the most commonly affected muscle in the rotator cuff due to its location at the top of the humeral head and its role in stabilizing the joint during abduction and external rotation.

**Why Each Wrong Option is Incorrect:**

**B. Infraspinatus:** This muscle is situated at the posterior aspect of the humeral head, making it less vulnerable to injury compared to the supraspinatus.

**C. Teres Minor:** Although part of the rotator cuff, this muscle is relatively smaller and less involved in joint stability compared to the other muscles.

**D. Subscapularis:** This muscle is located in the anterior aspect of the glenohumeral joint, placing it less at risk for injury compared to the supraspinatus.

**Clinical Pearl / High-Yield Fact:**
Understanding the anatomy and function of the rotator cuff muscles is crucial for diagnosing and treating shoulder injuries. A comprehensive knowledge of these muscles' roles in shoulder stability contributes to accurate clinical assessment and appropriate treatment strategies.

**Correct Answer:** **A. Supraspinatus** is the most common muscle affected in rotator cuff injuries due to its position at the top of the humeral head, playing a significant role in abduction and external rotation.