## **Core Concept**
The **axillary nerve** is a branch of the posterior cord of the brachial plexus, primarily responsible for innervating the deltoid muscle and the teres minor muscle. The rotator cuff is a group of muscles and their tendons that surround the shoulder joint, keeping the head of the humerus firmly within the shallow socket of the shoulder.

## **Why the Correct Answer is Right**
The **teres minor muscle** is one of the rotator cuff muscles, and it is supplied by the **axillary nerve**, along with the deltoid muscle. The teres minor assists in adduction and lateral rotation of the arm. The axillary nerve wraps around the neck of the humerus, providing innervation to both the deltoid and teres minor muscles.

## **Why Each Wrong Option is Incorrect**
* **Option A: Supraspinatus** - This muscle is supplied by the **suprascapular nerve**, not the axillary nerve. It is involved in stabilizing the shoulder joint and assisting in abduction of the arm.
* **Option B: Infraspinatus** - This muscle is also supplied by the **suprascapular nerve**, not the axillary nerve. It helps in lateral rotation of the arm.
* **Option D: Subscapularis** - This muscle is supplied by the **upper and lower subscapular nerves**, not the axillary nerve. It aids in medial rotation and adduction of the arm.

## **Clinical Pearl / High-Yield Fact**
A useful clinical correlation to remember is that the **axillary nerve** can be injured in shoulder dislocations or fractures of the humerus, leading to weakness of the deltoid and teres minor muscles, and resulting in a loss of shoulder abduction and lateral rotation.

## **Correct Answer: C. Teres minor**