Which of the following aery is a branch of the first pa of axillary aery?
## **Core Concept**
The axillary artery is a continuation of the subclavian artery and is divided into three parts based on its relation to the pectoralis minor muscle. The first part is proximal to the pectoralis minor muscle and gives off one branch.
## **Why the Correct Answer is Right**
The first part of the axillary artery gives off the **superior thoracic artery**. This artery arises from the axillary artery proximal to the pectoralis minor muscle and supplies the first and second intercostal spaces, specifically the serratus anterior and the upper part of the intercostal spaces.
## **Why Each Wrong Option is Incorrect**
- **Option A:** The **thoraco-acromial artery** and **lateral thoracic artery** are branches of the second part of the axillary artery, which is behind the pectoralis minor muscle. Therefore, option A is incorrect.
- **Option B:** The **subscapular artery** is a branch of the third part of the axillary artery, which is distal to the pectoralis minor muscle. Hence, option B is incorrect.
- **Option D:** The **inferior thyroid artery** is not a branch of the axillary artery; it usually arises from the thyrocervical trunk, which in turn arises from the subclavian artery. So, option D is incorrect.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the axillary artery's branches can be recalled based on their parts and the structures they supply. The superior thoracic artery is crucial for supplying blood to the upper intercostal spaces.
## **Correct Answer:** . **superior thoracic artery**