Circumflex scapular aery is a branch of
**Core Concept**
The circumflex scapular artery is a branch of the subscapular artery, which is a major artery supplying the scapular region. The subscapular artery is a branch of the axillary artery, which in turn is a continuation of the brachiocephalic trunk. This artery is responsible for supplying blood to the scapular muscles and the scapula.
**Why the Correct Answer is Right**
The circumflex scapular artery arises from the subscapular artery, which is a terminal branch of the axillary artery. The subscapular artery then divides into the circumflex scapular artery and the thoracodorsal artery. The circumflex scapular artery supplies the scapular muscles and the scapula, playing a crucial role in the blood supply of this region. The subscapular artery also contributes to the blood supply of the serratus anterior muscle and the latissimus dorsi muscle.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the circumflex scapular artery does not arise from the deep artery of the arm. The deep artery of the arm is a branch of the brachial artery, which is a continuation of the axillary artery, but it does not give rise to the circumflex scapular artery.
* **Option B:** This option is incorrect because the circumflex scapular artery does not arise from the superior thoracic artery. The superior thoracic artery is a branch of the axillary artery, but it primarily supplies the upper part of the thoracic wall and does not give rise to the circumflex scapular artery.
* **Option C:** This option is incorrect because the circumflex scapular artery does not arise from the thoracoacromial artery. The thoracoacromial artery is a branch of the axillary artery, but it primarily supplies the muscles of the shoulder and does not give rise to the circumflex scapular artery.
* **Option D:** This option is incorrect because the circumflex scapular artery does not arise from the radial collateral artery. The radial collateral artery is a branch of the axillary artery, but it primarily supplies the muscles of the arm and does not give rise to the circumflex scapular artery.
**Clinical Pearl / High-Yield Fact**
The circumflex scapular artery is an important landmark for surgeons performing scapular surgery, as it is a key vessel to be preserved to maintain blood supply to the scapular muscles and the scapula.
**Correct Answer:** C. Subscapular artery.