True about internal thoracic artery is-
**Core Concept**
The internal thoracic artery is a vital vessel in the anterior chest wall, providing blood supply to the sternum, anterior chest wall, and the anterior surfaces of the 1st to 6th ribs. It is a branch of the subclavian artery and plays a crucial role in coronary artery bypass grafting (CABG) procedures.
**Why the Correct Answer is Right**
The internal thoracic artery is harvested for use as an arterial graft in CABG to bypass occluded coronary arteries. This is because it has a diameter similar to that of the coronary arteries and has a low risk of atherosclerosis, making it an ideal graft material. The internal thoracic artery is harvested along with the accompanying vein, which is used as a conduit to anastomose with the coronary artery.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the internal thoracic artery does not typically give off a significant branch to the diaphragm.
**Option B:** This option is incorrect because the internal thoracic artery is not primarily responsible for supplying blood to the posterior chest wall.
**Option C:** This option is incorrect because the internal thoracic artery is not typically used as a graft for peripheral artery disease.
**Clinical Pearl / High-Yield Fact**
It is essential to note that the internal thoracic artery is a bilateral vessel, and harvesting both arteries can lead to complications such as mediastinitis and sternal instability. Therefore, the decision to harvest one or both internal thoracic arteries should be made on a case-by-case basis.
**Correct Answer: C. It is used as arterial graft in CABG.**