## **Core Concept**
Aortic dissection occurs when there is a tear in the intimal layer of the aorta, allowing blood to enter the aortic wall and create a false lumen. This condition can lead to severe complications, including aortic rupture or organ malperfusion.

## **Why the Correct Answer is Right**
The intima is the innermost layer of the aorta, and a tear in this layer allows blood to enter the media, creating a false lumen. This is the initiating event in aortic dissection. The intimal tear is typically located in the ascending aorta or the descending aorta.

## **Why Each Wrong Option is Incorrect**
* **Option A:** The media is the middle layer of the aorta, but blood enters the dissection plane from the intima, not directly into the media.
* **Option B:** The adventitia is the outermost layer of the aorta, but it is not where blood initially enters in aortic dissection.
* **Option D:** While the vasa vasorum supplies blood to the aortic wall, it is not directly related to the entry point of blood in aortic dissection.

## **Clinical Pearl / High-Yield Fact**
A classic clinical correlation is that hypertension is both a risk factor for and a common finding in aortic dissection. Controlling blood pressure is crucial in managing acute aortic dissection.

## **Correct Answer:** . Intima