Final answer:
Aortic dissection occurs when there is a tear in the inner layer of the aorta wall, allowing blood to enter the wall and separate its layers. The aorta is divided into the ascending aorta, aortic arch, and descending aorta and is the primary artery distributing blood from the heart to the rest of the body.
Step-by-step explanation:
The location of an aortic dissection in the vessel wall occurs in the layers of the aorta, which is the largest artery in the body. The aorta comprises the ascending aorta, the aortic arch, and the descending aorta, each with critical functions in blood distribution to the body's tissues. The ascending aorta originates at the aortic semilunar valve at the base of the aorta, preventing blood backflow into the left ventricle, and extends superiorly for about 5 cm before leading into the aortic arch. Aortic dissection often involves a tear in the inner layer of the aorta wall, allowing blood to enter the wall of the artery and split it apart.