Aortic dissection involves injury to which layer of the aorta?

Aortic dissection involves injury to which layer of the aorta?

• A. Intima (inner-most layer)
• B. Media
• C. Adventitia
• D. Epicardium

Answer: (A)

Aortic dissection starts with a tear in the innermost lining, the intima. The intima is the barrier between the blood in the lumen and the wall of the aorta; when it is damaged, high-pressure blood can force its way into the medial layer, splitting the wall and creating a false lumen. The wall then dissects within the media, but the initiating injury is to the intima. The adventitia is the outer supportive layer, and the epicardium is not a layer of the aorta.

Aortic dissection starts with a tear in the innermost lining, the intima. The intima is the barrier between the blood in the lumen and the wall of the aorta; when it is damaged, high-pressure blood can force its way into the medial layer, splitting the wall and creating a false lumen. The wall then dissects within the media, but the initiating injury is to the intima. The adventitia is the outer supportive layer, and the epicardium is not a layer of the aorta.