An aortic aneurysm is a bulge that occurs in the wall of the major blood vessel (aorta) that carries blood from the heart to the body. Aortic aneurysms can occur anywhere in the aorta and may be tube-shaped (fusiform) or round (saccular).

Aortic aneurysms include:

• Abdominal aortic aneurysm occurs along the part of the aorta that passes through the abdomen.
• Thoracic aortic aneurysm occurs along the part of the aorta that passes through the chest cavity.

Some people may have both types of aortic aneurysms.

Having an aortic aneurysm increases the risk of developing a tear in the inner layer of the wall of the aorta (aortic dissection).