An aneurysm is an enlarged and weakened section of an artery, a blood vessel that carries blood away from the heart. It is a serious health concern because as it increases in size it can rupture. Most aneurysms occur in the aorta, which is the largest artery in your body. The aorta runs from the heart through the chest and abdomen.
An aneurysm that occurs in your abdomen is called an abdominal aortic aneurysm. Abdominal aortic aneurysms are the most common type of aneurysm. Aortic aneurysms can generally be divided into simple aneurysms and complex aneurysms.