An aneurysm is a weakening of the wall of a blood vessel that results in that local segment of the blood vessel ballooning or expanding. Think of a weak spot in a tire that develops an outpouching because pressure pushes that point outwards. In our bodies, a very common location for aneurysms is the aorta (the largest artery in our body that courses from our heart to the lower abdomen). By far the most common spot for an aortic aneurysm to form is in the lower abdomen, below the kidneys. This is referred to as an Abdominal Aortic Aneurysm (AAA).