An abdominal aortic aneurysm is an abnormal swelling in the aorta. It can be fatal.
The aorta is the body's largest artery. It carries oxygen-rich blood from the heart to smaller arteries in the body.
An abdominal aneurysm occurs in the abdominal aorta. This is the part of the aorta between the bottom of the chest and the pelvis.
An abdominal aortic aneurysm usually causes a balloon-like swelling. The wall of the aorta bulges out.
Normally, the aorta is about one inch (2.5 centimeters) in diameter. The size increases very gradually as people age. If the abdominal aorta becomes larger than 3 centimeters, this is called an abdominal aortic aneurysm.
Most aortic aneurysms are related to atherosclerosis. In atherosclerosis, fatty deposits build up along the inside walls of blood vessels.