The normal diameter of the abdominal aorta is about one inch. Most aortic aneurysms occur in the abdominal aorta, the main cause being arteriosclerosis. This is a condition in which fatty deposits are laid down in the walls of arteries, which are less elastic and weaker as a result. Major risk factors for arteriosclerosis are smoking and high blood pressure, although it also probably runs in families. This is a very serious condition, in which the inner wall of the aorta develops a tear and then rips off inside the aorta due to the pressure of the blood flowing over it.
Many people can have an aortic aneurysm for years before any symptoms develop.
When they do become evident, symptoms vary according to the type and location of the aneurysm. This causes excruciating pain in the abdomen and back. There is severe internal bleeding which is often fatal. The symptoms of a thoracic aortic aneurysm often do not occur until the aneurysm is quite large. The pain may then go down into the abdomen and lower back.