Glossary of Terms

Aneurysm / Aortic Aneurysm
Aneurysm is the expansion of an artery that is caused when the wall of the artery is weakened because of inherited disease, such as Marfan sydrome, or atherosclerosis (build up of fatty deposits called plaque).

The elastic tissue that forms the artery wall allows the vessel to expand and contract. When the tissue is stretched at any point, the weakened section of the artery pouches out (sac) and becomes swollen from internal pressure, and is in danger of rupturing. If the blood-filled sac ruptures, a serious, often fatal hemorrhage may follow.

The most common artery that is affected by aneurysms is the aorta, the large artery leading from the heart. Aneurysms, even small ones, can prove fatal when they occur in the heart, brain, or other vital organ. When aneurysms become greatly enlarged, pressure is exerted and crowds the area in which it occurs, such as the abdominal or chest cavity. Aneurysms may be painful, or produce difficulty in breathing (dyspnea), by pressing against the air passages, or cause swelling.