Abdominal aortic aneurysm (AAA) is defined as which of the following?

• A. Local dilation of the aorta due to weakening of the walls
• B. Inflammation of the venous system
• C. Dilation of the pulmonary artery
• D. Aneurysm of the renal artery

Answer: (A)

An aneurysm is a localized dilation of an artery due to weakening of the vessel wall, and when this occurs in the abdominal portion of the aorta it is called an abdominal aortic aneurysm. This definition fits because the condition describes a specific segment of the aorta that has bulged outward from wall weakening, rather than a general enlargement of a vessel or a non-arterial process. The other options point to different problems: inflammation of veins is a venous condition, dilation of the pulmonary artery is a pulmonary artery aneurysm, and aneurysm of the renal artery refers to a renal artery aneurysm, none of which describe the abdominal aorta.