Aortic aneurysm and dissection of the aorta

Abstract

An aneurysm is an abnormal dilatation of a blood vessel. Cross-sectional dilatation is invariably accompanied by elongation of the vessel so that tortuosity is inevitable. The median diameter of the aorta is greater in men than women and increases progressively above 40 years of age in both sexes. Dilatation of part of the aorta relative to adjacent normal aorta can easily be seen to be aneurysmal but when the whole aorta dilates the diagnosis may be less obvious. Current convention classifies an infra-renal aorta as aneurysmal if the anteroposterior external diameter is 3.0 cm or greater.