[Anatomy and etiology of aortic aneurysms].

The term "aortic aneurysm" applies to numerous conditions with extremely varied anatomical and aetiological features, which consist of more or less complete and localized destruction of the aortic wall components resulting in a sacciform or fusiform distension induced by blood pressure, with loss of parallelism between the sides of the aorta. The most frequent aneurysms, leading to numerous cardiovascular operations, are encountered mainly in middle-aged men. These aneurysms complicate the infra-renal terminal atherosclerosis of smokers or the parietal elastic dystrophy of the ascending aorta, where a few subjects in their twenties with Marfan's disease join the older men, and which clinically presents as severe aortic incompetence. The aneurysm of syphilis and its destructive effect on thoracic structures is a thing of the past with a purely historical interest. Dissecting aneurysms--which should be called incomplete internal aortic disease with delamination of the media--remains a fearsome disease in subjects over 50, despite advances in surgery. Rare types of aneurysm (traumatic, infectious, or local accentuation of megadolichoarteries, aortitis or connective tissue dysgenesis) complete the list.