Most common cause of aoic aneurysm is -

Aneurysms are congenital or acquired dilations of blood vessels or the hea . "True" aneurysms involve all three layers of the aery (intima, media, and adventitia) or the attenuated wall of the hea; these include atherosclerotic and congenital vascular aneurysms, as well as ventricular aneurysms resulting from transmural myocardial infarctions. By comparison, a false aneurysm (pseudoaneurysm) results when a wall defect leads to the formation of an extravascular hematoma that communicates with the intravascular space ("pulsating hematoma"). Examples are ventricular ruptures contained by pericardial adhesions and leaks at the junction of a vascular graft with a natural aery. The two most impoant causes of aoic aneurysms are atherosclerosis and hypeension. Atherosclerosis is the more dominant factor in abdominal aoic aneurysms, while hypeension is associated with ascending aoic aneurysms. (Robbins basic pathology,9th edition.pg no.345)