Most common cause of an Abdominal aneurysm is -
Abdominal aortic aneurysm

The most common aetiology for an abdominal aortic aneurysm is atherosclerosis.
Atherosclerosis causes arterial wall thinning through medial destruction secondary to a plaque that originates in the intima.

Besides abdominal aorta, atherosclerotic aneurysm also occurs in common iliac arteries, arch and descending part of the thoracic aorta.


The usual site of abdominal aortic aneurism is below the origin of the renal artery and above the bifurcation of the aorta.


Remember

Most common cause of an aortic aneurysm (overall) = Atherosclerosis.
Most common cause of ascending aortic aneurysm = Cystic medial necrosis.

Most common cause of descending aortic aneurysm = Atherosclerosis.


Most common cause of aneurysm of aortic arch = Atherosclerosis.


A syphilitic aneurysm affects = Ascending aorta.


Aneurysm of Takayasu arteritis affects = Aortic arch.


Most common cause of mycotic abdominal aneurysm = salmonella gastroenteritis.
Atherosclerosis
Trauma
Marfan's syndrome
Congenital