features of an aneurysm

Last reviewed 01/2018

Sites of atherosclerotic aneurysms include the aorta, iliac arteries, the femoral arteries, or the popliteal arteries.

Atherosclerotic aneurysms tend to be fusiform in shape and have a slowly expanding diameter. The rate of expansion of the aneurysm increases as the size as the aneurysm increases and also there is a corresponding increase in the likelihood of rupture. An abdominal aortic aneurysm that is more than 5cm in diameter is said to have a 75% risk of spontaneous rupture within a year.

In 95% of cases an abdominal aneurysm will be sited below the renal arteries. In about 25% of cases there will be more than one aneurysm present. An abdominal aneurysm may extend distal to involve one or both of the common iliac arteries. In some instances an abdominal aneurysm may extend to involve the internal iliac arteries.

Other more rare sites of atherosclerotic aneurysms include the common femoral artery and the popliteal artery. These arteries usually present as a pulsatile mass. A femoral aneurysm may occasionally spontaneously rupture; whereas a popliteal aneurysm may thrombose and present as an acutely ischaemic leg.

If a patient has aneurysmal disease then there is a tendency for all of a patient's arteries to be of large diameter.