AAA – Expansile or pulsatile?

During an abdominal exam, you routinely feel for an abdominal aorta and whether or not it is aneurysmal. This is done by placing the finger tips of each hand parallel to the outer margins of aorta. This allows you to differentiate between an expansile and pulsatile aneurysm.

An expansile AAA will expand and contract, causing your fingers to be separated with each expansion and return with each contraction. With a pulsatile AAA, you will feel the pulse during systole but your fingers will not be separated apart as the AAA does not expand and contract. Don’t forget that the aorta is an artery and being pulsatile is normal. We are only worried if the aorta’s diameter becomes more than 5.5cm and is therefore classified as an AAA. You should also consider that a pulsatile abdominal mass isn’t necessarily the aorta itself, rather another structure that is transmitting the pulses from the aorta, such as lymph nodes.