@medical8220: A popliteal artery aneurysm (PAA) is a localized bulge or dilation of the popliteal artery, located behind the knee. It is the most common peripheral artery aneurysm, excluding those in the aorta. PAAs can be asymptomatic or cause symptoms such as leg pain, swelling, or blood clots. Treatment typically involves surgical repair, either open or endovascular.