The popliteal artery can become abnormally dilated, forming an aneurysm. The artery is considered aneurysmal when its diameter exceeds 7 mm. Although popliteal artery aneurysms can occur in isolation, they are most commonly associated with aneurysms in other large vessels such as the femoral artery or the thoracic or abdominal aorta. Therefore, once a popliteal aneurysm has been detected, the entire arterial tree needs to be investigated for the presence of coexisting aneurysms elsewhere in the body.