What is a blood-filled sac dilation of an artery commonly known as?

A blood-filled sac dilation of an artery is commonly referred to as an aneurysm. When this aneurysm ruptures, it can lead to significant internal bleeding and heightened risk of mortality. Hence, a ruptured aneurysm describes a critical condition where the aneurysm has burst, causing blood to escape from the vascular system and potentially leading to life-threatening consequences.

The other options represent different medical conditions. For instance, aortic dissection involves a tear in the artery wall but does not refer specifically to a dilation or rupture. Varicose veins pertain to distended veins primarily in the legs and are not associated with arterial dilation. A thrombus refers to a blood clot within a vessel, which, while serious, is not characterized as a dilation of an artery. Understanding these distinctions is crucial in the context of vascular pathologies.