Which term describes a sudden blockage of a vessel by an embolus?

• A. Thrombosis
• B. Hemorrhage
• C. Embolism
• D. Aneurysm

Answer: (C)

Embolism is a sudden obstruction of a blood vessel caused by an embolus that has traveled through the bloodstream from another site and lodges in a distant vessel, abruptly cutting off blood flow. The embolus can be a clot (thromboembolus), fat, air, tumor material, or other debris. This differs from thrombosis, where a clot forms at the site of a vessel and narrows or blocks flow locally rather than traveling to a new location. Hemorrhage is bleeding due to vessel rupture, and an aneurysm is a weakened, dilated segment of a vessel that can rupture later. In clinical scenarios, embolism can manifest as a stroke if it affects the brain or a pulmonary embolism if it blocks a pulmonary artery.