Which term refers to a moving clot that blocks a vessel?

• A. Embolus
• B. Thrombus
• C. Virchow triad
• D. Burkitt lymphoma

Answer: (A)

An embolus is a moving clot that travels through the bloodstream and can lodge in a vessel to cause a blockage. This distinguishes it from a thrombus, which forms in place on a vessel wall and may grow there rather than travel. Often an embolus can originate from a thrombus that has broken loose, becoming a thromboembolus as it moves. Clinically, this explains events like a deep vein thrombosis sending a clot to the lungs (pulmonary embolism) or a clot traveling to the brain or heart.

The other terms don’t describe a moving clot: a thrombus is the stationary clot attached to a vessel wall; Virchow triad refers to risk factors for clot formation; Burkitt lymphoma is a type of cancer.