An embolus is best described as what?

• A. A traveling clot dislodges and blocks a vessel
• B. A stationary clot within a vessel
• C. An infection of the heart lining
• D. A tear in the artery wall

Answer: (A)

An embolus is a traveling mass that breaks loose and is carried by the bloodstream to a distant site, where it can lodge in a small vessel and block blood flow. The essential idea is movement through the circulation and sudden obstruction of a vessel, which is what the description “a traveling clot dislodges and blocks a vessel” conveys.

In contrast, a stationary clot forms and stays in place at its origin (a thrombus), an infection of the heart lining describes endocarditis, and a tear in the artery wall refers to dissection. These scenarios do not capture the traveling, blocking behavior of an embolus.