Embolism is best described as which of the following?

• A. Thrombus that is released in the bloodstream, and can travel to the heart, lungs, and brain
• B. A stationary clot on the vessel wall
• C. A bacterial infection of the bloodstream
• D. A collection of blood outside a vessel

Answer: (A)

Embolism refers to a piece of material that travels through the bloodstream and blocks a vessel downstream. When a clot forms and then breaks free, it becomes a traveling embolus that can lodge in the heart, lungs, or brain and cut off blood flow. That is why describing it as a thrombus that is released into the bloodstream and can travel to the heart, lungs, and brain is the best choice.

The other options describe things that aren’t traveling blockages: a stationary clot on a vessel wall is a thrombus, bacteremia is bacteria in the blood, and a collection of blood outside a vessel is a hematoma.