Embolism vs. Embolus

Embolism

An embolism is the lodging of an embolus, a blockage-causing piece of material, inside a blood vessel. The embolus may be a blood clot (thrombus), a fat globule (fat embolism), a bubble of air or other gas (gas embolism), or foreign material. An embolism can cause partial or total blockage of blood flow in the affected vessel. Such a blockage (a vascular occlusion) may affect a part of the body distant to the origin of the embolus. An embolism in which the embolus is a piece of thrombus is called a thromboembolism.

An embolism is usually a pathological event, i.e., accompanying illness or injury. Sometimes it is created intentionally for a therapeutic reason, such as to stop bleeding or to kill a cancerous tumor by stopping its blood supply. Such therapy is called embolization.

Embolus

An embolus (plural emboli; from the Greek ἔμβολος “wedge”, “plug”) is an unattached mass that travels through the bloodstream and is capable of clogging arterial capillary beds (create an arterial occlusion) at a site distant from its point of origin. There are a number of different types of emboli, including blood clots, cholesterol plaque or crystals, fat globules, gas bubbles, and foreign bodies.

By contrast there are non-traveling blockages that develop locally from vascular trauma or epithelial pathology and vascular inflammation — such as atheromata and thrombi. However, if a thrombus breaks loose from its genesis site it becomes a thrombo-embolus and if not broken down during transit, may cause embolism(s).

The term was coined in 1848 by Rudolf Virchow.