Difference between Thrombus and Embolus

In a healthy human organism blood flows smoothly through the vessels. Sometimes, as a result of arteriosclerosis or other conditions, blockages start to form in the vessels. There are two types of blockages, and they are known in medicine as thrombi and emboli. In this article, we will examine the differences between the two.


Thrombus vs Embolus
A schematic representation of a clot (thrombus) on the blood vessel

A thrombus is a component of blood that is formed in blood vessels. Components such as platelets or fibrin usually form when the human organ is injured. Clots prevent blood from flowing and this eventually results in a tissue forming.

Many clots originate in the legs and often caused by inactivity. These are referred to as DVT, or deep vein thrombosis.

Symptoms of thrombosis include shortening of breath, chest pain and swelling. Still, there are often no symptoms of DVT at all.

People can reduce the risk of thrombosis by periodically flexing and extending their legs and taking long walks during periods of physical inactivity. There are special compression socks that are designed to increase the blood flow. The other recommended methods of preventing arteriosclerosis include eating low cholesterol food, such as fruits, vegetable, and cereals.

In this Illustration you can see how thrombus becomes embolus

An embolus is a piece of a thrombus that splits from it, and moves further through the bloodstream directly to the human brain or other organ. Emboli move in the bloodstream until they reach a narrowing in an artery through which they cannot pass. When stuck, they significantly reduce the blood flow to downstream tissues of the human organism, which makes these tissues ischemic, i.e. causing a state when oxygen and glucose are insufficient to meet metabolic demand.

If an embolus ends up in the human brain, it most often results in a stroke. If an embolus lands in the heart, there is a high probability of heart attack. If it ends up in the lungs, it will cause pulmonary embolism. The lungs are especially vulnerable to embolism, because blood passes through this organ, every time it flows to and from the heart. If a large number of clots bombard the lungs, there is a lethal risk.

Thrombus vs Embolus

What is the difference between Thrombus and Embolus?

When a blood clot forms in a blood vessel it is a thrombus. If, on the other hand, this clot travels further into the body, it is an embolus.

The term thromboembolus is often used in medicine because most emboli arise from thrombi. Some thrombi never become emboli, but are as dangerous for the human organism as emboli, and need to be clinically treated. Most emboli are thrombi, albeit in some cases bits of plaque, fat, air bubbles, and other material form into an embolus. All of these also qualify as emboli.

Both thrombi and emboli can be treated with anticoagulant medications that help to dissipate the clots. Sometimes also special “umbrella stands” are inserted to catch the clots. The other way to treat both types of clots is to remove them surgically.

Comparison chart

A thrombus An embolus
Is static Is moving until it reaches a narrowing in the vessel
Some thrombi do not become emboli Most emboli arise from thrombi
Consists of blood components Sometimes consists of fat, air bubbles, and other formations