Circle of Willis Diagram

What is the Circle of Willis?

is an arrangement of arteries located in the base of the brain. It is connected to the brain’s major arteries, and its function is to supply consistent blood flow between the brain’s anterior and posterior arteries. This circular part of the brain was named after Thomas Willis, an important figure in the history of anatomy, neurology, and psychiatry. He was the one who first described this arrangement of arteries centuries ago.

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Who knew that our brain had such a nifty segment? In the event that one of our brain’s major arteries becomes narrow (which slows down blood flow) or there is a blockage (blood flow stops), the Circle of Willis will work to maintain blood circulation by redirecting the blood flow to interconnected branches. This redirection is called collateral blood flow, which means that alternative routes will be used in case blood flow is disrupted due to an artery being damaged, narrow, or blocked.

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In order for people to know what this arrangement of arteries looks like, a diagram was created so that people can see how the arteries are spread out and what parts of the brain they are connected to. It’s perfect for neurologists and doctors because it serves as a reminder of what it looks like and can be used for educational purposes.

What will you see in a Circle of Willis Diagram?

A diagram is a simple graphical representation of a subject that shows what it looks like and what comprises it.

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The most common Circle of Willis diagrams simply show the Circle of Willis without the brain in the background, though some do include this so people can see exactly where it is in the brain.

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The Circle of Willis is colored red in these diagrams, and it shows all the arteries that it is connected to, so you should see text labels of the following:

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• Anteromedial Central Arteries
• Anterior Choroidal Artery
• Internal Carotid Artery
• Ophthalmic Artery
• Middle Cerebral Artery
• Anterior Cerebral Artery
• Recurrent Artery of Heubner
• Anterior Communicating Artery
• Posteromedial Central Arteries
• Posterior Cerebral Artery
• Posterior Communicating Artery
• Superior Cerebellar Artery
• Pontine Arteries
• Basilar Artery
• Anterior Inferior Cerebellar
• Labyrinthine Artery
• Posterior Inferior Cerebellar Artery
• Vertebral Artery
• Anterior Spinal Artery

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Some Circle of Willis diagrams don’t just label each artery. Some of these diagrams have short descriptions of what they are and where they are connected to in the brain. These versions of the diagram are often used for educational purposes, specifically for medical students looking to become neurologists and neurological surgeons.

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The explanation-less versions of the diagrams can also be used for educational purposes even if they don’t have text explanations on the diagram itself.

When is it best to use a Circle of Willis Diagram?

That depends on you! In the previous section, we mentioned that doctors often have anatomical charts on display in their offices. If you want an anatomical diagram of the Circle of Willis in your office, you can print our PDF for that purpose! It might be good to have one because it can serve as a reminder for yourself about the anatomy of that circular arrangement of arteries in our brains.

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This diagram can also be used for education purposes. Let’s say you are a doctor working as an educator for a medical school, and you’re tasked to create a textbook for students in neurology, you can use this diagram and follow it up with glossary pages to discuss what their individual parts are for.

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You can print several copies to hand out to students, and you can attach them to your PowerPoint slides when conducting lectures about the Circle of Willis. If you give handouts of this PDF file to your students, they can use it to take notes for reviewing during exam seasons.

What are the benefits of using a Circle of Willis Diagram?

Use as a refresher.

The Circle of Willis Diagram can be put on display in the offices of neurologists so they can refresh their memory about the purpose of the Circle of Willis, what it looks like, what parts make it, and what their purposes are.

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Students who were given handouts of this diagram can take advantage of spaces to jot down bullet point notes about the Circle of Willis and its parts.

Educate neurology students.

Doctors who work as medical school professors can use this diagram when lecturing students about the brain’s anatomy. They can zoom into the different parts of the Circle of Willis whenever they are discussing the functions of each part.

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As mentioned earlier, medical school educators can also include this in any neurology textbook they are tasked to create, then they can follow up with pages all about the Circle of Willis and its parts.

Educate patients and their loved ones.

Just as it can be used to educate medical school students, the Circle of Willis Diagram can be used to educate patients and their loved ones. If the patient is dealing with a brain-related problem like an aneurysm, doctors can educate the patient about the Circle of Willis, how aneurysms affect it, and what can be done to treat it, as well as any risk that recommended treatments might have. If the patient isn’t cognizant or can’t really be educated because they are asleep/unresponsive or in a coma due to an aneurysm or some other neurological problem, doctors can educate their loved ones instead. Both parties have the right to know about the Circle of Willis in this context because they have the right to consent to certain treatments or back out because of the risks. Educating them is one way to help them discern what they want.