Thomas Willis and the Willis Polygon

Well, I don’t know about Thomas, but if you are a medical student and you have already passed the first period of college, surely you must have heard of the Polygon named Thomas Willis, the famous Polygon of Willis . During the classes of the dreaded neuroanatomy , you studied the formation, function and main pathologies associated with it. And he also smelled a lot of formaldehyde during the long afternoons and nights he spent studying anatomical, with the pieces on the bench and the lesson plan beside them, to understand this complex system formed at the base of the brain that was evidenced by Thomas Willis.

Thomas Willis

Thomas Willis was born on January 27, 1621 in the city of Bedwyn, England. Son of farmers and the youngest of the family, he studied high school at the Edward Silvester School. Before becoming a doctor, he graduated from the Faculty of Arts in 1639, also completing a master’s degree in the artistic field. He entered the medical school at the University of Oxford, England, after the civil war that occurred in that region, completing his medical course and receiving his bachelor’s degree in 1646. Soon after graduation, he started working as a medical advisor having visited several villages close to Oxford. He spent so much time at that university that it was there that he found his great love, joining in marriage with the daughter of the Oxford Vice Chancellor, Mary Fell. Pregnant Mary 9 times, however, only four of their children had the opportunity to live a long life with their parents. Later, in 1660, he started his teaching career as a professor of Philosophy at the University of Oxford, the same one he graduated from, for 15 years.

An important event that marked Thomas Willis’ career as a doctor happened in 1650, the year in which Anne Green was convicted of infanticide and sentenced to hanging. His body was donated to the Oxford study center, a fact that made Willis very excited, because with the arrival of a new piece he could improve his studies on the nervous system. However, when Anne’s body reached the anatomical Oxford and Willis went to remove it from the coffin in which it arrived to preserve it, he realized that Anne held a brief sigh. With that, he and a friend who accompanied him started resuscitation techniques, aiming to revive her, and were successful.

In 1667, the doctor who described Willis’ polygon moved to London, where he built his own clinic. After the death of his wife Mary, he married Elizabeth Calley, who was also a widow.

During his years of study, Thomas has devoted much of his career to deepening his research in the area of ​​anatomy and physiology, especially the nervous system. It is known that the components of this system were already well known, but no researcher had combined the functions of each device that was part of the nervous system as if it were a single set, capable of performing the same function. Therefore, he worked in the anatomical of his college, carrying out various experiments on animals (such as fish, amphibians and reptiles) until he reached the result he was looking for. Result that, at that time, Thomas never imagined that he would take these proportions.

But what was in that study?

By dissecting the nerve tissue of guinea pigs, Willis was able to accurately demonstrate the path of these nerves entering and leaving the cranial box, thus connecting to the brain. And do not stop there! It also showed the automatic reactions that were carried out by these nerves, in addition to diagnosing the role of vessels in the cranial base that were shaped like a polygon, so much so that they received the name Thomas Willis as a reward for their studies. However, his studies went beyond research and experiments in human anatomy and physiology, when the discoverer of the Willis Polygon became one of the doctors to describe the semiology of migraine, myasthenia and epilepsy.

Contributions to medicine

Thomas Willis in addition to being a doctor, anatomist and physiologist, stood out throughout his life in his authoring career. He wrote several books, including his most famous book at that time, called “ Cerebri Anatome” , that is, the anatomy of the brain. In that book he preached his ideas according to what he had witnessed and found in the long years he spent studying. One of these ideas was that the brain, like its components, was the most important organ in the entire human body. Another very important publication was in 1667, when he published the book “ Pathologicae cerebri, et nervosi generis specimen”, this book that contained an extensive study that Willis had carried out and that involved factors of the pathology, as well as of the neurophysiology of the human brain. It was in this same work that he reported the discovery about the etiology of seizures and other convulsive disorders, theories that helped psychiatry worldwide in the early diagnosis of these diseases.

He was the first professional to name cranial nerves ! This nomenclature even though we use it today (I, II, III, and so on). And also the first to diagnose myasthenia gravis in 1671, a pathology that presents itself as a muscular fatigue of a chronic characteristic in which the patient progresses with progressive paralysis. Another finding that, although not related to neurology is part of the study of medical practice in general, was that Thomas started to use sweet urine as a diagnostic criterion for diabetes mellitus, a criterion that had long since fallen apart.

Willis polygon

Thomas, as previously mentioned in his contributions to medicine, described in detail the vascularization of the brain. Recalling your neuroanatomy classes, you learned that the brain is vascularized by two main groups: the vertebro-basilar (or vertebral arteries) and carotid (internal carotid). When these systems become confluent at the base of the skull, they form a polygon, which was named after the great researcher who discovered it: Thomas Willis. This polygon is formed by the following arteries: posterior cerebral, anterior communicating, internal carotid, posterior cerebral and posterior communicating. The importance of this polygon is reflected in what has been called brain circulation redundancy. This phenomenon is important because, As an obstruction or stenosis occurs in any of these arteries belonging to the polygon, cerebral circulation in general is not significantly impaired, as the other arteries are able to supply the deficiency of any of them. This fact is extremely important in the case of cerebral embolisms or conditions that promote stenosis of the cerebral arteries, decreasing the extent of the damage suffered by these patients.

Final considerations

Known as the “father of neuroscience”, Thomas Willis left us on November 11, 1675, at the height of his 54 years, due to complications from a disease called pleurisy, where inflammation of the pleura occurs (the layer that lines our lungs and our rib cage). Although he left early, Willis left legacies for life. So much so that, today, there is no doctor or medical student who does not know Willis’ polygon or at least has never heard of it. His contribution to the field of health was such that naming a finding with his name is little compared to the benefit that public health gained from it. After reading this article carefully, I hope you have been touched by the life story of the creator of the most important polygon in the world: the Willis polygon!


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