- Circle of Willis
- The circle of Willis is an arterial circle of critical importance at the base of the brain. It is called an arterial anastomosis, a joining of arteries. The circle of Willis receives all of the blood pumped up the two internal carotid arteries (that come up the front of the neck) and the basilar artery formed by the union of the two vertebral arteries (that come up the back of the neck). All of the principal arteries supplying cerebral hemispheres of the brain come off of the circle of Willis. .
* * *circle of Wil·lis -'wil-əs n a complete ring of arteries at the base of the brain that is formed by the cerebral and communicating arteries and is a site of aneurysmsWillis Thomas (1621-1675)British physician. One of the major figures of English medicine in the 17th century, Willis was a founder of the Royal Society. With all his notable achievements, he is known especially for his extensive study of the nervous system. In 1664 he produced Cerebri Anatome („Anatomy of the Brain”), the most complete and accurate description of the nervous system up to that time. This work contained his description of the circular anastomosis of arteries at the base of the brain that is now known as the circle of Willis. His description was not the first but it was the first complete one and was accompanied by an equally complete illustration.
* * *circulus arteriosus cerebri.
Medical dictionary. 2011.