Circulus arteriosus cerebri: Anatomical variations and their correlation to cerebral aneurysms
The anatomical structure of circulus arteriosus cerebri was first described by Thomas Willis in 1664. Many variations in the circulus arteriosus cerebri have since been reported. The extent to which anatomical variations within the circle influence aneurysm formation in a South African sample has not yet been established. The results of such a study would be of value to clinicians treating patients with vascular diseases. The aim of the study was to determine if there is a correlation between arterial variations in the circulus arteriosus cerebri and cerebral aneurysm formation. The brains of 39 cadavers at the Faculty of Health Sciences were removed and the circulus arteriosus dissected. In addition, 113 patients who underwent a MRI or MRA of the circulus arteriosus cerebri at the Department of Radiology at the Groote Schuur Hospital, Cape Town were included. For both of these samples the anatomical variations and any aneurysms present were documented. The external diameters of the arteries forming the circulus arteriosus cerebri were also measured. No aneurysms were found in the cadaver sample, thus the correlation could not be tested. In the sample of images from the 113 patients, 111 images showed one or more anatomical variation of the circulus arteriosus cerebri. Of these, 59 had one or more cerebral aneurysm and 52 had no aneurysms. Statistical analysis showed no significant correlation between cerebral aneurysms and anatomical variations in the circulus arteriosus cerebri for a South Africans ample. This is contradictory to what is seen in the literature. Further investigation is required to establish the reason why the results from this South African sample differ from the results reported in the international literature.
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Division of Clinical Anatomy and Biological Anthropology