Assessment of the Prevalence of the Circle of Willis Variations, Based on the Medico-Legal Autopsies during a 3 Year Period (2006-2009

Previous studies have indicated a correlation between variations of the Circle of Willis and some cerebrovascular diseases but the frequency of such variants has not been compared in different races. The aim of this study is to compare variation of the Circle of Willis in a limited population of Iranian people with other studies. Samples were obtained from 200 medicolegal autopsy subjects of varying ages. The circle of Willis was examined at the base of the brain. The cerebral vessels were observed for caliber and typical configuration. Variations were noted and grouped into different categories. Out of the 200 specimens examined, 69 (34.5 %) conformed to the typical pattern. In the rest of the specimens (65.5 %) there were variations in the Circle of Willis. Hypoplasia of posterior communicating arteries was the most common variation in our study. One of the autopsies showed the presence of an aneurysm (0.5%). The anatomical variations found in our study of the circle of willis were not significantly different from those reported in the literature. Based on the available studies, there is no evidence that the distribution of the variations of the circle of willis is different in various societies.