[Anatomic configuration of the circle of Willis in the adult studied by injection technics. Apropos of 100 brains].

This study has been realized on one hundred Moroccan brains taken from medico-legal autopsies. Its aim is a morphological study of the arterial circle of the base and frequency of the malformations of the cerebral vasculoris. Those investigations have been realized with the help of a synthetical resin injection, which allowed us to get into the following conclusions. 15 types of Willis' polygonals have been identified among which 14 would be assimilated to the polygonals already described by G. Lazorthes. The 15th is original and seems proper to our series. At the same time the systematic research of the aneurysms at the brain base level has allowed us to identify a case situated at the level of the internal carotide at the origin of the anterior cerebral artery. The few brains injected did not permit us to get into sound statistical conclusions. Even though they incit further searches in practical clinics. Our actual results are just preliminary and we contemplate doing more complete studies in order to find a new approach of classification and systematisation of the Willis' polygonal, as well as the frequency of the malformations of the cerebral vasculoris.