[The structure of the arteries of the base of the brain in saccular aneurysms].

In 100 autopsy observations with saccular aneurysms of diverse localization the structure of arteries at the base of the brain was studied. In 26 per cent of the cases this structure was of the normal or "classic" type. In some instances there could be detected deviations from the "classic" type, with a tendency in certain localization of the aneurysm towards hypoplasia of the proximal length of the anterior cerebral artery. Frequently encountered divergences from the "classic" type of the structure come as a result of a delayed development of the vessels at the base of the brain during early stages of ontogenesis.