[Atherosclerosis of the vessels of Willis' circle in certain variants in its structure].

Random studies of the base of the brain vessels in 278 men who had died at the age of 50--64 years were carried out; 29 variants of the structure of the circle of Willis were established; the most common were threadlike connective arteries and posterior trifurcations of the inner carotid arteries. The investigation of atherosclerotic changes in every vessel of the base of the brain showed that in the so-called posterior trifurcations there was a statistically reliable growth of the average degree of atherosclerosis in the intracranial region of the inner carotid artery ensuring in these cases the blood supply for a considerably greater region of the brain. In posterior connective arteries atherosclerotic changes were revealed only when their diametre exceeded 0.1 cm which testified to the bloodflow in these arteries.