[Redundancy of the main cerebral arteries in morphological variations of the Willis circle].

The study presents a computer simulation of the cerebral blood flow in three variants of the circle of Willis. The redundant function of the circle of Willis during occlusion of the internal carotid and basilar arteries was estimated. The major role of the circle of Willis in the redistribution of blood to certain areas of the brain in periods of flow disturbances is pronounced. Complete maintenance of the cerebral blood flow (without any additional autoregulatory mechanisms) during occlusion of the vertebro-basilar or internal carotid systems in some morphological variations of the circle of Willis was demonstrated.