Variations in the structure of circle of Willis in people with cerebral circulation disorders who died from other reasons
Objectives. To establish the variations in the structure of circle of Willis in people with cerebral circulation disorders who died from other reasons for the identification of variants predisposing to cerebrovascular disease development.
Material and methods. Variations in the structure of circle of Willis were studied on the brains of 500 deceased humans whose cause of death was not associated with cerebral ischemia and by means of computerized tomography in 100 people with this pathology.
Results. In 38% of cases the circle Willis in persons whose cause of death was not associated with cerebral circulation disorders was in its classical variant, in 19% of cases posterior trifurcation of internal carotid artery was observed, in 17,5% of cases - aplasia of the posterior connecting artery, in 11,5% «rare variants» were observed and 14% of cases belonged to a combined type. No cases of classical variant of circle of Willis were revealed in individuals with cerebral circulation disorders. Among the atypical (non-classical) variations most commonly were found: aplasia of one (25%) or two (21%) posterior connecting arteries, posterior trifurcation of internal carotid artery (26%) and the combined type of the circle of Willis (28% of cases).
Thus, for regulation of blood flow in the brain the classic version of the structure of the circle of Willis is the best. Nonclassical variants of arterial circle, especially aplasia of both posterior connecting arteries, can predispose to the development of circulatory disturbances in the brain.
Key words: brain, circle of Willis, arteries.
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