[Forms and factors of the variability of paranasal sinuses].

The form, structural variations, sex variations (connected with zygosityz), right and left positions of the sinuses were studied according to the data obtained while measuring the contours of the frontal, sphenoid and maxillary sinuses in the cranial roentgenograms made in the frontal and sagittal projections. By means of the twin method, relationship of the hereditary and environmental influences on the sinus formation was estimated. The data obtained in 111 Ukrainians (30--60 years of age), inhabitants of Vinnitsa region, mono- and dizygote twins of both sex were used. Greater dimensions in the male sinuses and a high variability of their size not connected with sex were stated. Among women the dizygote twin had larger dimensions than the monozygote ones. The sinus size is characterized by a predominant right-sided asymmetry. The hereditary effect is clearly seen in the sinus paranasales formation. A decreasing hereditary influence noted in the maxillary sinus is considered as a dependence of its dimensions on the state of the masticatory apparatus.