Features of the Individual Anatomical Variability of the Visible Surface of the Human Cerebellum

Objective - to investigate individual variability and features of variant anatomy of the visible surface of the cerebellum. The study was conducted on 197 cerebellums of people of both sexes (men – 120, women – 77), who died of causes unrelated to brain pathology (20–99 years old). During the forensic autopsy the cerebellum and brain stem were separated and fixed during one month in 10% formalin solution. Midsagittal sections of cerebellar vermis were investigated. Number of folia of gray matter, which form the visible surface of the cerebellum worm was calculated. The results were statistically processed. The visible surface of the cerebellum vermis is formed by apical folia of superficial branches of the white matter, which form the basis of ten classic lobules of the cerebellar vermis and hemispheres. The form of the lobules of the hemispheres corresponds with form of the lobules of the vermis. Number of folia of gray matter is determined by the characteristics of white matter branching: when white matter is more branched, the more folia of gray matter are at the visible surface of the vermis. It was revealed that the total number of folia of gray matter of the free surface varies from 30 to 52 folia. 30 folia were found in 0.51% of cases, 32 - a 1.02% 33 - 0.51% in the 34 - to 2.54% 35 - a 2.54% 36 - 3.55% in the 37 - to 7.61% 38 - 5.58% in the 39 - to 10.66%, 40 - to 14.21%, 41 - a 10.15% 42 - 6.6% 43 - 6.6% 44 - 6.6% 45 - 6.09% in the 46 - to 5.07%, 47 - 2 , 03%, 48 - at 3.55%, 49 - a 1.52% 50 - 0.51% in the 51 - to 1.52%, 52 leaf found in 1.02% of cases. It was established that the most common are 39, 40 or 41 folia on the visible surface of the cerebellar vermis. These variants can be used as an anatomical standard. It was found that in men average number of the folia of gray matter of the visible surface of the cerebellar vermis (41.76) significantly higher than in women (40.26) (Р = 0,01), due to the larger size of the skull and cerebellum in men and constitutional characteristics. Skull morphometric parameters (length, width, volume) and the cerebellum morphometric parameters (weight, volume, length, width, height), kraniotype, age are associated with the number of folia of gray matter of the visible surface cerebellar vermis. As a result of calculation of correlation in different age groups (20 - 29 30 - 39 40 - 49 50 - 59 60 - 69 70 - 79 and 80 - 99 years) was found that in the younger age categories ( 20 - 29 years) there is a significant positive correlation between number of the folia of the visible surface of the cerebellum and cerebellar weight (r = 0,61), volume (r = 0,59), width (r = 0,42) , length (r = 0,42). In older age groups, this correlation is gradually decreased and almost disappeared in the oldest age categories. This feature can be explained by age atrophy of the cerebellum and that the severity of age-atrophy may be different, and that reduces the dependence of the number of folia and morphometric parameters of the cerebellum. As a result of calculation of correlation in the groups with different kraniotypes (dolichokran, mezokran braсhikran, hyperbrachikran, ultrabrachikran) was found that in the dolichokran group observed a significant correlation between number of the folia of the visible surface of the cerebellum vermis and skull length (r = 0.43), the skull volume (r = 0,70), cerebellum weight (r = 0,89), volume (r = 0,88), width (r = 0,61), length ( r = 0,51). In groups with other kraniotypes significant relationship between these indicators wasn't found. The data can be used as the basis for creation of the atlases of serial sections of the cerebellum, which are based on features of the individual anatomical variability of the cerebellum.