Histomorphometry of the cortical layers and the dentate nucleus of the human fetal cerebellum

Objectives: This study was aimed at determining the histomorphometry of the cerebellar cortical laminae and the dentate nucleus of the human fetal cerebellum; the number and shape of the neurons; and the gestational age of appearance of the cerebellar folia, white matter and arbor vitae cerebelli.Methods: Microscopic sections of the human fetal cere-bellum stained with hematoxylin and eosin and Biel-schowsky silver stain were studied.Results: The thickness of the cortical laminae of the hu-man fetal cerebellum varied among gestational weeks as follows: external granular layer: 36.06 +/- 9.36 -50.05 +/- 34.06 gm, molecular layer: 32.76 +/- 17.16 -52 +/- 28.6 gm, Purkinje cell layer: 9.36 +/- 6.8 -15.6 +/- 4.68 gm and internal granular layer: 66.65 +/- 24.42 -146.63 +/- 47.79 gm. Similarly, the number of neurons per field of view at 1000X under a compound microscope varied among gestational weeks as follows: external gran-ular layer: 89.92 +/- 42-142.84 +/- 50, molecular layer: 15 +/- 12.5-25 +/- 8.25, Purkinje cell layer: 3.5 +/- 1-5 +/- 2.5 and internal granular layer: 98.5 +/- 69.75-224 +/- 47. White matter in the fetal cerebellum was already present at the age of 12th gestational week, whereas cerebellar folia appeared at 16-20 gestational weeks. Arbor vitae cerebelli and the dentate nucleus became conspicuous after the 20th gestational week. Fetal neurons were round except for Purkinje cells.Conclusions: The thickness and neuronal counts of the human fetal cerebellar cortical layers and the measure-ments of the dentate nucleus along with other histo-morphological features varied with gestational age from the 12th week of gestation until birth.(c) 2022 The Authors. Production and hosting by Elsevier Ltd on behalf of Taibah University. This is an open access article under the CC BY -NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).