A study on morpho-histogenesis of human foetal pons

Abstract

Introduction: During the second month of intra uterine life, the metencephalon widens and the cells of the metencephalon present in the ependymal zone migrate into mantle and marginal zones and assume the adult position by 12th week of intrauterine life. The cellular collection constituting the various nuclei of tegmentum of pons is very much striking amidst reticular formation. Materials and Methods: Out of 100 foetuses obtained, foetuses with a difference of two weeks gestation from first trimester to third trimester have been taken for the study (10wks,12wks, 14wks,16wks, 18wks, 20wks, 22wks, 24wks, 28wks, 32wks, 36wks and 40wks). Results: The length of the pons increased from 3mm to 2cms and width increased from 5mm to 1.8 cm. The neurons in the earlier gestations are small and round. By the end of third trimester, they became large spindle (fusiform) shaped and multipolar. Conclusion: Knowledge of the migration of neurons to form nuclear groups is essential for defects of the basal ventricular zone result in defects of specific cranial nerve nuclei such as the abducent and facial nerves and for any prenatal evaluation in cases of suspected of brain anomalies Keywords: Abducent nucleus, Facial nucleus, Multipolar neurons, Spindle shaped neurons.