Morphological features of the development of the abducens nerve nucleus in human fetuses of different gestational periods

Abstract

As part of the brainstem, the human pons is an important relay of sensory and motor information from the brain to the cerebellum. The posterior surface of the pons in the roof area contains important vegetative structures, as well as the nuclei of the V–VIII pairs of cranial nerves. Congenital absence or hypoplasia of the nucleus of the abducens nerve can be observed in some rare diseases, such as Möbius and Duane syndrome. Many studies on the cytoarchitectural organisation of the nuclei of the abducens nerve have been conducted in animals and adult humans. Morphometry was used to estimate the size of the nucleus of the abducens nerve and to determine changes in its structure in human fetuses from 9–10 to 39–40 weeks of intrauterine development. The area of the nucleus of the abducens nerve in human fetuses from 9–10 weeks to 39–40 weeks of intrauterine development became 2.9 times larger. The fastest rate of increase in the area of the nucleus of the abducens nerve has been established in human fetuses at 11–12 weeks of intrauterine development. Slower rates of increase in the area of the nucleus of the abducens nerve have been found in human fetuses at 20–21 and 37–38 weeks of gestation. The area of neurons of the nucleus of the abducens nerve in human fetuses from 9–10 weeks to 39–40 weeks of intrauterine development increased 8.1 times. The fastest rates of increase in the area of neurons of the nucleus of the abducens nerve were found in human fetuses at 11–12 and 25–26 weeks of gestation. The slowest rates of increase in the area of neurons of the abducens nerve's nucleus were found in fetuses of 34–35 weeks of gestation.