Early histomorphogenesis of metencephalon in goats

Early development of the metencephalon was studied using six goat foetuses up to one month of gestation. By 24 days of age (1.4cm CRL), the neural tube was completely fused and the brain vesicles started developing. The metencephalon was distinguished from the more posterior myelencephalon by its much thicker roof and by the presence of the isthmus and the pontine flexure. It was circular in cross section and distinct basal and alar plates representing the motor and sensory areas were found on each side of the midline and were united by the floor and roof plates, respectively. A prominent sulcus limitans divided the alar and basal laminae. The walls bore the prominent scalloping of neuromeres. Near the beginning of the hindbrain were the large semilunar ganglia. Junction between metencephalon and myelencephalon was demarcated by the sharply defined otocyst. All the metencephalic parameters showed a significant positive correlation with the parameters of the other brain vesicles. Histologically, wall of the metencephalon showed an inner ependymal, middle mantle and outer marginal layers bounded by the inner and outer limiting membranes.