Embryogenesis of intramural ganglia of the gut and its relation to Hirschsprung's disease

Abstract

<h2>Summary</h2> An embryological study on 18 human embryos and fetuses demonstrated that the myenteric plexus was formed by neuroblasts which were distributed to the alimentary tract by cranio-caudal migration druing the fifth to the twelfth week of gestation. The vagus trunks appeared to play an important role in conveying neuroblasts from the central nervous system to the esophagus, an entry of neuroblasts into the alimentary tract, while the sympathetics and pelvic parasympathics did not appear to participate directly in this process. The submucous plexus was formed by neuroblasts migrating from the myenteric plexus into the submucous layer. From these embryological findings, it was concluded that aganglionosis is a development anomaly, in which the developmental process of the intramural plexus has ceased at various stages before the twelfth week of gestation. The earlier the cessation, the longer the segment of aganglionosis. The rectosigmoid which is the most distant part for neuroblasts to travel, is the most common site of involvement. This is the classic Hirschsprung's disease.