Prenatal morphogenesis of the human mental foramen

The mental foramen, at first glance, merely looks like a hole where the mental nerve and the vascular bundle runs through. From a morphogenetic point of view, however, the mental foramen is a suitable model to study the development of a structure where different components are involved. To understand this developmental process, a three-dimensional description at different developmental stages first has to be given. From histological serial sections of human embryos and fetuses, ranging in size from 19 to 117 mm crown rump length (CRL), three-dimensional reconstructions of the foraminar regions were made. Outline and form of the developing foramen, size, course of the mental nerve and the adjacent blood vessels could be shown in detail. In this way, the formation of these structures became concrete in three dimensions. In the future, to understand the mechanisms regulating this complex system, where a nerve and blood vessels became successively surrounded by bone, molecular biological data have to be correlated with morphological findings.