The mandible is also broadly U-shaped in this embryo, which is the same size as the previous one. The anterior ends of Meckel’s cartilage continue to be typically bulb-shaped upward and well in contact, but still well demarcated from each other by a perichondrium. The bony symphysis remains open by about 300 μm. The bony groove, in which the inferior alveolar nerve runs, is already somewhat more markedly developed in this embryo (Figs. 10.1, 10.2, and 10.3).