Figure 1.

Human palatal development. (A) Week six of human palatal development, with the secondary palate shown vertically on each side of the tongue and a gap between the secondary palate, nasal septum and primary palate. (B) After descent of the tongue, the secondary palatal shelves elevate and orient horizontally, allowing them to come in contact and begin fusing. (C) Fusion of the primary and secondary palate and the nasal septum separating the oropharynx from the nasopharynx. Figure modified from Dixon et al.¹