Figure 3. Palatal fusion during embryonic development. Initially, the palatal shelves (ps) are positioned next to the developing tongue (A). Subsequently, the tongue descends, and the palatal shelves rotate toward each other (B). Finally, the palatal shelves fuse, and the midline seam (ms) is degraded by MMPs (C). The nasal septum (ns) simultanously merges with the secondary palate.