Palatal regions along the AP axis in mice. (A–D) H&E-stained coronal sections of an E14.5 mouse embryonic head showing anterior, middle, posterior, and posterior end regions. (E–H) H&E stained coronal sections of an E15.5 mouse embryonic head showing anterior, middle, posterior and posterior end regions. Arrowheads in (E,F) indicate maxillary ossification. Arrow in (G) indicates palatine bone ossification. Arrow in (H) indicate cartilages in the pterygoid process. (I) Inferior view of partially fused palatal shelves of an E14.5 mouse embryo. Dotted lines indicate the equivalent position of coronal sections shown in (A–H). A, anterior; M, middle; P, posterior; Pe, posterior end. (J) Inferior view of a 3D rendered microCT scan of an E18.5 mouse embryonic head showing skeletal patterns in the palate. pm, premaxilla; ppm, palatine process of the maxilla; pb, palatine bone; pp, pterygoid process. (K) Von Kossa-stained coronal section of an E15.5 mouse embryonic head showing both maxillary (arrowhead) and palatine bone (arrow) ossification in the middle region. cnp, common nasal passage; ns, nasal septum; ps, palatal shelf. Scale bars in (A) for (A–H), 1 mm; in (I), 500 μm; in (K), 200 μm.