(A, B) Intraoral views of palates from control and Osr2-Cre;Runx2fl/fl mice at newborn stage (P0). Arrow indicates the cleft in the posterior part of the soft palate. (C–F) Sagittal (C–D) and coronal (E–F) views of microCT scans of newborn control and Osr2-Cre;Runx2fl/fl mice (N = 3). Red arrows indicate the normal soft palate, and asterisks indicate the cleft in the posterior part of soft palate. (G–P) H and E staining of soft palate coronal sections from control and Osr2-Cre;Runx2fl/fl mice at P0 (N = 5). Yellow dashed lines outline the soft palate muscles. Black and red arrows in H and M show the pterygoid plate and tensor veli palatini (TVP) defects, respectively, of Osr2-Cre;Runx2fl/fl mice. Asterisks in N indicate the cleft soft palate in the levator veli palatini (LVP) region of Osr2-Cre;Runx2fl/fl mice. Boxed areas in G, I, L, and N are enlarged in H, J, M, and O, respectively. Boxed areas in J and O are enlarged in K and P, respectively. Scale bars in C-D and E-F indicate 0.5 mm and 0.9 mm, respectively. Scale bar in G indicates 400 µm for G, I, L, and N. Scale bar in H indicates 100 µm for H, J, M, and O. Yellow arrowheads in P indicate the centralized nuclei in mutant muscle cells.