Fig. 2. Gross bony structures and histology of P1 Fgfr2^+/S252W mice. (A,C,E,G,I,K,M,O,Q,S) Control littermates; (B,D,F,H,J,L,N,P,R,T) corresponding regions in mutant mice. (A-H) Alizarin Red S and Alcian Blue staining of (A-F) the skull and (G,H) the chest. (I-R) HE staining of the (I,J) brain, (K,L) palate, (M,N) trachea, (O,P) lung, and (Q,R) growth plates of long bone. (S,T) TRAP staining for growth plates. The mutant mice have: a wide interfrontal suture (B, arrows define the width of the suture); a shortened nasal snout (D, arrow); fusion of the joints between the zygomatic arch bones (F, arrows); a sternum with abnormal fusions and bifid xiphoid process (H, arrow); hydrocephalus with enlarged ventricles (J, arrows); a palate defect (L, arrow); a complete cartilage sleeve of the trachea with abnormal cartilage thickening (N); atelectasis of the lungs with alveolar proteinaceous fluid (P); chondrocyte hypertrophy and disorganization with irregular and thickened ossifying cartilaginous spicules in the growth plates of long bone (R); and decreased osteoclasts at the chondro-osseous junction (T; S, arrow shows normal osteoclasts stained red). LV, lateral ventricle; 3V, third ventricle; TC, tracheal cartilage; P, zone of chondrocyte proliferation; H, zone of hypertrophy; M, zone of mineralization; O, zone of ossification at the chondro-osseous junction. Scale bars: A-H, 1 mm; I-T, 50 µm.