MCBRATNEY-OWEN, B. M. ; OLSEN, B. R.; Harvard Medical School; Harvard Medical School: The Development and Comparative Anatomy of the Mouse Chondrocranium.

The anatomy and development of the chondrocranium of the mouse has not been extensively studied despite the popular use of the mouse as a model organism for skull development. Using an ontogenetic series of mouse embryos from in-bred strain C57BL/6J, the temporal and spatial pattern of the appearance of cranial base cartilages was observed. Whole mounts and sections of fetal cartilage stained embryos revealed the following general pattern. At E12.5, the fused parachordal cartilages are mostly chondrified, while none of the anterior cranial base cartilages are yet visible. By E13.5, the hypophyseal, trabecular, and orbitosphenoid cartilages are present but remain as separate anlage along the mid-line. However, by E14.5, all of the cartilages have fused to form a continuous and fully chondrified structure. The relatively small ala temporalis cartilages have also appeared, and the presumptive synchondroses are evident at this stage. These results for the mouse are compared to the published descriptions of the development and anatomy of rabbit and human chondrocrania.