Brewer A K, Johnson D R, Moore W J
J Embryol Exp Morphol. 1977 Jun;39:59-70.
The morphology of the basioccipital, basisphenoid and mandibular bones in achondroplasic (cn/cn) mice was compared with that of normal siblings. The two bones of the cranial base were markedly reduced in length but not in width. The percentage reduction in the basisphenoid was twice that in the basioccipital bone and of the same magnitude as that previously observed in the long bones of the limbs. This difference may arise because the basisphenoid, like the long bones, grows in length from two cartilaginous growth sites while the basioccipital grows from one cartilaginous and one periosteal site. The mandible of the cn/cn mice was also reduced in size, although to a lesser extent than were the cranial bones and without the ensuing disproportion. The scale of the mandibular changes suggests that they are largely attributable to regulatory responses to the shortened cranium. The finding that the condylar cartilage of the cn/cn mice is reduced in thickness indicates, however, that the cn gene may have a direct effect on condylar chondrocytes.
将软骨发育不全（cn/cn）小鼠的枕骨基部、蝶骨基部和下颌骨的形态与正常同窝小鼠进行了比较。颅底的两块骨头长度明显缩短，但宽度未变。蝶骨基部的缩短百分比是枕骨基部的两倍，与之前在四肢长骨中观察到的幅度相同。这种差异可能是因为蝶骨基部与长骨一样，从两个软骨生长部位生长长度，而枕骨基部从一个软骨部位和一个骨膜部位生长。cn/cn小鼠的下颌骨尺寸也减小了，尽管程度小于颅骨，且没有随之而来的比例失调。下颌变化的程度表明，它们在很大程度上归因于对缩短颅骨的调节反应。然而，cn/cn小鼠髁突软骨厚度减小的发现表明，cn基因可能对髁突软骨细胞有直接影响。
