Jolly R J, Moore W J
J Embryol Exp Morphol. 1975 Jul;33(4):1013-22.
Skull morphology in achondroplasic (cn/cn) mice was compared with that of normal siblings in order to determine the effects of this chondrodystrophy on skull growth, particular attention being given to dimensions reflecting growth at the synchondroses of the cranial base, the nasal septal cartilage and the condylar cartilage of the mandible. The central section of the cranial base (basicranial axis) was reduced by 25 percent, the length of the viscerocranium by 18 percent and the length of the condylar process by 11 percent. The evidence indicates that these reductions are due to diminished growth at respectively the spheno-occipital and missphenoidal synchondroses, the nasal septal cartilage and the condylar cartilage. The relative sizes of the reductions in cranial base, vicerocranium and condylar process suggest that the growth of synchondrotic and septal cartilages is diminished to a greater extent than that of condylar cartilage. This finding is in agreement with the observations that condylar cartilage, unlike synchondrotic and septal cartilage, grows by surface apposition and that the principal defect in cn/cn mice is a disturbance of interstitial cartilaginous growth. The posterior extension of the basicranial axis of the cn/cn mice was reduced by 14 percent and the anterior extension by 2 percent. The width of the cranial base was decreased by 9 percent and the angle between the basicranial axis and its anterior extension was decreased by 3 percent. The length of the neurocranium was reduced by 19 percent in the cn/cn animals while the volume of the endocranial cavity was diminished by only 18 percent. The latter reduction is less than would be expected from the cube relationship between volume and linear dimensions but is readily accounted for by the lack of reduction in the height or width of the neurocranium, the slight flattening of the cranial base and the doming of the neurocranial vault.
为了确定这种软骨发育不良对颅骨生长的影响，对软骨发育不全（cn/cn）小鼠的颅骨形态与正常同胞的颅骨形态进行了比较，特别关注反映颅底、鼻中隔软骨和下颌骨髁突软骨生长的尺寸。颅底中央部分（基本颅轴）缩短了25%，面颅长度缩短了18%，髁突长度缩短了11%。有证据表明，这些缩短分别是由于蝶枕和蝶骨间软骨结合、鼻中隔软骨和髁突软骨生长减少所致。颅底、面颅和髁突缩短的相对大小表明，软骨结合和鼻中隔软骨的生长减少程度大于髁突软骨。这一发现与以下观察结果一致：与软骨结合和鼻中隔软骨不同，髁突软骨通过表面附着生长，且cn/cn小鼠的主要缺陷是软骨间质生长紊乱。cn/cn小鼠基本颅轴的后延伸缩短了14%，前延伸缩短了2%。颅底宽度减少了9%，基本颅轴与其前延伸之间的角度减少了3%。cn/cn动物的脑颅长度减少了19%，而颅腔体积仅减少了18%。后一种减少小于根据体积与线性尺寸之间的立方关系所预期的减少，但很容易通过脑颅高度或宽度没有减少、颅底轻微变平和脑颅穹窿隆起得到解释。
