【摘要】 观察1600个成入颅骨,顶间骨出现率为2.94％,皆在枕骨上项线上方,其中27.69％与最上项线交叉。观察60例7—38周龄胎颅的枕鳞上部以两个骨化中心进行膜内化骨的情况。本文认为顶间骨的形成是由于枕横裂未融合及异常骨化中心出现所致,并提出枕鳞上部与枕鳞下部之间的融合线位于上项线以上,而上项线和最上项线均不应认作是两部融合线的观点。更多还原

【Abstract】 1600 skulls were observed. The appearance rate of interparietals is 2.94%. All the interparietals appear above the superior nuchal line, and 27.6% of them cross over the highest nuchal line. The upper parts of occipital squama of 60 fetal skulls of 7-38 weeks were studied, ossifications were developing around two centers in the form of endomembranous. The author holds that the formation of interparietals resulted from the failure of the transverse occipital fissure to fuse together and the forming of the abnormal ossified center. The author also suggests that the fusion between the superior region and the inferior region of the occipital squama occurs above the superior nuchal line. Both the superior and the highest nuchal line should not be considered as the fusing line of the two regions.更多还原