Vilmann H, Moss M L
Scand J Dent Res. 1979 Jun;87(3):171-7. doi: 10.1111/j.1600-0722.1979.tb00669.x.
During growth the rat skull straightens considerably due to flexions between skull parts and individual bones. This straightening is defined as orthocephalization. Orthocephalization might also be caused by a change in head posture during growth, i.e. it may be "apparent". In order to study the significance of this phenomenon, radiographs of dried skulls of male rats, 14, 30 and 60 d of age were subjected to angular measurements between the plane of the lateral semicircular canal and the plane of foramen magnum and of the basisphenoid bone, respectively. When the plane of the lateral semicircular canal is placed horizontally, the head is claimed to be in natural position. No changes in the angulation between the lateral semicircular canal and the basisphenoid bone could be revealed, whereas the foramen magnum was shown to rotate upwards and backwards in relation to the plane of the canal. This implies that the orthocephalization which takes place between 14 and 60 d is caused only by angular changes, and that no apparent changes occur due to changes in head posture.
在生长过程中，由于颅骨各部分以及单个骨头之间的弯曲，大鼠颅骨会大幅变直。这种变直被定义为正颅化。正颅化也可能是由于生长过程中头部姿势的改变引起的，也就是说它可能是“表观的”。为了研究这一现象的意义，对14日龄、30日龄和60日龄雄性大鼠的干燥颅骨进行了X射线摄影，并分别测量了外侧半规管平面与枕骨大孔平面以及蝶骨基底部平面之间的角度。当外侧半规管平面水平放置时，头部被认为处于自然位置。未发现外侧半规管与蝶骨基底部之间的角度有变化，而枕骨大孔相对于半规管平面向上和向后旋转。这意味着14至60日龄之间发生的正颅化仅由角度变化引起，并且由于头部姿势的改变不会出现表观变化。
