Vilmann H, Moss M L
Gegenbaurs Morphol Jahrb. 1981;127(2):176-87.
The present paper considers the significance of a variety of cranial flexions in the process of orthocephalization of the rat skull between 1 day before birth to 14 days after birth. The study is based on a sample of 95 albino rats divided into 5 age groups (1 day before birth - 0 days - 4 days - 7 days - 14 days after birth), who have been sacrificed and x-rayed with subsequent analysis of the photos obtained. Before x-raying, the rat heads have been treated with AgNO3 to improve the contrast of the bone images on the x-ray photos. In the period studied, the angle between the cranial base and the facial part of the skull becomes considerably more obtuse, i.e. the skull becomes considerably more orthocranial. As compared to the changes that have been shown in 14...60 days old rats, the changes in the early period are much more marked. The cranial vault in the young rats studied, also becomes flatter and more square, due to changes between the individual bones of the vault. This flattening is a significant part of the straightening of the rat skull as a whole, i.e. of the process of orthocephalization. In 14...60 days old rats the simultaneous size increase which primarily takes place in the bones of the facial skull reinforces an impression of marked orthocephalization. In the young rats of the present study, the size increase takes place both in the facial and in the cerebral part of the skull. The result of this leaves an impression of only moderate angular changes, although the changes are much more pronounced than in the older rats.
本文探讨了从出生前1天到出生后14天大鼠颅骨在正颅化过程中各种颅骨弯曲的意义。该研究基于95只白化大鼠的样本，分为5个年龄组（出生前1天 - 0天 - 4天 - 7天 - 出生后14天），这些大鼠被处死后进行X射线检查，并对获得的照片进行后续分析。在进行X射线检查之前，大鼠头部用硝酸银处理，以提高X射线照片上骨骼图像的对比度。在所研究的时期内，颅底与颅骨面部部分之间的角度变得明显更钝，即颅骨变得明显更正颅。与14至60日龄大鼠所显示的变化相比，早期的变化更为明显。在所研究的幼鼠中，由于颅顶各块骨头之间的变化，颅顶也变得更扁平、更呈方形。这种变平是大鼠颅骨整体变直过程（即正颅化过程）的重要组成部分。在14至60日龄大鼠中，主要发生在面颅骨骨骼中的同时性尺寸增加强化了明显正颅化的印象。在本研究的幼鼠中，颅骨的面部和脑部都有尺寸增加。尽管这些变化比成年大鼠更明显，但结果给人的印象只是角度变化适中。
