O'Rahilly R, Muller F, Meyer D B
J Anat. 1980 Oct;131(Pt 3):565-75.
The present investigation of the vertebral column at 8 post-ovulatory weeks, the first such study based on precise reconstructions, has revealed 33 or 34 cartilaginous vertebrae arranged in flexion and approximately 20--33 mm in total length. At the end of the embryonic period proper, a typical vertebra, such as TV6, consists of a centrum that is continuous with two neural processes. Pedicles, articular and transverse processes, but no spinous processes, are identifiable. The tips of the neural processes, which are formed by the laminae, are connected by fibrous tissue and resemble the condition of total rachischisis. The union of the laminae, the onset of ossification, and the appearance of articular cavities are characteristic of the early fetal period. The variations encountered within a single developmental stage were noted. They were mostly minor, e.g. the number of coccygeal elements and the extent of the dorsal growth of the neural processes.
本次对排卵后8周脊柱的研究，是基于精确重建的首个此类研究，揭示了33或34块呈屈曲排列的软骨椎骨，总长度约为20 - 33毫米。在胚胎期结束时，一个典型的椎骨，如胸6，由一个椎体和两个神经突组成，椎体是连续的。椎弓根、关节突和横突可辨认，但无棘突。由椎板形成的神经突尖端由纤维组织相连，类似于完全脊柱裂的情况。椎板的联合、骨化的开始以及关节腔的出现是胎儿早期的特征。记录了在单个发育阶段出现的变异。它们大多是轻微的，例如尾骨元素的数量和神经突背侧生长的程度。
