Desmond M E
Anat Rec. 1982 Sep;204(1):89-93. doi: 10.1002/ar.1092040112.
Previous studies of both chick and human embryos have shown that the brain enlarges rapidly once the neural tube becomes a closed, fluid-filled system. Prior to such enlargement, the medial walls of the spinal cord appear fused, occluding the lumen. This study describes occlusion of the lumen in terms of its incidence, location along the neuroaxis, time of occurrence, duration of occurrence, and morphology in human embryos. Eighty-two human embryos (stages 9-15) from the Carnegie Collection were analyzed. Occlusion first occurs (and is most prevalent) in stage 11 embryos and is absent in embryos older than stage 13. In all cases examined, the neuroaxis demonstrated uninterrupted occlusion from the level of the third pair of somites to at least the ninth pair (i.e., approximately 60% of the neuroaxis was occluded). The appearance of the occluded neural tube in cross sections is similar to that of a soda straw that has been pinched between one's fingers.
先前对鸡和人类胚胎的研究表明，一旦神经管成为一个封闭的、充满液体的系统，大脑就会迅速增大。在这种增大之前，脊髓的内侧壁似乎融合在一起，堵塞了管腔。本研究从管腔堵塞的发生率、沿神经轴的位置、发生时间、持续时间以及人类胚胎中的形态等方面对其进行了描述。对卡内基藏品中的82个人类胚胎（9-15期）进行了分析。堵塞首先发生在（且最常见于）11期胚胎中，而在13期以上的胚胎中不存在。在所有检查的病例中，神经轴从第三对体节水平到至少第九对体节水平呈现不间断的堵塞（即，大约60%的神经轴被堵塞）。横切面上堵塞的神经管外观类似于被手指挤压过的吸管。
