Department of Otorhinolaryngology, Tottori University, Yonago, Japan.
Anat Rec (Hoboken). 2010 Mar;293(3):438-45. doi: 10.1002/ar.21089.
The aim of this study was to find basic rules governing the morphological development of the typical neurovascular sheath. We carried out histological examination of 15 paraffin-embedded mid-term fetuses at 9-25 weeks of gestation (three fetuses each at 9, 12, 15, 20, and 25 weeks). As the result, the vagus nerve showed a high propensity to change its topographical relationship with the common carotid artery (CCA) during 9-20 weeks of gestation: that is, from a primitive ventral course to a final dorsal course. The adventitia of the great arteries, which was distinct from other fascial structures, became evident by 15 weeks. The carotid sheath appeared at and after 20 weeks: it was clearly separated from the prevertebral lamina of the deep cervical fasciae, but fused with the pretracheal lamina covering the strap muscles. Thus the carotid sheath, as well as the topographical relationships of structures within it, seems to become established much later than the prevertebral and pretracheal laminae of the deep cervical fasciae. However, the adventitia of the cervical great arteries consistently becomes evident much earlier than the sheath, and it seems to be regarded as one of the basic components of the fetal deep cervical fasciae.
本研究旨在探寻典型神经血管鞘形态发育的基本规律。我们对 9-25 孕周的 15 例石蜡包埋中期胎儿进行了组织学检查（每个孕周各 3 例）。结果显示，迷走神经在 9-20 孕周期间与颈总动脉（CCA）的局部关系具有很强的变异性：从原始的腹侧走向最终的背侧。大动脉的外膜在 15 周时与其他筋膜结构明显不同。颈动脉鞘在 20 周时出现：它与深部颈筋膜的椎前板明显分离，但与覆盖颈阔肌的气管前板融合。因此，颈动脉鞘及其内部结构的局部关系似乎比深部颈筋膜的椎前和气管前板晚得多形成。然而，颈总动脉的外膜始终比鞘早出现，它似乎被视为胎儿深部颈筋膜的基本组成部分之一。
