Recently intriguing results of the research performed on astronauts of the International Space Station have been published. Unexpectedly, in some crew members a stagnant and bidirectional flow in the internal jugular vein was found, and in one of the astronauts this vein seemed to be totally thrombosed. If it actually were the case that in the settings of weightlessness there is a substantial risk of jugular vein thrombosis, any long-term human space missions would be extremely dangerous. Yet, we interpret these findings differently. In our opinion, what has been explained as bidirectional flow, actually represented the flow separation, and what has been described as occluded vein was rather the vein with recirculating and low-velocity flow. In this paper, basing on physical laws governing the flow of fluids, we describe how the flow separation and recirculation can develop in a dilated internal jugular vein, how it can affect cerebral outflow through this vein, why such a phenomenon is more likely in the settings of microgravity and how future research on this topic should be directed.

最近发表了对国际空间站宇航员进行的研究的有趣结果。出乎意料的是，在某些机组人员中，发现颈内静脉停滞和双向流动，而在一名宇航员中，该静脉似乎完全被血栓形成。如果实际上是在失重的情况下存在颈静脉血栓形成的巨大风险，那么任何长期的人类太空飞行任务都将是极其危险的。但是，我们对这些发现的理解不同。在我们看来，被解释为双向流动，实际上代表了流动分离，而被描述为闭塞静脉，则是具有再循环和低速流动的静脉。在本文中，基于控制流体流动的物理定律，