Department of Neurosurgery, Tulane University School of Medicine, New Orleans, LA, USA.
Department of Anatomy, Faculty of Medicine, Khon Kaen, Thailand.
World Neurosurg. 2023 Jul;175:e1182-e1185. doi: 10.1016/j.wneu.2023.04.093. Epub 2023 Apr 28.
The internal jugular vein (IJV) is the pre-eminent outflow of the dural venous sinuses (DVS) in the supine position, while the vertebral venous plexus (VVP) dominates venous outflow in the upright position. Emissary veins can also be an accessory pathway for this venous egress. To our knowledge, alternative dural venous sinus directly drainage via the diploic space has not been previously reported in the literature.
Ten fresh frozen adult cadavers underwent exposure of the basilar venous plexus. The entire plexus, still adhered to the underlying clivus, was removed with its underlying bone and submitted for histological examination following decalcification (Masson Trichrome, 5 μm slices).
All specimens were found to have direct communication between the basilar venous plexus and underlying diploic space of the clivus i.e., no intermediate clival emissary vein. These were concentrated near the midline and were more numerous over the clivus near the junction of the occipital and sphenoid bones. The endothelium of the venous sinus was continuous at the opening into the diploic space and these openings ranged in size from 500 to 750 μm (mean 650 μm).
An improved understanding of the cerebral venous drainage can assist clinicians and surgeons in recognizing normal, pathologic, and variant anatomy in this region. Based on our study, direct venous sinus (DVS) to diploic space drainage offers an additional pathway for venous egress from the intracranium. Therefore, removal of the dura over the clivus during various skull base procedures might be associated with increased venous bleeding from the basilar venous plexus on its deep surface where it interfaces with the clivus.
在仰卧位时，颈内静脉（IJV）是硬脑膜静脉窦（DVS）的主要流出通道，而椎静脉丛（VVP）在直立位时支配静脉流出。交通静脉也可以是这种静脉流出的辅助途径。据我们所知，硬脑膜静脉窦通过板障空间的替代直接引流在文献中尚未有报道。
10 例新鲜冷冻成人尸体进行了基底静脉丛的暴露。整个静脉丛仍然附着在下面的斜坡骨上，与下面的骨一起被切除，并在脱钙后进行组织学检查（Masson 三色，5μm 切片）。
所有标本均发现基底静脉丛与斜坡骨板障之间有直接沟通，即没有中间斜坡交通静脉。这些静脉集中在中线附近，在靠近枕骨和蝶骨交界处的斜坡附近更为密集。静脉窦的内皮在进入板障空间的开口处是连续的，这些开口的大小从 500 到 750μm（平均 650μm）不等。
对脑静脉引流的更好理解可以帮助临床医生和外科医生在该区域识别正常、病理和变异的解剖结构。基于我们的研究，直接静脉窦（DVS）至板障空间引流为颅内静脉流出提供了另一种途径。因此，在各种颅底手术中切除斜坡上的硬脑膜可能会导致其深部与斜坡相界面的基底静脉丛出现更多的静脉出血。
