Frederickson R G
Department of Basic Sciences, Bastyr College, Seattle, Washington.
Anat Rec. 1991 May;230(1):38-51. doi: 10.1002/ar.1092300105.
The subdural region within the cranial meninges is examined in guinea pigs by electron microscopy. The fine structures of the arachnoid membrane and dura are described separately in specimens that have been isolated from each other during removal from the cranial cavity. In addition, the fine structure of the intact dura-arachnoid is described, where the subdural space would be present in an undisrupted state. Lastly, the inner surface of the dura and the outer surface of the arachnoid membrane are examined at the point of separation between the two specimens where the dura is reflected from the arachnoid by experimental dissection. From these observations morphologic criteria are established for identifying the constituents and boundaries of the subdural space and for explaining mechanisms in the histogenetic process of "opening" or enlarging this space. The morphologic identity of the classic subdural space is reinterpreted in light of the findings. The subdural space, traditionally described as a fluid-filled potential cavity existing in an extracellular compartment, is not apparent in the guinea pig. Instead, fragile cells designated as light cells occupy the compartment between the dura and arachnoid, with very little extracellular space available. Experimental opening of the subdural space occurs, significantly, along pathways extending by fracture through the cytoplasm and intercellular separation of these light cells rather than by enlargement of a preexisting mesothelial-lined intercellular space between these cells and the true arachnoid cells. Cytoplasmic fine structure of light cells suggests a close kinship with cells in the meningeal layer of the dura. The functional significance of the light cells and their possible role in subdural hematomas is discussed.
通过电子显微镜对豚鼠颅脑膜内的硬膜下区域进行检查。在从颅腔取出过程中彼此分离的标本中，分别描述蛛网膜和硬脑膜的精细结构。此外，还描述了完整的硬脑膜 - 蛛网膜的精细结构，其中硬膜下间隙处于未受破坏的状态。最后，在通过实验解剖使硬脑膜从蛛网膜反折的两个标本分离点处，检查硬脑膜的内表面和蛛网膜的外表面。根据这些观察结果，建立了形态学标准，用于识别硬膜下间隙的组成成分和边界，并解释该间隙“开放”或扩大的组织发生过程中的机制。根据这些发现，对经典硬膜下间隙的形态学特征进行了重新解释。传统上被描述为存在于细胞外间隙中的充满液体的潜在腔隙的硬膜下间隙，在豚鼠中并不明显。相反，被称为亮细胞的脆弱细胞占据了硬脑膜和蛛网膜之间的间隙，细胞外空间非常小。值得注意的是，硬膜下间隙的实验性开放沿着通过这些亮细胞的细胞质断裂和细胞间分离而延伸的途径发生，而不是通过扩大这些细胞与真正蛛网膜细胞之间预先存在的间皮衬里细胞间隙。亮细胞的细胞质精细结构表明其与硬脑膜脑膜层中的细胞有密切的亲缘关系。讨论了亮细胞的功能意义及其在硬膜下血肿中的可能作用。
