Reina M A, López García A, de Andrés J A, Villanueva M C, Cortés L
Servicio de Anestesiología, Hospital General de Móstoles, Madrid.
Rev Esp Anestesiol Reanim. 1998 Nov;45(9):367-76.
A potential space between the dura mater and the arachnoides is thought to exist, occupied by a serous fluid and called the subdural space. Recent studies may change this classical concept, however. The dura-arachnoid complex from the epidural to the arachnoid space is formed by morphologically distinct layers: the dura mater, the subdural compartment and the arachnoid mater, which are made up of different cell types. The dura mater consists of greater and lesser laminae formed mainly of collagen fibers aligned differently. The subdural compartment is formed by a number of so-called "neurothelial cells", which are in close contact with the inner dural layers. These cells are flat and have long interlaced branches. The arachnoides are made of cells grouped in three different layers. The outer layer is the "barrier arachnoid layer". Located just inside the anterior cell plane, this layer is made of less flattened cells that form an epithelial-type tissue, with complex cell-cell junctures surrounded by collagen fibers. The middle layer is the reticular arachnoid, composed of irregularly interlaced cells alternating with collagen fibers and intercellular gaps of varying sizes. The innermost layer, the trabecular arachnoid, is in direct contact with the subarachnoid space. The cells of this layer form strands that contribute to the weblike pattern found in the subarachnoid space. Recently, special techniques for fixing and preparing samples, preserving in situ the anatomical relations between the arachnoides and the dura mater, have allowed us to examine the normal configuration of the subdural space. All samples examined revealed the presence of a cellular plane between the dura mater and the arachnoides, with no evidence of the classically described space. The zone of least resistance in the dura-arachnoid complex was the subdural compartment, which could be torn mainly along intercellular spaces, though cell rupture was also observed, affecting the cytoplasmic membranes of adjacent cells. The subdural space is opened by tearing the subdural compartment between neurothelial cells alongside the collagen fibers of the dura mater. Such a tear can be caused mechanically by injecting air or contrast media, which exert pressure on a laminar structure that tends to separate because it is weaker than neighboring ones.
硬脑膜和蛛网膜之间被认为存在一个潜在间隙，其中充满浆液，称为硬膜下间隙。然而，最近的研究可能会改变这一经典概念。从硬膜外间隙到蛛网膜下腔的硬脑膜 - 蛛网膜复合体由形态上不同的层次组成：硬脑膜、硬膜下腔隙和蛛网膜，它们由不同类型的细胞构成。硬脑膜由主要由排列方式不同的胶原纤维形成的大、小薄片组成。硬膜下腔隙由一些所谓的“神经上皮细胞”形成，这些细胞与硬脑膜内层紧密接触。这些细胞扁平，具有长的交错分支。蛛网膜由分为三层的细胞组成。外层是“屏障蛛网膜层”。该层位于前细胞平面内侧，由不太扁平的细胞组成，形成上皮样组织，具有被胶原纤维包围的复杂细胞间连接。中间层是网状蛛网膜，由不规则交错的细胞与胶原纤维以及大小不一的细胞间隙交替组成。最内层是小梁蛛网膜，与蛛网膜下腔直接接触。该层细胞形成条索，构成蛛网膜下腔中发现的网状结构。最近，用于固定和制备样本、原位保留蛛网膜和硬脑膜之间解剖关系的特殊技术，使我们能够研究硬膜下间隙的正常结构。所有检查的样本都显示在硬脑膜和蛛网膜之间存在一个细胞平面，没有经典描述的间隙的证据。硬脑膜 - 蛛网膜复合体中阻力最小的区域是硬膜下腔隙，它主要可沿细胞间隙撕裂，不过也观察到细胞破裂，影响相邻细胞的细胞质膜。通过撕开神经上皮细胞之间沿硬脑膜胶原纤维的硬膜下腔隙来打开硬膜下间隙。这种撕裂可由注入空气或造影剂机械性地引起，它们对层状结构施加压力，该层状结构因比相邻结构弱而易于分离。
