The Subdural Space and Its Linings

Leary, Timothy

doi:10.1001/archneurpsyc.1933.02240100010002

Cited by 30 publications

(10 citation statements)

References 8 publications

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“…This similarity is rather significant as there is good evidence that both membranes are developed from the same ectodermal embryonic tissue, the neural crest. Harvey & Burr (1926), Harvey, Burr & van Campenhout (1933) and Lear & Edwards (1933) It would seem, therefore, that the ectodermal tissues of the entire nervous system, central and peripheral, are separated from the surrounding mesodermal elements by a continuous system of ectodermal sheaths. In this light, the significance of the peripheral nerve sheath becomes more evident.…”

Section: Discussionmentioning

confidence: 99%

Some observations on perfused frog sciatic nerves

Krnjević¹

1954

The Journal of Physiology

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Blair, 1938;Rossel, 1943). This opinion has been challenged repeatedly by Lorente de No in recent years (1947, 1950, 1952), in spite of powerful additional evidence (Feng & Liu, 1949;Rashbass & Rushton, 1949;Lundberg, 1951;Crescitelli, 1951) (1950, 1952) who claims that the presence of the sheath is of great importance for the normal function of the nerve fibres, and that a desheathed nerve is not a proper subject for the study of normal activity. He believes consequently that the delayed blocking action of Na-free and strong K solutions in intact frog nerves demonstrates the indirect connexion between Na and K and nerve conduction, and that the rapid onset of inexcitability shown by desheathed nerves in such solutions is a clear expression of the abnormal condition of the nerve fibres.The purpose of the present experiments was to test the action of Na-free and other solutions introduced into nerves by their blood vessels, thus by-passing the sheath. Under these conditions, there is nothing to suggest that the nerve fibres are in a grossly abnormal state, and a comparison of the behaviour of such perfused nerves with that of control nerves should establish unambiguously whether the sheath is a barrier to diffusion.Vascular perfusion methods have been used in frogs widely for a variety of purposes since the beginning of this century (Verworn, 1900) and the classical frog hind-limb 'Lawen-Trendelenburg' preparation (first described by Cushing,

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Section: Discussionmentioning

confidence: 99%

Some observations on perfused frog sciatic nerves

Krnjević¹

1954

The Journal of Physiology

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“…He described parietal (next to the dura) and visceral arachnoid layers separated by the "arachnoid cavity proper"; this cavity appears to correlate, in general, with the subdural space of other early studies. Building on these data, investigators in the early part of this century offered what, at the time, was considered compelling evidence that a f hid-containing space existed between the dura and arachnoid (Cushing, 1914;Weed, 1914aWeed, ,b, 1916Weed, , 1917aWeed, ,b, 1920Weed, , 1923Weed, , 1938Wegefarth and Weed, 1914;Mallory, 1920;Penfield, 1923Penfield, , 1924; see also Woollard, 1924;Leary and Edwards, 1933).…”

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confidence: 99%

“…The lining on the dural side was described as flattened cells and processes while that on the arachnoid side was either flattened or cuboidal. Leary and Edwards (1933) offered a counterpoint to this view. These authors compared scrapings of the pericardial, pleural, and peritoneal cavities with scrapings of the outer surface of the arachnoid and inner surface of the dura.…”

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confidence: 99%

On the question of a subdural space

1991

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The structure of the meninges, with particular attention to the architecture of the inner portions of the dura mater and the arachnoid mater, has been reviewed in reference to the probable existence of a "subdural" space. The dura is composed of fibroblasts and large amounts of extracellular collagen. The innermost part of the dura is formed by the dural border cell layer. This layer is characterized by flattened cells with sinuous processes, extracellular spaces containing an amorphous material, and the presence of junctions between its cells. The dural border cell layer is continuous with the inner (meningeal) portions of the dura and may be attached to the underlying arachnoid by an occasional cell junction. The arachnoid consists of an outer part, the arachnoid barrier cell layer, and an inner portion, the arachnoid trabeculae which bridge the subarachnoid space. Arachnoid barrier cells are electron-lucent, closely apposed to each other, and joined by many cell junctions; in this layer there is little extracellular space and essentially no intercellular material. Arachnoid trabecular cells cross the subarachnoid space in a random manner, have extracellular collagen associated with their flattened processes, and form structures of variable shapes and sizes. There is no evidence of an intervening space between the arachnoid barrier cell layer and the dural border cell layer that would correlate with what has been called the subdural space. When a tissue space is created in this general area of the meninges it is the result of tissue damage and represents, in most instances, a cleaving open of the dural border cell layer. In this situation, extracellular spaces in the dural border cell layer are enlarged, cell junctions are separated, and it is probable that cell membranes are damaged. A survey of reports describing the morphology of the inner and outer capsule of so-called subdural hematomas in humans reveals that dural border cells are found in both parts of the capsule. Also, experimental infusion of blood into this portion of the meninges in animals frequently dissects open the dural border cell layer. These data support the view that what has been called a subdural hematoma is most frequently a lesion found within the layer formed by dural border cells. It is suggested that the so-called subdural space is not a "potential" space since the creation of a cleft in this area of the meninges is the result of tissue damage. In this respect it shares no similarities with legitimate potential spaces (i.e., serous cavities) found at other locations in the body.(ABSTRACT TRUNCATED AT 400 WORDS)

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“…Leary and Edwards described peeling off the inner layer of dura and found the dural lining largely made up of fibroblasts. 30 These authors thought that the dura was lined by fibroblasts, while the arachnoid was covered by a continuous layer of flattened cells of ectodermal origin. Leary and Edwards wrote, "The formation of the subdural space embryologically is perhaps due to the separation of the surface covered by these cells from a layer of mesenchyme which becomes the inner layer of dura."…”

Section: Subdural Hematoma Anatomymentioning

confidence: 99%

“…Leary and Edwards wrote, "The formation of the subdural space embryologically is perhaps due to the separation of the surface covered by these cells from a layer of mesenchyme which becomes the inner layer of dura." 30 Nabeshima et al evaluated the dura in multiple species. 39 They described the dural inner surface as layers of flattened cells similar to flattened fibroblasts and referred to these as "dural border cells."…”

Section: Subdural Hematoma Anatomymentioning

confidence: 99%

Acute subdural hematoma from bridging vein rupture: a potential mechanism for growth

Miller

Nader

2014

JNS

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Most acute subdural hematomas (ASDHs) develop after rupture of a bridging vein or veins. The anatomy of the bridging vein predisposes to its tearing within the border cell layer of the dura mater. Thus, the subdural hematoma actually forms within the dura. The hematoma grows by continued bleeding into the border cell layer. However, the venous pressure would not be expected to cause a large hematoma. Therefore, some type of mechanism must account for the hematoma's expansion. Cerebral venous pressure (CVP) has been demonstrated in animal models to be slightly higher than intracranial pressure (ICP), and CVP tracks the ICP as pressure variations occur. The elevation of CVP as the ICP increases is thought to result from an increase in outflow resistance of the terminal portion of the bridging veins. This probably results from a Starling resistor model or, less likely, from a muscular sphincter. A hypothesis is derived to explain the mechanism of ASDH enlargement. Tearing of one or more bridging veins causes these vessels to bleed into the dural border cell layer. Subsequent ICP elevation from the ASDH, cerebral swelling, or other cause results in elevation of the CVP by increased outflow resistance in the intact bridging veins. The increased ICP causes further bleeding into the hematoma cavity via the torn bridging veins. Thus, the ASDH enlarges via a positive feedback mechanism. Enlargement of an ASDH would cease as blood within the hematoma cavity coagulates. This would stop the dissection of the dural border cell layer, and pressure within the hematoma cavity would equalize with that in the torn bridging vein or veins.

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The Subdural Space and Its Linings

Cited by 30 publications

References 8 publications

Some observations on perfused frog sciatic nerves

Some observations on perfused frog sciatic nerves

On the question of a subdural space

Acute subdural hematoma from bridging vein rupture: a potential mechanism for growth

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