On the Trabecular Morphologies and Load Transfer to the Brain

2013 ◽  
Author(s):  
Siavash Hashemi ◽  
Parisa Saboori ◽  
Shahab Mansoor-Baghaei ◽  
Ali M. Sadegh
Keyword(s):  
Human Brain ◽  
Dura Mater ◽  
Subarachnoid Space ◽  
Load Transfer ◽  
Trabecular Architecture ◽  
Pia Mater ◽  
Tree Shape ◽  
External Loads ◽  
The Brain ◽  
Arachnoid Mater

The human brain trabeculae contain strands of collagen tissues connecting the arachnoid to the pia mater. In this paper the mechanotransductions of the external loads to the head passing through different trabecular architectures of the subarachnoid space were investigated. This has been accomplished by creating several local 2-D models consist of skull, dura mater, arachnoid, trabecular architecture and the brain. Different orientations of several architectures of the trabeculae were also analyzed. All models were subjected to the same loading and constraints. The strains in the brain for each model of the architecture and morphology were determined and compared to other corresponding models. It is concluded that the strain in the brain is less where the tree-shape trabeculae are upright, where the branches are attached to the arachnoid mater and the stems are attached to the pia mater. In addition, in the case of other morphologies the strain in the brain is less when the ratio of the trabecular area to the CSF space is less.

Effect of Trabecular Architecture on Transferring Load/Impact to the Brain: A Local Model of Single Trabecula

2011 ◽  
Author(s):  
Parisa Saboori ◽  
Ali Sadegh
Keyword(s):  
Subarachnoid Space ◽  
External Load ◽  
Animal Studies ◽  
Trabecular Architecture ◽  
Local Models ◽  
Pia Mater ◽  
The Impact ◽  
External Loads ◽  
The Brain ◽  
Load Impact

In this paper the mechanotransduction of the external load through the trabeculae in the subarachnoid space (SAS) was investigated. This has been accomplished by employing the results of our animal studies, i.e. the histology and architecture of trabeculae, and by creating local models consist of a trabecula. It is concluded that the trabeculae are mainly configured as an upright tree-like shaped, where the branches are attached to the pia mater and the stems are attached to the arachnoid. The result of the analysis reveal that said configuration of the trabeculae creates less strain in the brain when the head in subjected to external loads, and thereby damps the impact.

scholarly journals An immunohistochemical study of lymphatic elements in the human brain

2021 ◽  
Vol 118 (3) ◽  
pp. e2002574118
Author(s):  
Éva Mezey ◽  
Ildikó Szalayova ◽  
Christopher T. Hogden ◽  
Alexandra Brady ◽  
Ágnes Dósa ◽  
...  
Keyword(s):  
Human Brain ◽  
Dura Mater ◽  
Cranial Nerves ◽  
Lamina Cribrosa ◽  
Brain Parenchyma ◽  
Pia Mater ◽  
Postmortem Human Brain ◽  
Waste Products ◽  
T Cell Migration ◽  
The Brain

Almost 150 papers about brain lymphatics have been published in the last 150 years. Recently, the information in these papers has been synthesized into a picture of central nervous system (CNS) “glymphatics,” but the fine structure of lymphatic elements in the human brain based on imaging specific markers of lymphatic endothelium has not been described. We used LYVE1 and PDPN antibodies to visualize lymphatic marker-positive cells (LMPCs) in postmortem human brain samples, meninges, cavernous sinus (cavum trigeminale), and cranial nerves and bolstered our findings with a VEGFR3 antibody. LMPCs were present in the perivascular space, the walls of small and large arteries and veins, the media of large vessels along smooth muscle cell membranes, and the vascular adventitia. Lymphatic marker staining was detected in the pia mater, in the arachnoid, in venous sinuses, and among the layers of the dura mater. There were many LMPCs in the perineurium and endoneurium of cranial nerves. Soluble waste may move from the brain parenchyma via perivascular and paravascular routes to the closest subarachnoid space and then travel along the dura mater and/or cranial nerves. Particulate waste products travel along the laminae of the dura mater toward the jugular fossa, lamina cribrosa, and perineurium of the cranial nerves to enter the cervical lymphatics. CD3-positive T cells appear to be in close proximity to LMPCs in perivascular/perineural spaces throughout the brain. Both immunostaining and qPCR confirmed the presence of adhesion molecules in the CNS known to be involved in T cell migration.

2. German Retrospect

1889 ◽  
Vol 35 (150) ◽  
pp. 261-271 ◽  
Keyword(s):  
Dura Mater ◽  
Sylvian Fissure ◽  
Pia Mater ◽  
The Brain

S. Beljahow communicated to the Psychiatric Association of St. Petersburg his observations on four brains of senile dements (“Neurologisches Centralblatt,” No. 3, 1887). Three of these subjects were women. The weights of the brains were 1030, 1035, 1080, and 1100 grammes. Their ages ran from 64 to 75 years. The pathological alterations were similar in all the four cases. There was hardening of the cranial bones; in some cases the diploe had entirely disappeared. The dura mater was found united with the cranium; there was also pachymeningitis hæmorrhagica. The pia mater was thickened, and when detached from the cortex brought away a portion of matter with it. The convolutions were slender; the fissures wider than usual; the cortical portion of the brain diminished in thickness; the vessels of the base of the brain, especially the basilar carotids and the arteries of the Sylvian fissure, were sclerosed and their walls in some places calcified.

scholarly journals On the casuistry of progressive paralysis (several cases with acute and prolonged course)

2021 ◽  
Vol XII (2) ◽  
pp. 197-208
Author(s):  
G. A. Dedov
Keyword(s):  
Dura Mater ◽  
Great Difficulty ◽  
Pathological Changes ◽  
Serous Fluid ◽  
Pia Mater ◽  
Internal Organs ◽  
Inner Surface ◽  
Cortical Substance ◽  
The Right ◽  
The Brain

28 / VII. The patient died at 6.30 am. Opening 28 / VII. Great emaciation; stiffness is poorly expressed; on the sacrum and on the right trochanter bedsores. The bones of the cranial vault are thickened, diple is almost absent. Dura mater is spliced ​​in some places with the inner surface of the vault and with the pia mater. The last one is thickened, cloudy (milky stripes), it is removed from the surface of the brain with great difficulty. Brain weight 1397.0; its substance is edematous; the cortical substance is anemic, atrophied; the lateral ventricles are dilated with a large amount of serous fluid. In the internal organs, except for the expansion of the lower lobes of both lungs, no pathological changes were noted.

Evaluation by Fluid/Structure-Interaction Spinal-Cord Simulation of the Effects of Subarachnoid-Space Stenosis on an Adjacent Syrinx

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
C. D. Bertram
Keyword(s):  
Spinal Cord ◽  
Dura Mater ◽  
Subarachnoid Space ◽  
Short Pulse ◽  
Fluid Motion ◽  
Pulse Excitation ◽  
Longitudinal Motion ◽  
Pia Mater ◽  
Bulk Fluid ◽  
Fluid Displacement

A finite-element numerical model was constructed of the spinal cord, pia mater, filum terminale, cerebrospinal fluid in the spinal subarachnoid space (SSS), and dura mater. The cord was hollowed out by a thoracic syrinx of length 140 mm, and the SSS included a stenosis of length 30 mm opposite this syrinx. The stenosis severity was varied from 0% to 90% by area. Pressure pulse excitation was applied to the model either at the cranial end of the SSS, simulating the effect of cranial arterial pulsation, or externally to the abdominal dura mater, simulating the effect of cough. A very short pulse was used to examine wave propagation; a pulse emulating cardiac systole was used to examine the effects of fluid displacement. Additionally, repetitive sinusoidal excitation was applied cranially. Bulk fluid flow past the stenosis gave rise to prominent longitudinal pressure dissociation (“suck”) in the SSS adjacent to the syrinx. However, this did not proportionally increase the longitudinal motion of fluid in the syrinx. The inertia of the fluid in the SSS, together with the compliance of this space, gave a resonance capable of being excited constructively or destructively by cardiac or coughing impulses. The main effect of mild stenosis was to lower the frequency of this resonance; severe stenosis damped out to-and-fro motions after the end of the applied excitation. Syrinx fluid motion indicated the fluid momentum and thus the pressure developed when the fluid was stopped by the end of the syrinx; however, the tearing stress in the local cord material depended also on the instantaneous local SSS pressure and was therefore not well predicted by syrinx fluid motion. Stenosis was also shown to give rise to a one-way valve effect causing raised SSS pressure caudally and slight average cord displacement cranially. The investigation showed that previous qualitative predictions of the effects of suck neglected factors that reduced the extent of the resulting syrinx fluid motion and of the cord tearing stress, which ultimately determines whether the syrinx lengthens.

Optic Nerve Sheath Fenestration—Indications and Techniques

2013 ◽  
Vol 06 (02) ◽  
pp. 125 ◽  
Author(s):  
Nisha Mukherjee ◽  
Mays A El-Dairi ◽  
M Tariq Bhatti ◽  
◽  
◽  
...  
Keyword(s):  
Optic Nerve ◽  
Visual Loss ◽  
Surgical Techniques ◽  
Optic Nerve Sheath ◽  
Pia Mater ◽  
Optic Nerve Sheath Fenestration ◽  
Nerve Sheath ◽  
Indications And Complications ◽  
The Brain ◽  
Arachnoid Mater

The optic nerve is a white matter tract of the brain and its sheath is composed of pia mater, arachnoid mater, and dura mater. The subarachnoid space (SAS) of the optic nerve sheath, which contains cerebrospinal fluid, is contiguous with the SAS of the brain. Elevated intracranial pressure is transmitted to the optic nerve head through the SAS resulting in papilledema. Optic nerve sheath fenestration (ONSF) can be an effective surgical technique to preserve vision in patients with progressive optic neuropathy due to papilledema caused by idiopathic intracranial hypertension (IIH); however, a dreaded complication of ONSF is visual loss. This article will discuss the rationale, indications, and complications of ONSF. A variety of surgical techniques can be employed to perform an ONSF. In particular, the medial transconjuctival approach will be highlighted.

Histology and Trabecular Architecture of the Brain for Modeling of Subarachnoid Space

2010 ◽  
Author(s):  
Parisa Saboori ◽  
Ali Sadegh
Keyword(s):  
Subarachnoid Space ◽  
Impact Load ◽  
Angular Acceleration ◽  
Trabecular Architecture ◽  
Solid Materials ◽  
Complex Architecture ◽  
The Impact ◽  
The Brain

Subarachnoid space (SAS) plays an important role in transferring and or damping the impact load or angular acceleration to the brain (Zoghi Sadegh 2009). Previous investigations have over simplified the complex architecture of the trabeculae of SAS and employed soft solid materials. The goal of this study is to investigate the histology, architecture and mechanotransduction of subarachnoid space and in particular the trabeculae. The results of this study facilitate future modeling of the brain and thereby better understanding of the TBI.

Anatomical relationships of the pia mater to cerebral blood vessels in man

1986 ◽  
Vol 65 (3) ◽  
pp. 316-325 ◽  
Author(s):  
Margaret Hutchings ◽  
Roy O. Weller
Keyword(s):  
Electron Microscopy ◽  
Cerebral Cortex ◽  
Blood Vessels ◽  
Subarachnoid Space ◽  
Blood Cells ◽  
Inflammatory Cells ◽  
Perivascular Spaces ◽  
Pia Mater ◽  
Transmission Electron ◽  
The Brain

✓ Using scanning and transmission electron microscopy and light microscopy, the authors studied the human pia mater and its relationship to the entry of blood vessels into the normal cerebral cortex. The purpose of this investigation was to examine the long-established concept that the subarachnoid space communicates directly with the perivascular spaces of the cerebral cortex. Brains obtained post mortem from subjects with recent subarachnoid hemorrhage (SAH) and purulent leptomeningitis were studied by light microscopy to determine the permeability of the pia mater to red blood cells and inflammatory cells. Scanning electron microscopy showed that the normal pia mater is a flat sheet of cells that is reflected from the surface of the brain to form the outer coating of the meningeal vessels in the subarachnoid space. Transmission electron microscopy confirmed that the cells of the pia mater are joined by junctional complexes and form a continuous sheet that separates the subarachnoid space on one side from the subpial and perivascular spaces on the other. Thus, neither the pia mater nor the subarachnoid space extends into the brain beside blood vessels as they enter the cerebral cortex. The perivascular spaces were, in fact, found to be confluent with the subpial space and not with the subarachnoid space. In cases of recent SAH, red blood cells did not enter the perivascular spaces from the subarachnoid space; neither did India ink injected post mortem into the subarachnoid space pass into the perivascular spaces. The results of these crude tracer studies suggest that the pia mater is an effective barrier to the passage of particulate matter. Histological examination of brains of patients who had died with purulent leptomeningitis showed that inflammatory cells were present in the cortical perivascular spaces and in the contiguous subpial spaces. The presence of a large number of inflammatory cells in the subarachnoid space suggests that inflammatory cells readily penetrate the pia mater that separates the perivascular spaces from the subarachnoid space. The permeability of the pia mater to small molecular weight substances is briefly discussed.

The Effect of the Sulcus Morphology on the Transduction of Impacts to the Brain

2012 ◽  
Author(s):  
Parisa Saboori ◽  
Ali Sadegh
Keyword(s):  
Human Brain ◽  
Brain Injuries ◽  
Fundamental Problem ◽  
Human Head ◽  
Traumatic Brain Injuries ◽  
The Body ◽  
Brain Morphology ◽  
Body Region ◽  
Pia Mater ◽  
The Brain

The human head, being a vulnerable body region, is most frequently involved in traumatic brain injuries (TBI) and life threatening injuries. Accurate modeling of the variability of the brain morphology is a fundamental problem in investigating TBI. Improved computational/mathematical structural models of the brain are needed to help investigators to have a better understanding of the phenomena of different traumatic brain injuries such as concussion. The human brain is the most complex region of the body. There is a very thin membrane known as a pia mater that covers all the surface of the brain. The pia mater follows all the fissure of the brain and covers all the surface of the sulci and gyri. Sulcus is referred to any furrow in the brain. Statistically there are about 72 main sulci in the human brain. Previous FE studies of TBI have ignored sulcus morphology in their modeling and thus, their results could be unreliable. In this paper, the effect of the brain sulcus structure on mechanotransduction of impacts to the brain has been investigated. This was accomplished by using series of parametric studies and comparing the results with the model without sulci. The results of this study reveal that the brain’s strain is reduced in the present of sulcus and gyrus structures. We have hypothesized that the presence of sulcus increases the surface area of the brain thereby decreases the normal and shear strain in the brain. That is, the presence of sulcus and gyrus reduce the transduction of the external load and impacts to the white and gray matters of the brain and thereby reduces the risk of TBI. Ignoring sulci in any FE modeling and analysis of the brain may lead to unreliable results.

scholarly journals First in vivo visualization of the human subarachnoid space and brain cortex via optical coherence tomography

2019 ◽  
Vol 12 ◽  
pp. 175628641984304 ◽  
Author(s):  
Karl Hartmann ◽  
Klaus-Peter Stein ◽  
Belal Neyazi ◽  
Ibrahim Erol Sandalcioglu
Keyword(s):  
Optical Coherence Tomography ◽  
Subarachnoid Space ◽  
Brain Cortex ◽  
Three Dimensional ◽  
Optical Coherence ◽  
Pia Mater ◽  
Anatomical Structures ◽  
Non Invasive ◽  
The Brain

The present work explores optical coherence tomography (OCT) as a suitable in vivo neuroimaging modality of the subarachnoid space (SAS). Patients ( n = 26) with frontolateral craniotomy were recruited. The temporal and frontal arachnoid mater and adjacent anatomical structures were scanned using microscope-integrated three-dimensional OCT, (iOCT). Analysis revealed a detailed depiction of the SAS (76.9%) with delineation of the internal microanatomical structures such as the arachnoid barrier cell membrane (ABCM; 96.2%), trabecular system (50.2%), internal blood vessels (96.2%), pia mater (26.9%) and the brain cortex (96.2%). Orthogonal distance measuring was possible. The SAS showed a mean depth of 570 µm frontotemporal. The ABCM showed a mean depth of 74 µm frontotemporal. These results indicate that OCT provides a dynamic, non-invasive tool for real-time imaging of the SAS and adjacent anatomical structures at micrometer spatial resolution. Further studies are necessary to evaluate the value of OCT during microsurgical procedures.

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