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Central nervous system
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
The walls of the lateral ventricles and the roof of the third and fourth ventricles are lined with a highly vascular membrane, termed the choroid plexus. This produces CSF from the blood and secretes it into the ventricular system. It passes from the lateral ventricles through foramen of Monro into the third ventricle and through the aqueduct of Sylvius into the fourth ventricle. From the fourth ventricle it passes down the central canal and through the foramen of Magendie and Luschka into the subarachnoid space. CSF passes forwards and laterally over the cerebral hemispheres and is reabsorbed back into the blood stream through arachnoid granulations in the superior sagittal sinus and lateral sinus. The absence of granules or obstruction of the aqueduct (aqueduct stenosis) can result in hydrocephalus.
The Mechanobiology of Aqueous Humor Transport across Schlemm's Canal Endothelium
Published in Jiro Nagatomi, Eno Essien Ebong, Mechanobiology Handbook, 2018
As early as 1914, researchers were drawing analogies between the aqueous humor and CSF outflow pathways [87]. This latter pathway involves CSF drainage through arachnoid granulations, or their microscopic manifestations known as arachnoid villi, which are sites where the arachnoid mater herniates through the dura to bulge into the venus sinuses of the brain [88]. Like Schlemm's canal, arachnoid granulations are lined by a continuous endothelial monolayer containing tight junctions [89], where flow crosses the endothelium in the basal-to-apical direction in response to a pressure drop [89]. Also like Schlemm's canal, the arachnoid granulations function as a one-way valve, allowing efflux from the arachnoid mater but preventing reflux of venous contents into the meninges when the pressure gradient reverses [53,68].
Coup-contrecoup brain injury: fluid–structure interaction simulations
Published in International Journal of Crashworthiness, 2020
The five distinct anatomical structures used in this model are shown in Figure 3. The skull, cerebrum, cerebellum, pituitary gland and brainstem each have unique material properties. The patient-specific model is based on the Digital Imaging and Communications in Medicine (DICOM) images acquired from an online database. Anatomical features missing in this model include the skin, spinal cord, meninges and the arachnoid granulation, Figure 2. When compared to the very short impact impulse time history used in these simulations, the CSF ow in the head can be neglected, too. The CSF flow is relatively slow, 0.05–0.08 m s−1, i.e. during the impact impulse time history the CSF flows by 0.2–0.3 mm. These assumptions also make the presence of the granulations negligible.