Meninges & Meningeal spaces – Flashcards
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meninges
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are three layers of protective tissue called the dura mater, arachnoid mater, and pia mater that surround the neuraxis
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epidural space
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-space between the dura mater and the periosteum -always exists around spinal cord but usually NOT around the brain because the dura mater fuses with the bony plates of the skull
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dura mater
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most superficial layer and toughest of the three meningeal layers, composed of two layers
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periosteal dura mater
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upper layer of the dura mater -fuses to the inner surface of the bony plates of the cranium -this layer does NOT descend with the spinal cord and therefore is NOT fused to the vertebrae
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Meningeal dura mater
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lower layer of the dura mater -found around both the brain and spinal cord
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superior sagittal sinuses
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formed where the periosteal and meningeal layers separate to form a channel
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venous blood
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collects in and travels through dural sinuses absorbing CSF by osmosis. -The osmotic pressure of the venous blood (due to presence of proteins) is greater than the OP of the CSH
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arachnoid mater
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the middle of the three meningeal layers thin, delicate layer resembling cobwebs just under the dura mater and extending towards the pia mater
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arachnoid villus
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knob-like projections of the arachnoid mater that extend through the dura mater into the superior sagittal sinus -CSF is absorbed through these into the venous blood by osmosis -aka (arachnoid granulations)
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pia mater
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the deepest of the three meningeal layers -it is bound tightly to the surface of the brain and cord
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subarachnoid space
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space between the arachnoid mater and pia mater -always exists around both the brain and spinal cord filled w/ CSF -extends all the way to the level of S2 -a sample of CSF is withdrawn from this space in the lumbar region to test for meningitis during a spinal tap
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subdural space
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space between the dura mater and the arachnoid mater -filled w/ 140-150 ml of CSF -always exsist around the brain but usually not around the spinal cord
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subdural hematoma
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collection/clot of blood between the surface of the brain and dura mater
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falx cerebri
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is a large, crescent-shaped fold of meningeal layer of dura mater that descends vertically in the longitudinal fissure between the cerebral hemispheres
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falx cerebelli
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is a small infolding of the dura in the sagittal plane over the floor of the posterior cranial fossa. It partially separates the two cerebellar hemispheres
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cerebellum
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the part of the brain at the back of the skull in vertebrates. Its function is to coordinate and regulate muscular activity.
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superior sagittal sinus
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is the largest dural venous sinus
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straight sinus
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is one of the main dural venous sinuses -found at the junction between the falx cerebri and the tentorium cerebelli and is triangular in cross section
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transverse sinus
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is one of the dural venous sinuses -drains the superior sagittal sinus the occipital sinus and the straight sinus, and empties into the sigmoid sinus which in turn reaches the jugular bulb.
