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24 Cards in this Set
- Front
- Back
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Meninges
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Cover and protect the CNS
Protect blood vessels and enclose venous sinuses Contain cerebrospinal fluid (CSF) Form partitions in the skull Brain suspended (mechanically) by folds of membrane attached to skull Causes brain to move with head Brain is floated within skull by cerebrospinal fluid filled spaces inside nervous tissue |
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meninges-three layers
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Three layers
Dura mater Arachnoid mater Pia mater |
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Dura mater –
Periosteal layer – Meningeal layer – |
Dura mater – external thick, dense fibrous (collagen) membrane
Periosteal layer – attached to skull Meningeal layer – close to brain, but doesn't follow contours closely |
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dura mater
Dural septa limit excessive movement of the brain Falx cerebri — Tentorium cerebelli — Falx cerebelli — Diaphragma sellae – |
Dural septa limit excessive movement of the brain
Falx cerebri — in the longitudinal fissure; attached to crista galli Tentorium cerebelli — horizontal dural fold between cerebellum and cerebral hemispheres Falx cerebelli — along the vermis of the cerebellum Diaphragma sellae –covers pituitary gland in the sella turcica |
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dural sinuses
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Formed between periosteal and meningeal layers of dura
Drain blood from brain back to venous system |
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Inferior sagittal sinus
Drains into straight sinus Venous blood flows posteriorly in superior sagittal sinus and straight sinus into confluence of the sinuses To transverse sinuses Continues as sigmoid sinus Empties into internal jugular vein |
Inferior sagittal sinus
Drains into straight sinus Venous blood flows posteriorly in superior sagittal sinus and straight sinus into confluence of the sinuses To transverse sinuses Continues as sigmoid sinus Empties into internal jugular vein |
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cavernous sinus
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Cavernous sinus
Blood from ophthalmic, middle cerebral, and sphenoparietal sinus Drain through: Superior petrosal sinus to sigmoid sinus Inferior petrosal sinus to internal jugular vein |
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Dura is only meninx innervated
Responds to stretch – headache Trigeminal nerve (CN V) responds to stimuli superior to cerebellar tentorium Pain localized in head Greater occipital nerve / Vagus (C1-C3 / CN X) responds to stimuli inferior to cerebellar tentorium Pain localized to back of neck |
Dura is only meninx innervated
Responds to stretch – headache Trigeminal nerve (CN V) responds to stimuli superior to cerebellar tentorium Pain localized in head Greater occipital nerve / Vagus (C1-C3 / CN X) responds to stimuli inferior to cerebellar tentorium Pain localized to back of neck |
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Headache
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Brain is insensitive to pain
Meningeal headache - stretch of dura due to variety of conditions Migrane headache - again stretch dura, but due specifically to increased arterial supply |
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Meningeal headache -
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Meningeal headache - stretch of dura due to variety of conditions
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Migrane headache -
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Migrane headache - again stretch dura, but due specifically to increased arterial supply
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Blood to dura comes from variety of arteries
Middle meningeal – largest – most of lateral surface of cerebral dura Clinically most important Deep to pterion (temple) Injured with blows to head Ophthalmic – anterior dura Occipital and vertebral – posterior dura |
Blood to dura comes from variety of arteries
Middle meningeal – largest – most of lateral surface of cerebral dura Clinically most important Deep to pterion (temple) Injured with blows to head Ophthalmic – anterior dura Occipital and vertebral – posterior dura |
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Middle meningeal –
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Middle meningeal – largest – most of lateral surface of cerebral dura
Clinically most important Deep to pterion (temple) Injured with blows to head |
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Ophthalmic –
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Ophthalmic – anterior dura
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Occipital and vertebral –
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Occipital and vertebral – posterior dura
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arachnoid mater
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Middle layer with weblike extensions
Firmly attached to pia mater via trebeculae Potential space between arachnoid and dura Subdural space Spans sulci and between brain structures to create CSF subarachnoid cisterns Subarachnoid space contains CSF and blood vessels Arachnoid villi/granulations protrude into the dural sinuses and permit CSF reabsorption |
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pia mater
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Layer of delicate vascularized connective tissue that clings tightly to the brain
Abuts layer of astrocytes end feet at surface of CNS |
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blood brain barrier
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Both anatomical and physiological barrier that controls movement of extracellular fluid from general body spaces into the CNS
Mainly formed by the pia mater and the tight junctions between adjacent cells (endothelium and astrocytes) There are regions where there are holes in the blood-brain barrier Around pineal gland and pituitary gland In hypothalamus |
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spinal meninges
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Dura only 1 layer and NOT attached to bone
Epidural space filled with adipose and venous plexus Spinal meningeal dura continuous with cranial meningeal dura Periosteal dura NOT continuous |
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Spinal pia and arachnoid are continuous with craninal arachnoid and pia
Spinal pia attached to arachnoid and through to dura via denticulate ligaments Spinal pia ends as filium terminale with attachment to dura sheath which is attached to sacral vertebrae Lumbar cistern (subarachnoid) in region of spinal nerves only – site of CSF sampling-safest place to sample CSF |
Spinal pia and arachnoid are continuous with craninal arachnoid and pia
Spinal pia attached to arachnoid and through to dura via denticulate ligaments Spinal pia ends as filium terminale with attachment to dura sheath which is attached to sacral vertebrae Lumbar cistern (subarachnoid) in region of spinal nerves only – site of CSF sampling-safest place to sample CSF |
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Lumbar cistern (subarachnoid) in region of spinal nerves only –
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Lumbar cistern (subarachnoid) in region of spinal nerves only – site of CSF sampling-safest place to sample CSF
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Potential spaces between meninges can become real spaces
Epidural - between skull and dura mater Hematomas develop quickly and will be fatal due to confined space and arterial source (from meningeal artery) Usually due to blow to side of head Lens-shaped pool of blood in images - compress brain to opposite side |
Potential spaces between meninges can become real spaces
Epidural - between skull and dura mater Hematomas develop quickly and will be fatal due to confined space and arterial source (from meningeal artery) Usually due to blow to side of head Lens-shaped pool of blood in images - compress brain to opposite side |
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subdural
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Subdural – between dura and arachnoid
Hematomas may develop slowly and neural deficiencies increase over time due to venous tear Tears usually in tributaries to superior sagittal sinus Tearing of cerebral vein as it penetrates the arachnoid and enters dural sinus From rapid acceleration/deceleration – get shearing force due to brain lagging behind Crescent-shaped pool of blood in images |
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Subarachnoid hemorrhage –
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Subarachnoid hemorrhage – between arachnoid and pia
Hematomas develop very quickly and can be fatal Debilitating headache / unconsciousness (venous) Due to sudden halt of head movement Damage to cortical veins draining into sinuses |
