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56 Cards in this Set
- Front
- Back
What are the meingal layers? |
Dura, arachnoid, and Pia mater |
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Describe the Dura Mater |
Outer most later, thicket and toughest layer -Periosteal and meningeal layer |
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Periosteal vs Meningeal layers |
P: Adherent to bony walls of cranium M: Forms reflections -Provides support and determines how the brain is displaced with increased intracranial pressure |
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What is the Tentorium Cerebelli |
Primary fold Lies between cerebrum and cerebellum Spereates cranial cavity into supratentorial and infratentorial comp |
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Falx Cerebri |
Lies within the Longitudinal cerebral fissure. divides supratentorial in two |
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Falx Cerebelli |
Lies in the posterior cranial fossa between the cerebellar hemispheres |
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Disphragma Sellae |
Forms roof of hypophyseal fossa and surrounds the pituitary stalk |
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Where are the dural venous sinuses? |
At the edges of the dural reflections
Main venous drainage channels for the brain Venous sinuses allow for CSF drainage via arachnoid granulations |
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What are the sinuses of the brain?
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Transverse
Superior Sagittal Inferior Sagittal Straight Sinus Occipital sinus Confluens of Sinuses |
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Where is the Transverse sinus
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Margin of Tentorium cerebelli
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Where is the Superior Sagittal sinus?
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Edge of Falx Cerebri. Drains into right Transverse
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Where is the Inferior Sagittal sinus |
Free edge of Falx Cerebri
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Where is the straight sinus?
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Attachment of Falx cerebri and tentorium cerebelli.
Drains into left transverse sinus.
From deep brains structures |
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Where is the occipital sinus
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Attached margin of falx cerebelli
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Where is the Confluens of Sinuses
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Formed by the junction of the straight, superior sagittal, and transverse sinuses.
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Dural Innervation |
Dura is innervated by nociceptive afferents that enter the CNS via branches of the Trigenminal nerve |
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What are meningeal headaches |
Irritation due to infection, hemorrhage and tends to refer pain to the face (supratentoral) Back in the back of the head and nack (infratentoral) |
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Blood supply for the meninges |
Middle meningeal artery - branch of maxillary artery and supplies the dura matter. |
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What is an epidural Hematoma |
Damage to the middle meningeal artery (skull fracture). Can cause the dura to strip away from the bone. |
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Describe the Arachnoid mater |
delicate, avascular, loosely adherent to the inner border cells of the dura |
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What does the arachnoid mater contain? |
Outer cell barrier that seperates CSF and subarachnoid space. Aracnoid trabeculae - fibroblasts that join with the pia mater, help to suspend the brain wthin the cranium. |
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Describe inflammation of the meninges |
Infection often spreading through the subarachnoid space wsith CSF. Can be caused by bacteria, viral, fungal |
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How is CSF altered during infection |
Increased WBC and protein. Glucose concentration may also be altered (dec with bact. meningitis) |
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Meningeal signs of infection? |
Headache, fever, lethargy, stiff neck |
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Describe the Pia Mater |
adherent to the contours of the brain and generally not observed on gross examination. |
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What does the Pia Mater do? |
Pial cells penetrate in to the parenchyma, forming a perivascular space (Virchow-Robin space) May provide communication between extracellular space in parenchyma and suparachnoid space Helps anchor the spinal cord within the subarachnoid space. |
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What happens is a superficial blood vessel ruptures in the subarachnoid space? |
May result in signs related to increased intracranial pressure |
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Where are superficial cerebral veins susceptible to tearing? |
Where they enter the dural sinuses "bridging veins". Blood will collect in the space between the dura and arachnoid mater forming subdural hematoma |
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What are the three areas of the floor of the cranial cavity? |
Anterior, Middle, Posterior cranial fossa |
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What makes up the Anterior cranial fossa? |
Frontal ethmoid and sphenoid bones |
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What is the Crista Galli? |
midline bondy ridge, provides a point of attachment for the falx cerebri |
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What forms the posterior border of the cranial fossa? |
Lesser wing of the sphenoid and sphenoid limbus |
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What is the anterior clinoid process? |
Medial end of the lesser wing of the sphenoid. Forms an attachement point for the free edge of the tentorium cerebelli. |
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Where are the olfactory bulbs? |
Accomodated by the cribiform plate of the ethmoid bone on each side |
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What makess up the middle cranial fossa? |
Sphenoid, temporal, and parietal |
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What are the features of the middle cranial fossa? |
Sella turcica in the midline and deep convacities on each side. Bounded anteriorly by lesser wings of the sphenoid bones and posteriorly by the superior border of the petrous temporal bones |
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What forms the depressions in the middle cranial fossa? |
Greater wing of sphenoid (ant), Squamous temporal and parietal bone (Lat), Petrous temporal bone (pos) |
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Where is the hypophyseal fossa? |
Part of the sella turcica Bounded ant by tuberculum sellae and post by the dorsum sellae |
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Where is the Carotid groove? |
Either side of the sell turcica and marks path of the internal carotid artery through the cavernous sinus |
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Where is the trigeminal depression? |
Behind the foramen lacerum near apex of the petrous temporal bone |
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What is the tegmen tympani? |
Thin ossesou plate that serves the dual purpose of forming the an surface of the petrous temporal bone within the cranial cavity and the roof of the tympanic and mastoid antrum |
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What craddles the temporal lobes |
Laterally located concavities of the middle cranial fossa
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What encapsulates the pituitary gland |
Diaphragma Sella and Hypophyseal fossa |
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What composes the Posterior cranial fossa? |
Sphenoid, occipital, temporal bones |
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What is the internal occipital crest |
descends from the internal occipital protuberance to divide the cerebellar fossa in the midline. The crest provides an attachment site for the falx cerebelli |
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What is the Foramen Magnum |
Large opening in floor of posterior cranial fossa Junction of spinal cord and medulla oblongata |
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What is contained in the posterior cranial fossa |
Cerebellum inbetween the cerebellar fossa of occipital bone Pons and medulla resting on shelf of the clivus. |
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What composes the Clivus |
Posterior part of the sphenodial body to which it is attached and the dorsum sellae |
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What is the tentorial notch |
Free edge of tentorium cerebelli Encircles the midbrain |
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Sign and symptoms of increased ICP |
Headache, Vomitting, drowsiness, cranial nerve signs, coma, death |
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Common causes of ICP |
Tumors hemorrhage and disruption of CSF circulation |
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What surrounds the Optic nerve |
Extensions of the meninges inclduing the subarachnoid space. |
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Increase CSF and venous return |
May slow venous return and interfere with neuronal axoplasmic transport resulting in pailledema (swelling of the optic disc) |
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Where does the oculomotor nerve travel |
exists the midbrain and travels anteriorly to enter the anterior edge of the tentorium cerebelli |
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Where does the abducent nerve travel |
Exits the brainstem in the pos cranial fossa and travels upward to enter the dural covering of the clivus. |
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ICP and Abducent/Oculomotor nerves |
Very susceptible to damage due to ICP as the stretch over infelxible barriers. |