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56 Cards in this Set

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What are the meingal layers?

Dura, arachnoid, and Pia mater

Describe the Dura Mater

Outer most later, thicket and toughest layer


-Periosteal and meningeal layer

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

What is the Tentorium Cerebelli

Primary fold


Lies between cerebrum and cerebellum


Spereates cranial cavity into supratentorial and infratentorial comp



Falx Cerebri

Lies within the Longitudinal cerebral fissure. divides supratentorial in two

Falx Cerebelli

Lies in the posterior cranial fossa between the cerebellar hemispheres

Disphragma Sellae

Forms roof of hypophyseal fossa and surrounds the pituitary stalk

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

What are the sinuses of the brain?

Transverse


Superior Sagittal


Inferior Sagittal


Straight Sinus


Occipital sinus


Confluens of Sinuses



Where is the Transverse sinus

Margin of Tentorium cerebelli

Where is the Superior Sagittal sinus?

Edge of Falx Cerebri. Drains into right Transverse

Where is the Inferior Sagittal sinus

Free edge of Falx Cerebri

Where is the straight sinus?

Attachment of Falx cerebri and tentorium cerebelli.



Drains into left transverse sinus.





From deep brains structures

Where is the occipital sinus

Attached margin of falx cerebelli

Where is the Confluens of Sinuses

Formed by the junction of the straight, superior sagittal, and transverse sinuses.

Dural Innervation

Dura is innervated by nociceptive afferents that enter the CNS via branches of the Trigenminal nerve

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)

Blood supply for the meninges

Middle meningeal artery - branch of maxillary artery and supplies the dura matter.

What is an epidural Hematoma

Damage to the middle meningeal artery (skull fracture). Can cause the dura to strip away from the bone.

Describe the Arachnoid mater

delicate, avascular, loosely adherent to the inner border cells of the dura

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.

Describe inflammation of the meninges

Infection often spreading through the subarachnoid space wsith CSF.




Can be caused by bacteria, viral, fungal

How is CSF altered during infection

Increased WBC and protein. Glucose concentration may also be altered (dec with bact. meningitis)

Meningeal signs of infection?

Headache, fever, lethargy, stiff neck

Describe the Pia Mater

adherent to the contours of the brain and generally not observed on gross examination.

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.

What happens is a superficial blood vessel ruptures in the subarachnoid space?

May result in signs related to increased intracranial pressure

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

What are the three areas of the floor of the cranial cavity?

Anterior, Middle, Posterior cranial fossa

What makes up the Anterior cranial fossa?

Frontal ethmoid and sphenoid bones

What is the Crista Galli?

midline bondy ridge, provides a point of attachment for the falx cerebri

What forms the posterior border of the cranial fossa?

Lesser wing of the sphenoid and sphenoid limbus

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.

Where are the olfactory bulbs?

Accomodated by the cribiform plate of the ethmoid bone on each side

What makess up the middle cranial fossa?

Sphenoid, temporal, and parietal

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

What forms the depressions in the middle cranial fossa?

Greater wing of sphenoid (ant), Squamous temporal and parietal bone (Lat), Petrous temporal bone (pos)

Where is the hypophyseal fossa?

Part of the sella turcica




Bounded ant by tuberculum sellae and post by the dorsum sellae

Where is the Carotid groove?

Either side of the sell turcica and marks path of the internal carotid artery through the cavernous sinus

Where is the trigeminal depression?

Behind the foramen lacerum near apex of the petrous temporal bone

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

What craddles the temporal lobes

Laterally located concavities of the middle cranial fossa


What encapsulates the pituitary gland

Diaphragma Sella and Hypophyseal fossa

What composes the Posterior cranial fossa?

Sphenoid, occipital, temporal bones

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

What is the Foramen Magnum

Large opening in floor of posterior cranial fossa




Junction of spinal cord and medulla oblongata

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.

What composes the Clivus

Posterior part of the sphenodial body to which it is attached and the dorsum sellae

What is the tentorial notch

Free edge of tentorium cerebelli


Encircles the midbrain

Sign and symptoms of increased ICP

Headache, Vomitting, drowsiness, cranial nerve signs, coma, death

Common causes of ICP

Tumors hemorrhage and disruption of CSF circulation

What surrounds the Optic nerve

Extensions of the meninges inclduing the subarachnoid space.

Increase CSF and venous return

May slow venous return and interfere with neuronal axoplasmic transport resulting in pailledema (swelling of the optic disc)

Where does the oculomotor nerve travel

exists the midbrain and travels anteriorly to enter the anterior edge of the tentorium cerebelli

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.

ICP and Abducent/Oculomotor nerves

Very susceptible to damage due to ICP as the stretch over infelxible barriers.