The Eye and Raised ICP Flashcards

1
Q

what are meninges?

A

protective coverings of the brain and spinal cord

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2
Q

what are the three layers of the meninges?

A

dura mater
arachnoid mater
pia mater

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3
Q

what provides the sensory nerve supply to the dua mater?

A

CN V

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4
Q

what is enclosed in the dura mater?

A

the dural venous sinuses

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5
Q

what are the two layers the dura mater splits into around venous sinuses?

A
periosteal layer (outer)
meningeal layer (inner)
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6
Q

what does the pia mater adhere to?

A

the brain and any vessels entering/leaving

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7
Q

what is found between the arachnoid mater and the pia mater?

A

the subarachnoid space

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8
Q

what is found in the subarachnoid space?

A

CSF

blood vessels

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9
Q

how can the subarachnoid space be accessed clinically and why would this be done?

A

lumbar puncture

to get a CSF sample

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10
Q

where is a lumbar puncture done?

A

L3/4 or L4/5 levels

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11
Q

when does the subarachnoid space end?

A

vertebral level S2

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12
Q

what are the four ventricles of the brain?

A

lateral x 2 (left and right)
third ventricle
fourth ventricle

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13
Q

what secretes CSF?

A

the choroid plexus in the lateral and third ventricles

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14
Q

what connects the third and fourth ventricles?

A

the cerebral aqueduct

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15
Q

how is CSF reabsorbed and where?

A

via arachnoid granulations

into the dural venous sinuses

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16
Q

what is raised ICP?

A

increased pressure in the cranial cavity

17
Q

what causes raised ICP?

A

increased pressure either in the CSF or within the brain itself

18
Q

why is raised ICP a serious emergency?

A

can damage the brain and spinal cord by compressing them

19
Q

what is a common symptom experienced by patients with raised ICP?

A

visual problems

20
Q

what is CN II?

A

the optic nerve

21
Q

what covers CN II?

A

meninges

22
Q

what does the optic nerve being surrounded by meninges mean?

A

increased ICP will be transmitted around the optic nerve = results in papilloedema

23
Q

what is papilloedema?

A

swollen optic discs

24
Q

what are dural septae?

A

folds of dural matter that create septae in the cranial cavity

25
Q

what are the four dural septae?

A

falx cerebri
tentorium cerebelli
falx cerebelli
diaphragma sellae

26
Q

what is the largest dural septa?

A

falx cerebri

27
Q

what does falx cerebri divide?

A

the two cerebral hemispheres

28
Q

what does the tentorium cerebelli divide?

A

the cranial cavity into supratentorial and infratentorial areas

29
Q

what does the falx cerebelli divide?

A

the cerebellum into the right and left halves

30
Q

what does the diaphragma sellae cover?

A

the roof of the pituitary fossa

31
Q

what is CN III?

A

the oculo motor nerve

32
Q

how can raised ICP compress CN III?

A

if the medial temporal lobe herniates through the tentorial notch

33
Q

what is the tentorial notch?

A

the free edge of the tentorium cerebelli where the brainstem exits

34
Q

how does CN III compression present?

A

absent pupillary light reflex
dilated pupil
ptosis
eye turned inferolaterally (out and down)

35
Q

what is CN IV?

A

the trochlear nerve

36
Q

what does damage to CN IV cause?

A

paralysis of the superior oblique muscle