9: Anatomy - raised intra-cranial pressure Flashcards Preview

Ophthalmology Week 1 2017/18 > 9: Anatomy - raised intra-cranial pressure > Flashcards

Flashcards in 9: Anatomy - raised intra-cranial pressure Deck (51)
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1

What does raised intra-cranial pressure mean?

Increase in pressure within the cranial cavity

2

What can cause an increase in intra-cranial pressure?

Brain tumours

Head injury

Hydrocephalus

Meningitis

Stroke

3

A raised ICP causes damage to what CNS structures?

Brain

Spinal cord

4

What is the Monro-Kellie hypothesis?

The volumes of the brain, blood and CSF exist in equilibrium

An increase in one volume causes a DECREASE in the volumes of the others to compensate

So a brain tumour decreases the volume of the blood and CSF and also causes an increase in intracranial pressure (pressure increases as volume decreases)

5

What symptoms do people with a raised ICP tend to have?

Headache

Visual disturbance

blurry vision, double vision, loss of vision, papilloedema, pupillary changes

6

What is diplopia?

Double vision

7

The optic nerve arises from which structure of the brain?

Diencephalon

(thalamus + hypothalamus)

8

Which space is the optic nerve found in?

Subarachnoid space

9

Name the layers of the CNS from outer to inner.

Dura mater (outer)

Arachnoid mater

Pia mater (inner)

10

Between which layers of the CNS is the subarachnoid space found?

Arachnoid mater

Pia mater

11

What fills the subarachnoid space?

Cerebrospinal fluid (CSF)

12

What does CSF do?

Nourishes the brain and removes toxins

13

Once the CSF has circulated in the subarachnoid space, where does it drain?

Dural venous sinuses

14

What structures in the arachnoid mater allow CSF to drain into the dural venous sinuses?

Arachnoid granulations

spaces which allow CSF to drain into venous circulation

15

Which important artery, supplying the brain, is found in the subarachnoid space?

Circle of Willis

16

At which level does the spinal cord end?

At which level does the subarachnoid space end?

L2

S2

17

What can be taken from the subarachnoid space to diagnose CNS diseases?

What is this procedure called?

CSF

Lumbar puncture

18

At which levels can a lumbar puncture be performed?

Why are these areas safe?

L3/4

L4/5

Subarachnoid space but no spinal cord (cauda equina instead, which is much harder to damage)

19

How much CSF circulates in the subarachnoid space at any one time?

500 ml

20

Where is CSF produced?

Choroid plexus of the lateral, third and fourth ventricles

21

CSF drains from the subarachnoid space via the ___ venous sinus, through ___ ___.

dural venous sinus

via arachnoid granulations

22

What secretes CSF?

Where is it found?

Choroid plexus

Lateral, third and fourth ventricles

23

The lateral ventricles are found on the right and left sides of the brain.

Where is the third ventricle found?

Midline

24

Which structure connects the third and fourth ventricles?

Cerebral aqueduct

25

The cerebral aqueduct connects which structures of the brain?

Third ventricle

Fourth ventricle

26

Most CSF passes from the fourth ventricle to the ___ ___.

subarachnoid space

27

Most CSF passes from the fourth ventricle to the subarachnoid space?

Where does the rest of it go?

Central canal

28

Where does CSF circulate once it has passed through the fourth ventricle?

Where is it then reabsorbed?

Subarachnoid space

Central canal

Dural venous sinuses

29

Where does the central canal go?

Spinal cord

Cauda equina

This is why you can get CSF from a lumbar puncture

30

The dura, arachnoid and pia maters are known as ___.

meninges

i.e the lining of the CNS