Exam #1: Meninges, Ventricles, and CSF Flashcards Preview

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Flashcards in Exam #1: Meninges, Ventricles, and CSF Deck (47)
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1
Q

What three layers of the meningies?

A

Dura mater
Arachnoid mater
Pia mater

2
Q

What are the two layers of the dura mater? What are the major differences between the two layers?

A

Periosteal

  • Forms connective tissue sheaths around the cranial nerves
  • Has a rich vascular supply

Meningeal

  • No vascular supply
  • In intimate contact with the arachnoid mater
3
Q

How does the periosteal dura adhere to the skull?

A

Sharpie’s Fibers

4
Q

Where does the meningeal artery lay in relation to the two layers of the dura?

A

The middle meningeal artery supplies the outer/periosteal layer with blood

5
Q

Which layer of the dura dives into the fissures of the brain? What is the consequence?

A
  • Meningeal layer dives into the fissures of the brain (not the sulci)
  • Separation between the periosteal & meningeal layers forms the dural venous sinuses
6
Q

What is the epidural space?

A

Potential interface between the bone & the periosteal dura

*****I.e. an epidural bleed is between the periosteal dura & bone

7
Q

What is the subdural space?

A

Space between the meningeal dura & the arachnoid mater

8
Q

What type of bleed is associated with an epidural & subdural hematoma?

A
Epidural= arterial 
Subdural= venous
9
Q

What happens when there is a tear in the superior sagital sinus?

A
  • Epidural hematoma
  • “Lens shaped”
  • Crosses both hemispheres
10
Q

In a subdural hematoma, what prevents blood from crossing hemispheres?

A

Falx cerebri

11
Q

What is the shape of a subdural hematoma?

A

“Sickle shaped”

12
Q

What is the falx cerebri?

A

Reflection of the meningeal layer of the dura on itself that separates the right & left cerebral hemispheres

13
Q

What are the attachments of the falx cerebri?

A
  • Crista galli

- Tentorium cerebelli that extends to the internal occipital protuberence

14
Q

What does the tentorium cerebelli separate?

A

This is a horizontal reflection of the meningeal layer of the dura that separates the cerebellum & occipital lobes of the cerebrum

15
Q

What does the falx cerebelli separate?

A

Small reflection of the meningeal layer of the dura that separates the cerebellar hemispheres

16
Q

What is the tentorial notch?

A

Anterior opening between the free edge of the tentorium cerebelli and the clivus for the passage of the brainstem

*****Note that this is also called the tentorial incisure

17
Q

Where are the dural venous sinuses?

A

In the space between the periosteal & meningeal dura

18
Q

What is the superior sagittal sinus?

A

This is the largest dural venous sinus that is contained within the falx cerebri; it ends in the confluence of sinuses posteriorly

19
Q

Review the anatomy of the dural venous sinuses.

A

N/A

20
Q

Clinically, what is important to remember about the sinues?

A

Sinuses do NOT have valves; thus, it is easy for them to transmit infection

21
Q

How does the arachnoid mater appear on the brain? What is important to remember about the arachnoid mater?

A

Clear cling wrap

**Does NOT enter the sulci

22
Q

What are the arachnoid trabeculae?

A

Delicate strands of connective tissue that loosely connect the two innermost layers of the meninges – the arachnoid mater and the pia mater.

23
Q

What is the subarachnoid space?

A

Space between the arachnoid mater & the pia mater; note that arachnoid trabeculae are found within this space

*****This is the space occupied by CSF

24
Q

What are the subarachnoid cisterns?

A

The arachnoid mater does not closely follow the contours of the brain; thus, there are places where a space is created between the pia mater & overlying arachoid mater–these spaces are called “subarachnoid cisterns”

25
Q

What is the interpeduncular cistern?

A

This is the subarachnoid cistern between the two cerebral peduncles

26
Q

What CN emergnes from the interpeduncular cistern?

A

CN III

27
Q

What are the arachnoid villi? What is their function?

A

Specialized evaingations of the arachnoid mater that extend into the lumen of the dura; these help to expunge excess CSF from the brain & dump it into the sinuses

28
Q

What structure produces CSF?

A

Choroid plexus

29
Q

What layer of the meninges is closest to the brain?

A

Pia mater

30
Q

What are the ventricles of the brain?

A

Spaces in the brain that generate CSF

31
Q

How many ventricles are there?

A
  • 2x lateral
  • 3rd
  • 4th
32
Q

Describe the flow of CSF.

A
Lateral ventricles 
Interventricular foramen of monro
3rd ventricles 
Cerebral aqueduct 
4th ventricle
33
Q

What are the different parts of the lateral ventricle?

A

1) Body

2) Four horns

34
Q

What forms the walls of the 3rd ventricle?

A

Thalamus

35
Q

What is the narrowest part of the ventricular system?

A

Cerebral aqueduct

36
Q

Where is the 4th ventricle?

A

Between cerebellum posteriorly & pons/ rostural medualla anteriorly

37
Q

What is the lateral apeture or foramen of Luschka?

A

Lateral opening of the 4th ventricle that open into the subarachnoid space

38
Q

What is the median aperture/ foramen of magendie?

A

This the middle opening of the 4th ventricle that opens into the subarachnoid space

39
Q

What is the function of CSF?

A
  • Support
  • Control of ECF
  • Provides route for neuroactive hormones
40
Q

Should you see RBC in CSF?

A

NO

**Indication of a hemorrhage somewhere

41
Q

What supplies blood to the choroid plexus?

A

asdf

42
Q

Describe how blood is filtered in the choroid plexus to leave CSF.

A

Pressure through tight junctions that function as filter–>CSF= plasma

43
Q

What is the blood brain barrier?

A

Anatomical & physiologic complex that controls movement of substances from general extracellular fluid
- Tight junctions at many levels

44
Q

Where is the TRUE blood brain barrier?

A

Pia mater that contains perivascular glia (astrocytes) that limit the movement of substances

45
Q

What should the physician suspect when a patient complains of fever accompanied by photophobia?

A

Meningitis or encephalitis (infection of the meninges vs. brain parenchyma)

46
Q

Why is stiff neck an important sign of meningitis?

A

Patients want to limit movement of the neck to prevent movement of the meninges

47
Q

What is first line treatment for suspected meningitis?

A

Antibiotics–meningitis confirmed with lumbar puncture (elevated protein & WBC) should be empirically treated with broad-spectrum antibiotics