Cranial Cavity Flashcards Preview

MD1 Neuroscience > Cranial Cavity > Flashcards

Flashcards in Cranial Cavity Deck (40)
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1
Q

What are the membranes inside the skull surrounding the brain?

A

3 meninges:

  • Dura mater
  • Arachnoid mater
  • Pia mater
2
Q

Describe the dura

A

Outer layer
Tough
Fibrous
Attaches to internal aspect of skull

3
Q

Describe the arachnoid

A

Intermediate layer
Lines inner surface of dura
More delicate
Still fibrous

4
Q

Describe the pia

A

Innermost layer
Attached to brain
Very difficult to separate from brain

5
Q

What is the extradural space?

A

Potential space between skull and dura

6
Q

Where does blood collect when the meningeal arteries rupture?

A

In extradural space

7
Q

What is the subdural space?

A

Potential space between dura and arachnoid

8
Q

Where does blood collect with venous bleeding?

A

In subdural space

9
Q

What is the subarachnoid space?

A

Real space between arachnoid and pia

Filled with CSF

10
Q

Is there anything between the pia and the brain?

A

No

11
Q

What are the dural septa?

A

Dural partitions that project into cranial cavity
Leaves skull
Lodge in between subdivisions of brain
Stop rotational displacement

12
Q

Describe the falx cerebri

A

Sickle/comma shaped
Lies in midline directly beneath sagittal suture
Partway between two cerebral hemispheres
Free inferior edge
Upper margin attached to skull in midline
Goes posteriorly as far as internal occipital protuberance
Anteriorly plugs into cristagalli of ethmoid bone
In sagittal plane

13
Q

Describe the tentorium cerebelli

A
Tented
Crescent shaped
In horizontal plane
From posterior aspect of skull
Forms roof for posterior cranial fossa
Lodges between cerebral hemispheres above and cerebellum below
Attached edge posteriorly
Free edge anteriorly
14
Q

Describe the falx cerebelli

A

Small
Comes in posteroinferiorly
Lodges between cerebellar hemispheres

15
Q

Describe the diaphragma sellae

A

Roof to sella turcica

16
Q

What is the sella turcica?

A

Small depression in sphenoid bone where pituitary gland sits

17
Q

Describe the structure of the dura

A
Like two layers
- Outer = periosteal
- Inner = meningeal
For most part stuck together
Where septa form
- Outer layer continues to line skull
- Inner layer comes down in two places forming double fold
18
Q

What is the dural venous sinus?

A

Venous pool in little space formed by two layers of dura coming away

19
Q

Describe the dural venous sinus

A
Endothelial lined space
Between outer an inner layer of dura
Filled with venous blood
Receives blood from
- Brain via cerebral veins
- Spongy bone of skull via diploid veins
- Scalp via emissary veins
20
Q

How can infection from the scalp spread into the brain and meninges?

A

Venous blood from scalp carrying infection drains into dural venous sinuses

21
Q

Describe the superior sagittal venous sinus

A

At superior margin of falx cerebri

Gets larger as it extends from anterior to posterior aspect of falx cerebri

22
Q

Describe the inferior sagittal sinus

A

In inferior aspect of falx cerebri

Between double fold

23
Q

Where does the falx cerebri attach to the tentorium cerebelli?

A

At inferior margin

Two septa at right angles to each other

24
Q

Describe the straight sinus

A

Where falx cerebri and tentorium cerebelli join
Here, inferior sagittal sinus straightens out into straight sinus
Runs towards superior sagittal sinus

25
Q

Where do the superior sagittal sinus and the straight sinus meet?

A

Confluence of sinuses

At internal occipital protuberance

26
Q

Describe the transverse sinuses

A

Blood goes either left or right at confluence of sinuses
Moves in root of tentorium cerebelli
Heads all the way around to step between middle and posterior cranial fossae at petrous part of temporal bone

27
Q

Describe the sigmoid sinus

A

Transverse sinus S-shapes down to jugular foramen and beginning of internal jugular vein

28
Q

Describe the petrosal sinus

A

Small sinus related to petrous part of temporal bone

29
Q

Describe the cavernous sinus

A

Either side of body of sphenoid
In split in dura over sphenoid
Major structures move through them

30
Q

What arteries supply the bones and meninges?

A

Many small meningeal arteries

31
Q

What is the largest and most important meningeal artery?

A

Middle meningeal artery

32
Q

What artery is the middle meningeal artery of?

A

Maxillary artery

33
Q

What foramen does the middle meningeal artery go through to reach the inside of the skull?

A

Foramen spinosum

34
Q

What are the two branches of the middle meningeal artery?

A

Anterior

Posterior

35
Q

Which artery grooves the interior aspect of the pterion?

A

Anterior branch of the middle meningeal artery

36
Q

Where are the meningeal arteries located?

A

In extradural space

Between dura and skull in little grooves in bone

37
Q

Why is it a medical emergency when a meningeal artery is torn?

A
Thin flat bone of skull fractures > makes sharp spikes > tears artery > blood in extradural space 
Blood collects
Raises ICP
Herniation and compression of brain stem
Depression of respiratory centres
Respiratory arrest
38
Q

How do you fix the raised ICP when due to an extradural haematoma?

A

Drill hole in skull

39
Q

What is the cla suck subdural haemorrhage?

A

Person falls
Tear at point where cerebral veins enter superior sagittal sinus
Slow ooze of venous blood into subdural space

40
Q

Is it possible for a subdural haemorrhage to never present?

A

Yes
Sometimes found on autopsy
Sometimes calcifies and pits > forms epileptic focus

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