Cranial cavity Flashcards Preview

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Flashcards in Cranial cavity Deck (47):
1

Describe the three layers of the meninges?

Dura mater: outer, tough, fibrous

Arachnoid mater: More delicate, fibrous

Pia mater: Thin layer

2

What are each of the three layers of the meninges connected to?

Dura mater: Attached to skull
Arachnoid mater: Lines inner of dura

Pia mater: Lines brain tissue

3

Describe the spaces created by each of the three meninges?

Epidural space: between dura and skull, potential space

Subdural space: between dura and arachnoid, potential space

Subarachnoid space: between arachnoid and pia, occupied by CSF

4

What can accumulate in the epidural space and when?

Blood collects here when meningeal artery ruptures

5

What occupies the subarachnoid space?

CSF

6

What can accumulate in the subdural space and when?

Blood collects here as a result of venous bleeding

7

List the dural petitions that project into the cranial cavity?

Falx cerebri

Tentorium cerebelli

Falx cerebelli

Diaphragma sellae

8

How far into the brain do the dural petitions project into the cranial cavity?

Not all the way; don't cut the brain into component parts

9

What is the purpose of the dural petitions?

Lodge into the brain partway and restrict rotatory displacement of the brain

10

Describe the shape of the falx cerebri?

Sickle shaped

11

Where does the falx cerebri lie?

In midline between the two hemispheres

12

Describe the attachments of the falx cerebri?

Attaches to inside of skull, immediately along line of sagittal suture Pegs to crista galli anteriorly Attaches posteriorly to internal aspect of occipital protuberance

13

Describe the shape of the tentorium cerebelli?

Crescent shaped, tented upwards

14

Where does the tentorium cerebelli lie?

Roofs over posterior cranial fossa, between cerebral hemispheres above and cerebllum below

15

Where does the falx cerebelli lie?

Between cerebellar hemispheres, beneatch tentorium cerebelli

16

Describe the orientation of the falx cerebelli?

Vertical

17

Where does the diaphragma sellae lie?

Roofs over the sella turcica (pituitary) Lines internal aspect of sphenoid bone and goes across pit

18

How are the projections of the meninges formed?

Dura is a double layered structure; layers are usually stuck together Projections are formed when the inner layer separates from the outer layer, and meets with the inner layer from the other side

19

Where do the veins that drain the brain eventually end up?

Dural venous sinuses

20

Describe the structure of the dural venous sinuses?

Endothelial lined spaces Between inner and outer layer of dura when they come apart to form projections Walls are dura

21

Where do the dural venous sinuses lie in relation to the dural layers?

Between inner and outer layer of dura when they come apart to form projections

22

What do the dural venous sinuses receive?

Veins draining the brain

Diploic veins

Emissary veins

23

What do diploic veins drain?

The diploie (spongy bone)

24

What do emissary veins drain?

Scalp

25

Why are scalp wounds treated with caution?

Any infection here can cause meningitis, as it is a very short trip to encephalitis, due to the venous communications

26

What are the major dural venous sinuses?

Superior sagittal sinus

Inferior sagittal sinus

Straight sinus

Transverse sinus

Sigmoid sinus

Cavernous sinus

A image thumb
27

What is the confluence of sinuses?

Point where the superior and straight sinuses meet

28

How is the straight sinus formed?

Where the inferior saggital sinus meets the Great cerebral vein

29

Where does the transverse sinus run?

In the root of the attachment of the tentorium cerebelli

30

What happens at the point of confluence?

Sometimes venous blood mixes, other times it doesn't 

31

Where does the sigmoid sinus begin?

At the point where the tentorium meets the petrous part of the temporal bone 

Transverse sinus becomes sigmoid sinus

32

Describe the course of the sigmoid sinus?

Snakes down from tentorium cerebelli in an s-shaped fashion towards the jugular foramen

33

What does the sigmoid sinus exit the jugular foramen as?

Internal jugular vein

34

Where does the cavernous sinus lie?

Either side of body of sphenoid

35

What is important about the cavernous sinus?

Important structures run through it to access their foraminae and exit the skull

36

How is the cavernous sinus different to the other dural venous sinuses?

It is not associated with any dural septa

37

Which is the most important meningeal artery?

Middle meningeal artery

38

What do the meningeal arteries supply?

Bone and meninges of skull

39

What is the middle meningeal artery a branch of?

Maxillary artery

40

How does the middle meningeal artery enter the skull?

Foramen spinosum

41

What happens to the middle meningeal artery after it branches from the maxillary artery?

Divides into anterior and posterior divisions, which groove the bone

42

Where does the medial meningeal artery liein relation to the meninges?

In the extradural space

43

What is the outcome of a tear in the middle meningeal artery?

Extradural haemorrhage

44

Why is an extradural haemorrhage due to a tear in the MMA so dangerous?

Pulsing blood from the artery

With every pulse, more blood gathers

No give in skull > pressure builds quickly 

45

Where do the superior cerebral veins drain into?

Superior sagittal sinus

46

What is the most common cause of a subdural haemorrhage?

Tearing of veins at the point where they enter the superior sagittal sinus after a fall or head trauma

47

Why is a subdural haemorrhage due to a tear in the superior cerebral veins less dangerous than an extradural haemrrhage due to a tear in the MMA?

Much lower pressure blood