Cranial Cavity Flashcards Preview

MD1 Neuroscience > Cranial Cavity > Flashcards

Flashcards in Cranial Cavity Deck (40):
1

What are the membranes inside the skull surrounding the brain?

3 meninges:
- Dura mater
- Arachnoid mater
- Pia mater

2

Describe the dura

Outer layer
Tough
Fibrous
Attaches to internal aspect of skull

3

Describe the arachnoid

Intermediate layer
Lines inner surface of dura
More delicate
Still fibrous

4

Describe the pia

Innermost layer
Attached to brain
Very difficult to separate from brain

5

What is the extradural space?

Potential space between skull and dura

6

Where does blood collect when the meningeal arteries rupture?

In extradural space

7

What is the subdural space?

Potential space between dura and arachnoid

8

Where does blood collect with venous bleeding?

In subdural space

9

What is the subarachnoid space?

Real space between arachnoid and pia
Filled with CSF

10

Is there anything between the pia and the brain?

No

11

What are the dural septa?

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

12

Describe the falx cerebri

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

Describe the tentorium cerebelli

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

Describe the falx cerebelli

Small
Comes in posteroinferiorly
Lodges between cerebellar hemispheres

15

Describe the diaphragma sellae

Roof to sella turcica

16

What is the sella turcica?

Small depression in sphenoid bone where pituitary gland sits

17

Describe the structure of the dura

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

What is the dural venous sinus?

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

19

Describe the dural venous sinus

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

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

Venous blood from scalp carrying infection drains into dural venous sinuses

21

Describe the superior sagittal venous sinus

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

22

Describe the inferior sagittal sinus

In inferior aspect of falx cerebri
Between double fold

23

Where does the falx cerebri attach to the tentorium cerebelli?

At inferior margin
Two septa at right angles to each other

24

Describe the straight sinus

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

25

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

Confluence of sinuses
At internal occipital protuberance

26

Describe the transverse sinuses

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

Describe the sigmoid sinus

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

28

Describe the petrosal sinus

Small sinus related to petrous part of temporal bone

29

Describe the cavernous sinus

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

30

What arteries supply the bones and meninges?

Many small meningeal arteries

31

What is the largest and most important meningeal artery?

Middle meningeal artery

32

What artery is the middle meningeal artery of?

Maxillary artery

33

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

Foramen spinosum

34

What are the two branches of the middle meningeal artery?

Anterior
Posterior

35

Which artery grooves the interior aspect of the pterion?

Anterior branch of the middle meningeal artery

36

Where are the meningeal arteries located?

In extradural space
Between dura and skull in little grooves in bone

37

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

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

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

Drill hole in skull

39

What is the cla suck subdural haemorrhage?

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

40

Is it possible for a subdural haemorrhage to never present?

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

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