L2 - Blood supply and Meninges Flashcards Preview

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Flashcards in L2 - Blood supply and Meninges Deck (87)
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1
Q

what are the order of meninges from brain towards skull?

A

(brain) pia arachnoid dura (skull)

2
Q

which meningeal layer can be described as a tough fibrous membrane?

A

dura

3
Q

which meningeal layer can be described as a soft translucent membrane?

A

arachnoid

4
Q

where is the subdural space?

A

space between arachnoid and dura/below the dura (very thin)

5
Q

falx cerebri and tentorium cerebelli are extensions of which meninges layer?

A

dura

6
Q

what is the name of extension of dura matter that forms a partition between the right and left hemispheres?

A

falx cerebri

7
Q

which meningeal layer can be described as microscopically thin, delicate membrane?

A

pia

8
Q

which meningeal layer is tightly adhered to the surface of the brain, following all cavities?

A

pia

9
Q

what is considered a real space? Give examples.

A

a space that normal exists - subarachnoid space in the skull and spine - epidural space in the spine

10
Q

what is considered a potential space? Give examples.

A

not a space - but can become a space in pathological conditions (eg brain bleed) - epidural space in the skull - subdural space in the spine and skull

11
Q

is the epidural space, real or potential?

A

potential in the skull real in the spine

12
Q

what are the real spaces in the skull?

A

subarachnoid space

13
Q

what are the real spaces in the spine?

A

epidural space subarachnoid space

14
Q

what are the potential spaces in the skull?

A

epidural space subdural space

15
Q

what are the potential spaces in the spine?

A

subdural space

16
Q

is the subdural space, real or potential?

A

potential

17
Q

is the subarachnoid space, real or potential?

A

real

18
Q

what is the blood supply of the dura matter?

A

middle meningeal artery

19
Q

what are the twi layers if the dura?

A

outer layer adhered to skull: periosteal inner layer which forms falx cerebral: meningeal

20
Q

the two layers of the dura matter are tightly fused together except for where?

A

dural venous sinuses various infoldings

21
Q

where is the middle meningeal artery? Why is it prone to injury in this position?

A
  • lies below pterion (region where the frontal, parietal, temporal, and sphenoid bones join together. It is located on the side of the skull, just behind the temple.) - most fragile part of the skull and so if it fractures/breaks = middle meningeal artery bleeds
22
Q

where does venous blood of the brain drain?

A

into dural sinuses (e.g superior sagittal sinus) and then into the internal jugular vein

23
Q

where will you find the falx cerebri dural folding?

A

between cerebral hemispheres

24
Q

where will you find the tentorium cerebelli dural folding?

A

between occipital lobes and cerebellum

25
Q

where will you find the falx cerebelli dural folding?

A

between cerebellar hemispheres

26
Q

what is the function of dural infoldings? (e.g falx cerebri)

A

act as shelves to stabilise brain

27
Q

where are the venous (dural) sinuses located?

A

within the dural inholdings

28
Q

what is the function of the venous (dural) sinuses?

A

they receive venous blood from the brain and drain into the internal jugular vein

29
Q

what do superficial veins of the brain drain into?

A

superior sagittal sinus

30
Q

what do deep veins of the brain drain into?

A

internal cerebral veins

31
Q

what do internal cerebral veins of the brain drain into?

A

great vein (of Galen)

32
Q

what does the great vein (of Galen) drain into?

A

straight sinus

33
Q

what does the straight sinus and superior sagittal sinus drain into?

A

confluence of sinuses which drains into the transverse sinuses

34
Q

what does the transverse sinus drain into?

A

sigmoid sinus

35
Q

what does the sigmoid sinus drain into?

A

internal jugular vein

36
Q

what percentage of oxygen consumption does the brain use?

A

20% (high)

37
Q

what condition is a persistent neurological deficit of vascular origin?

A

stroke

38
Q

what are the two arteries that supply the brain?

A

vertebral artery (posteriorly) internal carotid (anteriorly)

39
Q

the vertebral artery is a branch of what vessel?

A

subclavian artery

40
Q

where does the vertebral artery enter the skull?

A

foramen magnum

41
Q

where do the two vertebral arteries join?

A

two pairs of VA join at the basilar artery at the base of the brain stem

42
Q

The internal carotid artery is a branch of what vessel?

A

common carotid artery

43
Q

the common carotid artery bifurcates into internal and external carotid arteries, what do each arteries supply?

A

internal supplies brain external supplies face, scalp, neck

44
Q

where does the internal carotid artery enter the skull?

A

carotid canals NB: and passes OVER (not through) foramen lacerum

45
Q

the carotid canal is a boney feature, what is the clinical relevance of this?

A

If the bone was to fracture, the fractured bone would puncture the ICA

46
Q

in the ventral brainstem how many arteries supply the cerebellar?

A

3 pairs (6 arteries) - Post. Inf. Cerebellar - Ant. Inf. Cerebellar - Sup. Cerebellar

47
Q

in the ventral brainstem how many arteries supply the cerebrum?

A

3 pairs (6 arteries) - Post. Cerebral - Middle Cerebral - Ant. Cerebral

48
Q

what are the branches of the vertebral artery?

A
  • anterior spinal (unpaired) - posterior spinal (paired) - inf. post. cerebellar arteries (PICA)
49
Q

the basilar artery is formed by the joining of which two arteries?

A

two vertebral arteries

50
Q

the anterior spinal artery is formed by the joining of which two arteries?

A

formed by *branches* from both vertebral arteries

51
Q

what are the branches of the basilar artery?

A
  • anterior inferior cerebellar arteries (AICA) - pontine arteries - superior cerebellar arteries - posterior cerebral arteries
52
Q

what are the branches of the internal carotid?

A
  • middle cerebral artery - anterior cerebral artery
53
Q

which artery runs lateral to the optic chiasm?

A

internal carotid artery

54
Q

what forms the vertebrobasilar system?

A

vertebral and basilar arteries

55
Q

what does the vertebrobasilar system supply?

A

cerebellum and brain stem

56
Q

what causes locked in syndrome?

A

pontine arteries damage causing lack of blood supply to the pons

57
Q

why is eye movement possible in locked in syndrome but no other movement is?

A

Eye movement is possible as the oculomotor nerve is above this blood supply

58
Q

why does pontine arteries damage lead to locked in syndrome?

A

Pons contain descending motor fibres for movement, which are supplied by the blood vessel running aside them.

59
Q

what interconnects the internal carotid and vertebrobasilar system?

A

arterial circle of willis

60
Q

what artery system surrounds the optic chiasm and hypothalamus?

A

arterial circle of willis

61
Q

what is the function of the arterial circle of willis?

A

allows collateral circulation – if an artery is blocked, blood can still get through

62
Q

What is a berry aneurysm?

A

abnormal dilations around the circle of willis or at points of arterial branching in the brain

63
Q

what is a saccular aneurysm?

A

which is sac-like dilation on a weak part of the arterial wall. (a berry aneurysm is the most common type of saccular aneurysm)

64
Q

what happens if a berry aneurysm ruptures?

A

allows blood to enter the subarachnoid space = sub-arachnoid haemorrhage

65
Q

what does the anterior cerebral artery (ACA) supply?

A
  • superior and medial areas of frontal and parietal lobes - corpus callosum
66
Q

what does the medial cerebral artery (MCA) supply?

A
  • lateral areas of frontal, temporal and parietal lobes
67
Q

what does the posterior cerebral artery (PCA) supply?

A
  • occipital lobe - inferior and medial surface of temporal lobe
68
Q

what cortical area does the ACA supply?

A

motor and sensory cortices for the lower limb

69
Q

what cortical area does the MCA supply?

A

primary motor and sensory cortices for the whole body (excluding lower limb) and the auditory cortex

70
Q

what cortical area does the PCA supply?

A

the visual cortex

71
Q

which artery supplies the visual cortex?

A

PCA

72
Q

which artery supplies the auditory cortex?

A

MCA

73
Q

which artery supplies the primary motor and sensory cortices for the whole body (except the lower limb)?

A

MCA

74
Q

which artery supplies the motor and sensory cortices of the lower limb?

A

ACA

75
Q

what do deep/perforating arteries off the arterial circle of willis supply?

A

structures inside hemisphere (deep nuclei) - deep grey matter - internal capsule

76
Q

what are striate arteries?

A

arise from the middle cerebral artery and supply deep structures in the cerebrum, including the internal capsule (deep/perforating arteries)

77
Q

what causes an epidural haemorrhage?

A

torn meningeal artery

78
Q

how would a epidural haemorrhage present on an MRI?

A

hemispheres pushed away from the skull

79
Q

what causes a subdural haemorrhage?

A

torn briding veins

80
Q

How would a subdural haemorrhage present on an MRI?

A

dura still applied to the skull but the hemispheres are squished = ventricles pushed away

81
Q

what causes a subarachnoid haemorrhage?

A

torn cerebral arteries

82
Q

how would a subarachnoid haemorrhage present on an MRI?

A

bleeding in the grooves of the brain itself

83
Q

what type of haemorrhage is shown here, and what causes it?

A

epidural haemorrhage

caused by torn meningeal arteries

84
Q

what type of haemorrhage is shown here, and what causes it?

A

subdural haemorrhage

torn bridging veins

85
Q
A
86
Q

what type of haemorrhage is shown here, and what causes it?

A

subarachnoid haemorrhage

torn cerebral arteries

87
Q

watershed areas of the brain are more susceptible to what?

A

ischaemia (watershed stroke)