Clinically Relevant Anatomy of Space Occupying Lesions Flashcards

1
Q

Monro Kellie hypothesis

A
  • -Cranial compartment is incompressible and volume inside cranium is fixed
  • -Cranium and its constituents create a state of volume equilibrium, such that an increase in the volume of one constituent must be compensated for by a decrease in the volume of another
  • -The principle buffers to increased volume are CSF and blood volume to a lesser extent
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2
Q

give an example of an acute and subacute expanding intracranial pathology

A
  • acute - bleed
  • subacute - tumour
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3
Q

5 layers of scalp - outside to in

A
  • Skin
  • Connective tissue
  • Aponeurosis
  • Loose connective tissue
  • Pericranium
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4
Q

aponeurosis layer

A

tendon layer between frontalis and occipitalis muscles

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5
Q

why do scalp lacerations bleed excessively

A

scalp arteries form a rich anastomotic network

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6
Q

which layer are the scalp arteries found in

A

Connective tissue layer

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7
Q

which arteries form the anastomotic network in the scalp

A

internal and external carotid

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8
Q

what is the pericranium

A

periosteum enveloping the skull (outer membrane of bone that is responsible for bone formation)

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9
Q

which types of joints are sutures, and what is their purpose

A

fibrous, to prevent cracks spreading between different skull bones

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10
Q

why is the pterion a disadvantage

A
  • thinnest part of skull (frontal, temporal, parietal and sphenoid)
  • directly above middle meningeal artery
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11
Q
A
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12
Q

which bone is the carotid canal found in,and what goes through it

A

temporal bone, internal carotid artery

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13
Q

what gives rise to the pain of meningitis

A

stretching of the dura mater

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14
Q

nerve supply to dura mater

A

sensory supply from CN V

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15
Q

describe the structure of the dura mater

A
  • 2 layers: outer periosteal and meningeal
    • in parts these are close together
    • in parts there are dural venous sinuses between them
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16
Q

diaphragm sellae

A

sheet of dura mater over the pituitary fossa, has a hole to allow the pituitary stalk through

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17
Q

tentorium cerebelli

A

dura mater sheet over the cerebellum, separating cerebral hemispheres from cerebellum

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18
Q

where does the tentorium cerebelli attach

A

to the ridges of the petrous temporal bones

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19
Q

falx cerebri

A
  • midline dura mater sheet
  • separates the right and left cerebral hemispheres
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20
Q

attachments of the falx cerebri

A
  • crista galli of ethmoid bone anteriorly
  • internal aspect of sagittal suture
  • internal occipital protuberance posteriorly
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21
Q
A

internal occipital protuberance

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22
Q
A

external occipital protuberance

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23
Q

outline the venous drainage of the brain

A
  • cerebral veins drain venous blood from the brain into dural venous sinuses
  • dural venous sinuses drain into internal jugular vein at jugular foramen
24
Q

which dural venous sinus drains into the IJV

A

sigmoid sinus

25
Q

where do the dural venous sinuses confluence

A

at the internal occipital protuberance

26
Q

why are facial veins atypical

A
  • they have thicker walls so wont collapse and have no valves
  • this means bacteria could travel up them to the ophthalmic veins and towards cavernous sinus
27
Q

cavernous sinus contents

A

CNIII, IV, V1, V2, VI and internal carotid artery

28
Q
A
29
Q
A

also, left CCA and subclavian artery

30
Q
A
31
Q

which artery supplies the lateral aspect of the cerebral hemisphere

A

left and right middle cerebral artery

32
Q

which artery supplies the medial aspect of the right and left cerebral hemisphere

A

R and L anterior cerebral artery

33
Q

where is the visual cortex located in the brain

A

posterior aspect

34
Q

which artery supplies the posterior aspect of R and L cerebral hemispheres (including visual cortex)

A

posterior cerebral artery

35
Q
A

?? are ophthalmic arteries

36
Q

where is the circle of Willis located in the skull

A

subarachnoid space

37
Q

outline CSF flow through ventricles of the brain

A

CSF formed in the choroid plexuses of each lateral ventricle flows into the 3rd ventricle, where more CSF is added by the choroid plexus here. It flows through the cerebral aqueduct of midbrain into the 4th ventricle, where another choroid plexus adds more CSF. The central canal of the spinal cord is continuous with the 4th ventricle.

CSF then enters the subarachnoid space through 3 openings in the roof of the 4th ventricle: (some CSF enters the central canal of teh spinal cord, whichb is continuous withb the 4th ventricle)

  • Single medial aperture (Magendie)
  • Paired lateral apertures (Luschka
38
Q

describe the reabsorption of CSF

A

CSF then returns to venous blood from subarachnoid space by entering dural venous sinuses through arachnoid granules into the superior sagittal sinus. The dural venous sinuses drain into the IJV at the jugular foramen.

39
Q

management of hydrocephalus

A
  • ventricular peritoneal shunt - sited within the peritoneal cavity
40
Q

where in the head is the middle meningeal artery located

A

between the bone and dura (remmeber can be damaged by pterion fracture)

41
Q

where in the ehad is the circle of willis located

A

subarachnoid space

42
Q

where in the mater layers are the cerebral veins located

A

they cross the subarachnoid space to drain into the dural venous sinuses

43
Q

what kind of aneursym causes a subarachnoid haemorrhage

A

circle of Willis eg berry aneurysm, these are often congenital

44
Q

what typically causes an extradural haemorrhage

A
  • between bone and dura
  • eg ruptured middle meningeal artery
  • can occur after trauma to the pterion
45
Q

what typically causes a subdural haemorrhage

A
  • between dura and arachnoid
  • eg torn cerebral veins
  • occurs after falls in the elderly and those with a drinking problem
46
Q

why is L3/4 the best space for a lumbar puncture

A
  • the cauda equina is here not the spinal cord (ends at L2) - these roots are less easily damaged than the conus medullaris
  • the vertebrae are not fused here (like the sacrum)
47
Q
A
48
Q

what goes through the anterior and posterior sacral foraminae

A

anterior and posterior rami of sacral spinal nerves

49
Q

supratentorial herniation: cingulate (subfalcine)

A

frontal lobe is pushed under the falx cerebri - most common type

50
Q

supratentorial herniation: central

A

squeezed through a notch in the tentorium cerebelli

51
Q

supratentorial herniation: uncal

A

brain the uncus (medial part) of the temporal lobe herniates inferior to the tentorium cerebelli

52
Q

supratentorial herniation: transcalvarial

A

brain squeezes through a fracture/gap in the skull

53
Q

infratentorial herniation

A

can be upward or downward (into the foramen magnum)

54
Q

which nerve can an uncal herniation damage

A

CNIII - ipsilateral fixed dilated pupil

55
Q

what do the vertebral arteries branch off

A

R and L subclavian arteries

56
Q

what can damage to the epidural venous plexus cause

A
  • epidural haematoma
  • can compress the spinal cord and cause cauda equina if large enough