Meninges and CSF

Question 1

what do the meninges cover?

Answer 1

brain and spinal cord

Question 2

what are the four layers of the meninges?

Answer 2

1. dura mater
2. arachnoid mater
3. subarachnoid space
4. pia mater

Question 3

describe the dura mater

Answer 3

tough, thick covering

splits into periosteal and meningeal layer that enclose the dural venous sinuses

Question 4

what is the sensory supply of the dura mater?

Answer 4

CNV (headaches)

Question 5

what does the subarachnoid space hold?

Answer 5

CSF and blood vessels

Question 6

what does the arachnoid mater have?

Answer 6

arachnoid granulations

Question 7

what does the pia mater do?

Answer 7

adheres to brain

Question 8

where can the subarachnoid space be accessed

Answer 8

lumbar puncture at L3/4 or L4/5 to obtain a CSF sample

Question 9

what level does the spinal cord end?

Answer 9

L2

Question 10

what level does the subarachnoid space end?

Answer 10

S2

Question 11

what secretes CSF?

Answer 11

choroid plexus (epithelial pia in lateral and third ventricles)

Question 12

how does CSF flow from the 3rd to the 4th ventricle?

Answer 12

cerebral aqueduct

Question 13

where does the CSF drain after the 4th ventricle?

Answer 13

subarachnoid space and some into the central canal to the spinal cord

Question 14

what reabsorbs CSF?

Answer 14

arachnoid granulations and passes into dural venous sinuses

Question 15

define raised intracranial pressure

Answer 15

this is increased pressure in the cranial cavity (enclosed space so cannot stretch)

Question 16

what does the constant intracranial volume consist of?

Answer 16

brain
blood
CSF
other components such as nerves, blood vessels

Question 17

define Monro-Kellie hypothesis

Answer 17

balance of cranial contents

Question 18

what can differences in contents of the cranial cavity cause?

Answer 18

damage
herniation
constriction of tissues
pushed out through gaps in the cranial cavity e.g. superior orbital fissure

Question 19

what symptom do most people with raised ICP report?

Answer 19

vision change

Question 20

what covers the optic nerves?

Answer 20

meninges

Question 21

how does raised ICP affect the optic nerves?

Answer 21

it is transmitted along the subarachnoid space in the optic nerve sheath and can compress the optic nerve and central artery and vein of the retina

Question 22

what affect does raised ICP on the optic nerve appearance have?

Answer 22

swollen/bulging optic discs (papilloedema)