Meninges + CSF

Question 1

Describe the meningeal layers

Answer 1

dura mater - outer fibrous layer, blends with periosteum
arachnoid mater - inner thin delicate later
pia mater - microscopic, in direct contact with brain

Question 2

Functions of the meninges

Answer 2

protect and enclose the brain, spinal cord + CSF

supporting framework for arteries, veins and venous sinuses

Question 3

Name and describe the meningeal spaces

Answer 3

extra dural space = potential space between dura mater and periosteum

subdural space = space between dura and arachnoid mater

subarachnoid space = space between arachnoid and pia mater

no space between pia mater and brain as pia mater lines the surface of the brain

Question 4

How is the dura mater different in the vertebral column?

Answer 4

dura mater is not adherent to the periosteum - true space = epidural space

Question 5

What is the different between epidural and extradural spaces?

Answer 5

epidural = true space in vertebral column between dura mater and periosteum

extradural = potential space around brain between dura mater and periosteum

Question 6

What is the arterial supply to the cranium and dura mater?

Answer 6

middle meningeal artery
branch of maxillary artery
branch of external carotid artery
passes through foramen spinosum

Question 7

What bones articulate at the Pterion?

Answer 7

frontal
parietal
sphenoid
temporal

Question 8

What can trauma to the side of the head cause?

Answer 8

damage to the middle meningeal artery
causing bleed between periosteum and dura

increase in pressure strips dura away from periosteum
extradural haemorrhage

Question 9

What does rupture of a brain aneurysm cause?

Answer 9

subarachnoid haemorrhage
highlights gyri

Question 10

What is the difference between a subarachnoid haemorrhage and an intracerebral haemorrhage?

Answer 10

intracerebral haemorrhage is more focal, involves smaller branches within substance of brain or ventricles

Question 11

What can increase the risk of an intracerebral haemorrhage?

Answer 11

hypertension
diabetes mellitus
alcoholism

Question 12

Describe the venous drainage of the brain

Answer 12

cerebral veins drain into venous sinuses within the dura mater
cerebral veins cross subarachnoid space

Question 13

What can trauma to the front/back of the head cause?

Answer 13

shearing force on veins
weaker in elderly/malnourished/alcoholics
bleed between arachnoid and dura mater
subdural haemorrhage - venous bleed
crescent moon shaped bleed

Question 14

Where are the ventricles found in the brain?

Answer 14

lateral ventricles in cerebral hemispheres
3rd between 2 halves of diencephalon
4th posterior to pons and medulla

Question 15

What does the choroid plexus do?

Answer 15

produces and secretes CSF in response to hormone, CSF pressure and blood pressure stimuli

Question 16

Where is CSF produced?

Answer 16

choroid plexus

Question 17

How and where is CSF reabsorbed?

Answer 17

reabsorbed by arachnoid granulations
drained into venous system
controlled by hormones, blood and CSF pressure

Question 18

CSF functions

Answer 18

glucose-rich plasma-like solution
provides buoyancy to brain
acts as a shock absorber
homeostasis
waste disposal system

Question 19

What is hydrocephalus?

Answer 19

excessive CSF present due to over-production or lack of drainage

can be caused by:
- congenital narrowing of foramina or duct
- infection/inflammation causing narrowing of foramina or duct

build up of fluid dilates lateral ventricles

Question 20

What can cause leakage of CSF and where does it normally leak?

Answer 20

commonly due to trauma (fracture of cranial fossa)

CSF leaks through ethmoid bone into nasal cavity

persistently runny nose - positive glucose test

increased risk of meningitis