Meninges, Ventricles, and CSF Flashcards
(33 cards)
What comprises the leptomeninges?
- Arachnoid mater
- Pia mater
What are the two layers of the dura mater? Which layer contains the meningeal arteries?
- Outer periosteal layer
- Inner meningeal layer
- Outer periosteal layer contains the meningeal arteries
Is there normally a space between dura and cranium?
No… the cranial epidural space is considered a potential space. It becomes fluid-filled only in pathological conditions.
Which veins have an important route for the spread of infection?
emissary veins
Do diploic veins exit the cranium?
No! This is why emissary veins are the vessels that serve an important role in the spread of infection.
Which space is filled with CSF?
subarachnoid space (b/t arachnoid and pia)
Which structures are responsible for draining CSF into dural venous sinuses?
arachnoid granulations or villi
Arachnoid villi act as_______for the flow of CSF into venous blood.
one-way valves
What is the main stimulus that causes arachnoid villi to open?
hydrostatic pressure (CSF pressure is normally greater than central venous pressure)
Spinal epidural space is filled with what?
connective tissue and vertebral venous plexus
What does the lumbar cistern contain?
CSF and nerve roots of cauda equina
What causes an epidural hematoma vs. subarachnoid hemorrhage vs. subdural hematoma?
- Epidural hematoma: skull fracture at/near pterion that tears a meningeal artery
- SAH: ruptured cerebral aneurysm that occurs spontaneously or as a result of a head injury
- SDH: traumatic brain injury (esp. deceleration injuries) that tears bridging veins crossing the subdural space
Where is the most common place for a cerebral anuerysm to occur?
bifurcation of anterior communicating artery and anterior cerebral artery
Which is the most lethal of all head injuries?
acute subdural hematomas due to trauma (must be rapidly treated with surgical decompression)
What is CSF secreted by?
choroid plexuses
What is the total volume of CSF? How much is in the ventricles at any given time?
- Total volume=90-150 mL
- 23 mL is in the ventricles; rest is in the subarachnoid space
Large pickets of subarachnoid space, corresponding to major irregularities in the surface of the CNS:
subarachnoid cisterns
Which is the most prominent intracranial cistern?
cisterna magna (b/t medulla and inferior surface of cerebellum)
What are some of the strongly buffered substances in the brain?
glucose, calcium, potassium, and proteins (all are present in CSF in decr. conc. compared to blood serum)
Which ions are present in increased concentrations in the CSF compared to blood serum?
sodium, chloride, and magnesium
Where are the lateral ventricles located?
telencephalon
Where is the third ventricle located?
cavity of diencephalon
Where is the fourth ventricle located?
cavity of rhombencephalon
Where do the lateral ventricles drain?
into the 3rd ventricle via the interventricular foramina of Monro
