Meninges, Ventricles, CSF Flashcards
_______ are a specialization of the sub-arachnoid space that allow for circulation of the CSF.
arachnoid villi (arachnoid granulations)
CSF circulates in the ______ space.
subarachnoid
Severed middle meningeal artery leads to ___________.
epidural hematoma (potential space between scull and dura)
Epidural hematoma is shaped like a _______ and the onset is ________.
lens shaped
rapid onset
Arachnoid trabeculae attach to __________.
pia mater
Arteries run in the _______ space.
subarachnoid space
Bleeding between dura and arachnoid is called?
subdural hematoma
Subdural hematoma occurs when ________ tears.
cerebral VEINS
lower pressure bleed than arterial
Sickle cell shaped bleed is associated with ______ hematoma.
subdural hematoma
Bleed of cerebral arteries causes ________ hemorrhage.
subarachnoid
Which type of hemorrhage is most common?
subarachnoid
With subarachnoid hemorrhage, the blood fills _______.
sulci
Hunt&Hess (neuro exam) and Fisher Scale (CT) are severity indicators for which type of hemorrhage?
subarachnoid
The middle of the brain begins to shift under the flax when what occurs?
Mid-line shift: a brain accommodation that occurs with slowly developing hemorrhages
HIgh pressure bleeds are associated with
rapid onset arterial bleeds (epidural and subarachnoid hematomas)
Infection of the meninges due to virus or bacteria usually affects which layers?
pia
arachnoid
Meningitis signs:
fever, nuchal rigidity, headache, stupor, coma
Mortality rate for meningitis?
10-20%
Highest incidence for meningitis?
<15 YOA (related to immune system)
What can meningitis cause?
venothrombosis
hydrocephalus
What are the 5 parts of the lateral ventricle?
Frontal horn, body, posterior/occipital horn, inferior/temporal horn
What lobes does the lateral ventricle run through? What shape is it?
all the lobes! C-shaped
Where the body, posterior/occipital, and inferior/temporal horns meet is called the
trigone or atrium
Which ventricle is in the midline of the diencephalon?
third ventricle
Opening of the 3rd ventricle that connects with lateral ventricles is called?
interventricular foramen of monroe
Describe the circulation of CFS starting from the lateral ventricle
lateral ventricle interventricular foramen 3rd ventricle cerebral aqueduct 4th ventricle lateral/median apertures subarachnoid space arachnoid villi superior sagittal sinus
The “roof” of the 4th ventricle is made of?
superior medullary velum and inferior medullary velum (roof is peaked)
The “floor” of the 4th ventricle is _______ shaped, called the _______.
diamond-shaped
rhomboid fossa
The median aperture is a funnel-shaped hole in the inferior medullary velum that communicates with the
subarachnoid space
There are 2 lateral apertures that are also known as? Located where?
foramina of Luschka
at the ends of each lateral recess
4th ventricle ends in ______ which continues into the SC.
central canal
The 4th ventricle is between which structures?
cerebellum and pons/medulla
What cells absorb plasma then transform it to CSF and secrete it?
choroid cells
What qualities of the choroid plexus make it effective?
highly convoluted (increased SA)
fenestrated (leaky) capillaries
choroid epithelium lines the ventricles
Where is the choroid plexus located?
parts of lateral ventricles
roof of the 3rd ventricle
lower 4th ventricle to median aperture
Compare and contract plasma and CSF
colorless liquid, low in cells and PRO
CSF has > Mg and Cl than plasma
CSF has < K and Ca than plasma
Total volume of CSF turns over how many times/day? How much produced?
4 times per day
600-700mL per day
What is the primary fxn of CSF?
support and cushion the brain
Total volume of CSF in adult?
Volume of ventricles?
140mL
25mL
What are the 3 possible mechanisms for hydrocephalus?
- increased production
- blocked circulation (most common area is cerebral aqueduct)
- deficiency of resorption
Rare tumors of the choroid plexus are called _______. What do they cause?
papillomas
cause increased production of CSF
Tumors, congenital failure of lateral/median apertures to open, adhesions of meninges, and trauma can all cause
blockages of CSF circulation
Deficiencies of resorptions are caused by
?congenital absence of arachnoid villi or increased pressure in superior sagittal sinus
What structure acts as a barrier between CSF and venous blood?
arachnoid villi
non-communicating hydrocephalus is due to
blockage in the ventricles (CSF cannot get to the subarachnoid space)
communicating hydrocephalus is due to
CSF reaching subarachnoid space and getting blocked outside of the ventricles
Shunts are places to
decrease pressure
quasi-permanent shunts empty into
internal jugular vein or peritoneal cavity
for chronic conditions
temporary shunts empty into
external ventricular drain (bag)
for trauma/brain bleeds
What is the primary fxn of meninges?
stabilize and protect the brain and SC
- literally suspends brain from scull
- cushions brain with CSF
Most superficial layer of dura mater is called the
periosteal layer
Deeper layer of the dura mater is called the
meningeal layer
What dural reflection occupies the longitudinal fissure and separates the 2 hemispheres?
falx cerebri
What dural reflection separates the cerebellum from occipital bones?
tentorium cerebelli
supratentorial and infratentorial compartments
falx cerebri attaches anteriorly to ______ and posteriorly to ________.
ant: crista galli
post: tentorium cerebelli
Tentorial notch: the space int he tentortium through which the _____ passes.
brainstem
Tentorium cerebelli attaches post to_______ and contineus to the _________ of the temporal bone.
post: occipital bone
cont. to the petrous portion of temporal bone
Brain tissue under pressure may herniate under/around which tissues?
falx cerebri and tentorium cerebelli (firm edges!)
The separation of the 2 layers of dura form specific sinuses that act as _________.
venous channels: contain venous blood, no valves, cerebral veins empty into them
Which sinus has CN III, IV, VI, V and internal carotid artery running through it?
cavernous sinus
Which sinus empties into internal jugular vein?
sigmoid sinus
What are the meningeal layers from superficial to deep?
- epidural space
- periosteal dura
- meningeal dura
- subdural space
- arachnoid
- subarachnoid space
- pia
