lecture 4: meninges and ventricles Flashcards
how many meninges
3
what are the 3 meninges
dura mater
arachnoid mater
pia mater
which meninges is most superficial
dura
which meninges is the tough mother
dura mater
true or false: meninges are membranes
true
true or false: the outmost layer of meninges is pip mater
false, dura mater
describe dura matr
dense, fibrous
true or false, there is no vascularature in the dura mater
true
in the cranium, is there 1 or 2 layers of the dura mater
2
what are the two layers of the dura mater in the craniu
periosteal
meningeal
which dural layer is deeper: periosteum or meningeal
meningeal
true or false and explain: in both the cranium and the spinal cord, there are.2 layers of the dura mater
false, only 2 layers in the cranium
what is the middle meninge
arachnoid mater
which meninges has vasculature
arachnoid matter
describe the arachnoid mater
delicate, impermeable membrane on inner surface of dura matter
what do the trabecular in the arachnoid matter form
the subarachnoid space
what is the subarachnoid space filled with
cerebrospinal fluid (and vasculature
which layer is considered tender mother
pia mater
describe the pip mater
single layer of cells covering the surface of the brain and spinal cord (stuck onto the brain)
true or false: pia mater follows the sulci and gyri of the brain
true
what are the REAL spaces in the cranial meninges
subarachnoid space (between arachnoid matter and pip mater)
where is the subarachnoid space
between arachnoid mater and pip mater)
true or false: in cranial meninges, the epidural is considered a real space
false, a potential space
what are the POTENTIAL spaces in the cranial meninges
epidural space (between periostea dura mater and skull)
subdural space (between meningeal dura mater and arachnoid mater)
where is the epidural space located
(between periostea dura mater and skull)
where is the subdural space located
between meningeal dura mater and arachnoid mater)
why are epidural and subdural spaces considered potential spaces
because under normal circumstances there should not be space (only if there is a problem is there space)
where is the dural venous sinus located
between 2 dural layers
what are arachnoid granulations
projections of arachnoid mater that pierce the meningeal dura mater and project into dural sinuses
=channels enclosed between periostea and miningeal layers of dura
what is the function of the arachnoid
allows css to go into venous drainage
what are the REAL spaces in the spinal meninges
epidural space (between dura mater and bone)
subarachnoid space (between arachnoid and pia mater)
what is a potential space in cranial meninges but a real space in spinal meninges
epidural space
what is the epidural space filled with in then spinal meninges
with adipose tissue and internal vertebral plexus
true or false: in both the cranial and spinal meninges, the subarachnoid space contains CSf and vasculature
true
what is the potential space in the spinal meninges
subdural space (between dura mater and arachnoid)
why is there no periosteal layer in spinal dura mater
since the dura matter is not adhered to the bone
what does the meninge in the spinal nerve blend with
epineurium
what are the lateral extensions of the pia mater between spinal nerves
denticulate ligaments
what is the caudal projection of the pia mater
filum terminal
true or false, the filum terminal is covered in dura mater
true
what is the function of denticulate ligaments and filum terminal
anchor the spinal cord within the spinal column
what are the 4 dural reflections
falx cerebri
fax cerebelli
tentorium cerebelli
diaphragm sell
what two dural reflections are in the mid sagital plane
falx cerebri
falx cerebelli
what is a dural reflection
meningeal layer separates from periostea layer, folds on itself to fill space and then comes back
where is the falx cerebri located
between cerebral hemispheres
where does the falx cerebri attach
at the crest galli and extends to internal occipital protuberance
where is the falx cerebelli located
between cerebellar hemispheres
true or false: the falx cerebi is located between cerebellar hemispheres
false, located between cerebral hemispheres
what plane does the tentorium cerebelli lie in
transverse
where is the tentorium cerebelli located
between cerebrum and cerebellum
which dural reflection is located bw cerebral hemis
falx cerebri
which dural reflection is located between cerebellar hemis
falx cerebelli
which dural reflection is located between cerebrum and cerebellum
tentorium cerebelli
what is the diaphragma sellae
circular sheet suspended bw clinoid processes covering pitit (lid for sella turcica)
do venous sinuses have valves
no
movement can be directional (blood can back flow which can be bad for infections)
what are the venous sinuses
superior sagittal
inferior sagital
straight sinus
occipital sinus
cavernous sinus
sup and inf petrosal sinus
confluence of sinus
transvers and sigmoid sinus
where is the superior saggital sinus attached
outer border of falx cerebri
where is the inferior sagittal sinus attached
inner (free border) border of falx cerebri
what sinus is located at the junction of the falx cerebri and tentorium cerebelli
straight sinus
what sinus is located at the outer border of the falx cerebri
superior sagittal
what sinus is located at the free border of the flax cerebri
inferior saggiata
what sinus is located ay the outer (attached) border of falx cerebelli
occipital sinus
where is the occipital sinus located
outer (attached) border of flax cerebelli
WHERE do the transverse and sigmoid sinus drain
internal jugular vein
where do transverse and sigmoid sinus go
form deep grooves on interior surfaces of occipital, parietal and temporal bones
what is the cavernous sinus
venous plexus on either side of the sella turcica
which sinus is located on either side of the sella turcica
cavernous sinus
where do the superior pretosal sinus drain
drain into sigmoid s
where does inferior petrosal sinus drain
internal jugar vein
be able to locate venous sinuses and where they all drain
/
why is cavernous sinus important
numerous neurovasvulare structures located within
what are the structures that pass thru cavernous sinus
occulomotor
trochlear
ophthalmic
maxillary
abducents
optic chiasm
internal carotid artey
with an epidural hematoma, is the bleed venous or arterial in original
arterial
what is epidural hematoma caused by
damage to branches of the middle meningeal artery (embedded on outside dural mater)
what is the primary blood supply to the dura
branches of middle meningeal artery
explain epidural hematoma
often caused by head injury
pooling blood separates periostea dura from inside of skull
are subdural hematomas arterial or venous in origin
venous
what is another name for subdural hematoma
dural border hematoma
subdural hematoma is caused by damage to what structures
damage to bridging veins that drain into dural sinuses
explain subdural hematoma
pooling blood separates arachnoid mater from meningeal dura (subdural space)
pooling blood separates arachnoid mater from meningeal dura
which hematoma
subdural
pooling blood separates periostea dura from inside of skull
which hematoma
epidural hematoma
damage to middle meningeal a is associated with what hematoma
epidural
damage to bridging veins is associated with what hematoma
subdural
a subarachnoid bleed is arterial or venous in original
arterial
subarachnoid hematoma is caused by damage to what
cranial vasculature or rupture of saccular aneurysm
cranial vasculature or rupture of saccular aneurysm is associated with what hematoma
subarachnoid
where does blood collect in subarachnoid hematoma
blood and css collects along with CSF in existing subarachnoid space
true or false: epidural hematomas do not typically cross suture lines
true
why is it that epidural hematomas do not typically cross suture lines
since dura mater is tightly adhered
what shape do epidural hematomas form and why
biconvex (lemon) shape because since dura mater is tightly adhered so does not cross suture lines
true or false: subdural hematomas are restricted by suture lines
false
what shape are subdural hematomas and why
crescent (banana) because subdural hematomas are not restricted by skull sutures
what can increased intracranial pressure cause
herniation of cerebral/cerebellar tissue
space occupaying lesions (tumours, extra cranial bleeds)
what is a subfalcine hernia
cerebral tissue herniates to contralateral side under flax cerebri
cerebral tissue herniates to contralateral side under flax cerebri is associated to what hernia
subfalcinec
in subfalcine hernia, where does cerebral tissue herniates to
contralateral side under flax cerebri
what is a central or uncle hernia
deep cerebral tissue (central) or portion of temporal lobe (uncal) herniate through tentorial notch
deep cerebral tissue () or portion of temporal lobe () herniate through tectorial notch is associated to what hernia
central or uncle
in central or uncal hernia, where does tissue herniate through
through tectorial notch
what is a tonsillar hernia
ventral portion of cerebellar tissue (cerebellar tonsil) herniates through foramen magnum
ventral portion of cerebellar tissue () herniates through foramen magnum is associated with what hernia
tonsillar hernia
in tonsillar hernia, where does tissue herniate through
foramen magnum
why are many headaches believed to be dural in origin
due to sensitivity of dura mater to stretching and pain
=distension of meningeal vessels
=distension of scalp
=reduction in CSF volume
supratentorial dura mater is innervated by what
afferent meningeal branches of the trigeminal nerve
CSF is continuous produced from blood plasma by which cells
ependymal cells covering choroid plexus in all ventricles
ependymal cells are joined by tight junctions which create what
blood cerebrospinal fluid barrier
what is function of blood cerebrospinal fluid barrier
prevents anything other than CSF from coming in ventricles
what are the 3 main several functions of CSF
protection and support
maintenance of homeostasis
transport of nutrients
explain how CSF acts as protection and support
Wchanical shock absorption
Immune protection
Lessends weight of the brain
What are some ways that the csf maintains homeostasis
Removes waste
Maintains osmotic pressure
Temperature control
Why are arachnoid granulation’s important
We produce a lot of CSF so we need arachnoid granulation’s to reabsrop and prevent build up
Why do we have ventricles (embryoligic)
CNS developed as a hollow tube
Ventricles are derivatives of the lumen
What is the location of csf production
Ventricles
True or false: ventricles are normally filled with blood
False, with csf
What’s are the ventricles
Lateral (2)
Third ventricle
4th ventricle
What is the name of the ventricle that are in each cerebral hemisphere
Lateral
The lateral ventricles are part of which part of the brain
Telencephalon
The lateral ventricles cover what lobes
Frontal
Parietal
Occipital
Temporal
The 3rd ventricle is in what part of the brain
Diencephalon
What ventricle is the midline structure between each diencephakon on each side
3rd
Where is the 4th ventricle located
Between cerebellum and brain stem
Which ventricle is located between cerebellum and brainstorm
4th ventricle
What structures connect the lateral to third ventricles
Interventricular foramina
True of false: the intraventicular foramina connect the 3 and 4 ventricle,
False connects the lateral to third
The cerebral aqueduct is located in what part of the brain
Messncephalon
What structure connects the 3 to 4 ventricles
Cerebral aqueduct
True or false: the cerebral aqueduct connects the 3 to 4 ventricle s
True
Where is the central canal locat3
Spinal cord
How many lateral apertatures do we have
2
What structure connects the 4 ventricle to the subsarachnoid space
Median and lateral aperatures
What is the function of the median and lateral aperaturs
Connect the 4 ventricle to the subarachnoid space
what are the 4 parts of the lateral ventricles
Anterior horn
Inferior horn
Posterior horn
Body
The inferior horn of the lateral ventricles is located in what lobe
Temporal
The anterior horns of lateral ventricles are divided by a thin membrane called the blank
Septum pellucidum
True of false, the septum pellucidum separates the 3rd ventricle from the 4th
False, separates the 2 anterior horns of the lateral
What are the walls of the 3rd ventricle formed by
By diencephalon on each side
What does the shape of the 3rd ventricle follow
Follows the space created between the two thalami and hypothalamic
The hole is the third ventricle allows what
Allows massa intermedia to connect thalami
The 4th ventricle is continuous with what
Central canal and subarachnoid space
The 3 aperatures of the 4th ventricles drain csf to where
Into subarachnoid space surrounding brain brain stem and spinal cord
True or false: the cerebral aqueduct is in the mid brain
True
Continuous production of cerebrospinal fluid necessitates what
continuous reabsorption / drainage
True or false: flow of csf is unidirectional
False
What are the two main pathways of csf fluid drainage
1) Drainage into dural venous sinuses, facilitated by arachnoid
granulations (primarily in superior sagittal sinus, but located
throughout cranial & spinal meninges)
2. Drainage along sheaths of cranial and spinal nerves to
surrounding lymphatic vessels (e.g., along olfactory nerves through foramina of cribriform plate)
Drainage of csf into Dural venous sinuses is facilitated by what
Arachnoid granulations
Where are arachnoid granulation’s located
Superior sagital sinus (main)
But also throughput cranial and spinal meninges
True or false : hydro cephalon can be congenital or acquired
True
What is Latin translation of hydrocephalus
Water head
What is hydrocephalus associated with
abnormal Accumulation of csf
What are the two categories of hydrocephalus
• Non-communicating: CSF flow is blocked (e.g., in one of the narrow connections between ventricles)
• Communicating: CSF flow remains unrestricted in
ventricles and into subarachnoid spaceà overproduction or failure to drain
Explain non communicating hydrocephalus
• Non-communicating: CSF flow is blocked (e.g., in one of the narrow connections between ventricles)
Explain communicating hydrocephalus
• Communicating: CSF flow remains unrestricted in
ventricles and into subarachnoid spaceà overproduction or failure to drain
What is treatment of hydrocephalus
Treatment may involve a catheter used to drain CSF into another body cavity (e.g., ventriculo-peritoneal shunt)
