Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
166 Cards in this Set
- Front
- Back
|
he we go!
|
|
|
What are the two types of space occupying lesions? (SOLs)
Define them |
Intraranial- inside of the skull
Extracranial- outside of the skull (scalp) |
|
|
What are the two types of intracranial SOLs?
Do the terms make sense? |
Extraxial- outside the brain parenchyma
Intraxial- inside the brain parenchyma no they make no sense |
|
|
Give an example of an extraaxial SOL.
|
subarachnoid hemorrhage or meningioma
|
|
|
What is an aponeurosis?
|
a flat tendon
|
|
|
HAT APONEUROSIS IS ON TOP OF THE SKULL? wHAT MUSCCLES does it connect?
show |
the EPICRANIAL/GALEAL aponeurosis connecting the the two bellies of the occipitofrontalis muscle
|
|
|
What nerve controls the occipitofrontalis muscle?
How do you deduce this? |
CN 7 because this muscle is involved in facial expression
|
|
|
Show the layers of the scalp
|
|
|
|
Is it easy to scalp someone? Why?
|
yes because under the galeal aponeurosis is loose areolar tissue that slides right off.
|
|
|
What is another name for the periosteal dura mater?
|
the endocranium
|
|
|
What is the epicranium then?
|
the layer of CT right on top of the skull on the other side
|
|
|
Which layer is fused more tightly to the skull? (clinically important)
|
the outside epicranium
|
|
|
How much of our energy does the brain take up?
What is the thermal consequence of this for the head? |
30%, which means it makes a ton of heat
|
|
|
How does out body deal with all this heat?
|
with a VERY rich blood supply draining the head
|
|
|
So what happens if we lacerate the scalp?
|
profuse bleeding
|
|
|
Does this mean we will bleed out? Why?
|
no because the scalp vessels tend to mend themselves quite quickly
|
|
|
Why don't we usually have infections of the scalp?
|
because the blood supply is so rich and those cells are very well taken care of
|
|
|
What arteries give the vascular supply to the scalp?
Are they independent? |
the external and branches of the internal carotid arteries.
External comes from the ear Internal comes from the orbit out from the brain They anastomose just like the cerebral arteries! |
|
|
How is the pediatric skull different that the adult skull in terms of composition?
|
pediatric- more marrow
adult- more linear trabeculae |
|
|
If you hit someone over the head with a hammer, what pattern of skull fx would they get if they were an adult vs a kid?
Why? |
adult- linear, EGGSHELL fractures
because of the hard trabeculae that crack like an egg does child- blood filled depressions called POND fractures (PIC ABOVE) because they have soft marrow that fills the fx with blood |
|
|
What is a diastasis?
|
a sepration of structures that are normally joined together
|
|
|
When can you get a diastasis of the skull?
|
rupture along the suture line
|
|
wHAT KIND OF FX IS THIS?
|
linear/eggshell
|
|
|
|
|
|
Why are slightly larger babies always having to go through C sections?
|
because we are at the sweet spot in evolution where the infant head is JUST large enough to fit through the pelvis
|
|
|
What has the fetal skull develped to get over this?
|
fontanelles, which are membranes between the unfused skull bones
|
|
|
How many pieces is the frontal bone in at birth? hOW IS IT SPLIT?
|
2 pieces split down the saggital
|
|
|
Why do you have to be aware of this fact?
Show pic. |
METOPIC SUTURE
usually this closes pretty well and leaves no sign, but it persists partially or totally in some people. It is totally benign and you shouldn't mistake it for a fracture. |
|
|
|
|
|
|
|
|
When does the last fontanelle close and which one is it?
|
the anterior that closes at 18 months
|
|
|
What does the anterior fontanelle fuse to become?
|
the bregma marking the intersection of the saggital and coronal sutures
|
|
|
What does the posterior fontanelle become?
|
the lamda
|
|
|
What do the sphenoid and mastoid fontanelles become?
|
bone protuberences of the skull
sphenoid- pterion mastoid- asterion |
|
|
What does pterion mean and why is it named that?
|
wing-like because it is lateral to the lesser wing of the sphenoid
|
|
|
What does asterion mean and why is it named that?
|
star-like because that's what it looks like
|
|
|
Can you separate the meningreal and periosteal dura?
|
not in the brain
|
|
|
What are the dura septa good for protecting against?
|
rotational and translational motion of the head from us josling around.
This is good for our bipedal lifestyle. |
|
These are the two dural septa
|
falx cerebri and tentorium cerebri
|
|
|
What separates the vermis of the cerebellum?
|
|
|
|
What does the falx cerebri attach to?
|
|
|
|
What does galli mean? Why is it called this?
|
chicken because this looks like the crest of a chicken
|
|
|
What bone is the crista galli on?
|
the ethmoid
|
|
|
What is the supra vs infra tentorium dura innervated by?
|
supra- trigeminal nerve
infra- spinal nerves |
|
|
What branch of CN 5 innervates most of the supratentorial dura and what referred pain does this give?
|
the opthalmic so forehead pain
|
|
|
Specifically what nerves innervate the infratentorial dura?
|
C2 and meningeal branch of the vagus
|
|
|
So what can mimic a infratentorial stroke in terms of pain distribution to posterior neck and occiput?
|
an entrapment of CN 2 from spinal stenosis and head turning
|
|
|
What happens to cerebral vessels with increased ICP?
|
they collapse
|
|
|
What builds up in the cerebral blood when they collapse?
|
CO2
|
|
|
What does the brain do inresponse to increased CO2?
|
tell the rest of the body to increase blood flow by increasing systemic BP
|
|
|
What reflex does the increased BP trigger?
|
bradycardia
|
|
|
What else get stimulated in the brain?
|
irregular breathing
|
|
|
So what is Cushings triad of sx and what does that indicate?
|
1. hypertension
2. bradycardia 3. irregular breathing indicates raised ICP |
|
|
What are the meningeal arteries trying to supply?
|
the skull itself
|
|
|
What layer do the meningeal arteries start in and where do they end up?
|
in the epidural layer, but they manage to squeeze through the periosteum to lie against the skull
(they have their own impressions) |
|
|
where do the major branches of the meningeal arteries start off?
|
one in the pterion, the other below it
|
|
|
What groove is on the other side of the asterion?
|
the transverse dural sinus
|
|
|
How do all the different arteries (above and below) the skull drain?
What layer is this is? |
to the dural neveouns sinus in the epidural space
|
|
|
What are these veins that drain dural sinus blood to the outside of the skull called? Do they halve valves?
|
Emissary veins
No they don't |
|
|
Define emissary
|
person sent on a mission
|
|
|
What is the biggest risk via these emissary veins?
|
backflow into the head brigning a scalp infection to the brain
|
|
Is this the only cererbral dural sinus
|
no there is an inferior saggital sinus
|
|
|
Did najeeb tell the whole story of dural venous drainage?
|
No, there is a big straight sinus in front of the transverse sinuses that drain the great cerebral vein of galen and the inferior saggital sinus
|
|
|
What sinus does the pituitary sit in?
|
the cavernous sinus
|
|
|
What is the pituitary completely surrounded by here?
|
veins of the sinus
|
|
|
Which cranial nerves pass through the cavernous sinus? (hint they are all headed to one place)
|
everything headed to the orbit (all 3 occular CN and the two trigeminal)
|
|
|
What other vessel passes throught the cavernous sinus besides the sinus veins?
|
the two branches of the internal carotid (good for cooling the blood down)
|
|
|
What motor and sensory sx can you get from cavernous sinus compression then?
|
1. opthalmoplegia (esp of abducens nerve first)
2. paresthesias to frontal and maxillary face |
|
|
How does the cavernous sinus drain?
|
Into 2 petrosal sinuses (o top of petrosal bone)
the inferior meets the internal jugular at the sigmoid sinus |
|
|
What does petrossal mean?
|
hard
|
|
|
How do you know what order the CN's pass through the cavernous sinus?
|
the order they exit out the midbrain
they travel in the dura and head up to the superior orbital fissue |
|
|
|
|
Observe and decipher this.
Which side gets more blood? When does this happen? Which sie drains the vein of galen and inferior cerebral? |
right gets more blood at the end of superior sag sinus
but left lets all the inferior sag and great vein drainage! |
|
|
What is the pressure in the brain veins compared to the heart?
|
-10mmHg
|
|
|
What implication does this have for drainage?
|
blood is being sucked into these veins
|
|
|
Why shouldn't you pop pimples around your nose?
|
this frontal/maxillary region can drain into the cavernous sinus and cause a brain infection
|
|
|
What 3 types of infections can an emissary vein bring in from the scalp?
|
skull- osteolyelitis
meninges- meningitis brain- encephalitis |
|
|
What are two emissary veins of the cavernous sinus?
|
inferior and superior opthalmic veins
|
|
|
What veins do these veins form connections with on the face?
show the overlap area. What is this called? |
the facial vein and the pterygoid venous plexus
danger triangle |
|
|
So what types of disturbances can work their way back to the sinus?
|
infections of themiddle face or pharynx
|
|
|
What would these infections of the dangerzone cause?
|
cavernous sinus thrombosis or thrombophlebitis
|
|
|
why does thrombosis tend to occur hear?
|
blood is slow flowing and favorable for growth
|
|
|
What are the sx of a cavernous sinus infection?
|
paralysis of all the CN's through the superior orbital fissure
bulging and pulsation of eyes being pushed out |
|
|
What cst can this progres t if it gets past the vein layer?
|
meningitis
|
|
|
Is blood through all dural sinuses slow?
|
yes
|
|
|
WHy can you really not dissect the pia rom the brain?
|
it follows and covers the arteries into he brain to maintain the BBB
|
|
|
What are two additional names for communicating and noncommunicating hydrocephalus?
|
comm- external and extraventricular obstructuve
noncomm- internal and intraventricular obstructive |
|
|
Are Ct's taken as a perfectly axial cut?
|
no, it is taken according to the orbital meatal line so the posterior side has a more inferior cut
|
|
What is this? What is the sign called and what side is it on? Why?
|
Cord's sign of a hyperdense thrombosis of right transverse sinus showing clotted blood.
more blood drains on right so it's more likely to have it here |
|
|
Who had a right transverse thrombus? Why?
(hint- most common cause of dural venous thrombosis) |
Hilary clinton who got one when she fell (trauma)
also high coagulants can predispose you to this |
|
What is this? What causes it?
|
Beaten silver sign for a child.
It's when a noncommunicating hydrocephalus is so bad that the gyri wear into the skull and create these bumpy lines on it. |
|
|
What color is CSF in T1W vs T2W?
|
T1W- grey
T2W- white |
|
What does this indicate?
|
meningitis causing raised ICP
|
|
|
Why do people retract their legs in a positive kernig's and brudzinski's?
|
to shorten the sciatic nerve that reaches all the way down the leg from the spinal cord
|
|
|
What are 2 ways in which the fontanelles are advantageous for treating and monitoring a baby?
|
test- can easily insert things in there to monitor or take blood
monitoring- bulding means increased ICP, depressed means dehydrated |
|
|
How should the fontaelle look normally?
|
slightly depressed
|
|
|
In raised ICP, what starts to happen to the psition of the brain?
|
it gets pushed down toward the foramen magnum
|
|
|
What are the 2 cranial nerves that tend to get straetched most commonly in raised iCP?
What are their separate resons? |
CN3- uncus starts to roll over tentorium and pushes on CN 3
CN6- has to travel longest to get to SOF so it is already stretched IGNORE BOTTOM GREEN STRIPS |
|
Where is CN5 sitting?
|
|
|
Where is the petrosal ridge and the internal auditory meatus?
|
|
|
|
What can ou do to sample blood coming from only one side of the cavernous sinus?
|
insert something via the internal jugular and have it split into the inferior petrosal sinus at the internal auditory meatus
|
|
Where do 9, 10, and 11 exit vs 7 and 8?
name the foramen for each. |
7 and 8 - internal auditory meatus
9, 10, and 11- right behind it in the internal jugular foramen |
|
|
What is the part where all the dural sinuses meet called?
|
confluence of sinuses
|
|
Show where CN 12 is
wHAT BONE IS IT ON? |
the anterior rim of the foramen magnum
|
|
|
What is the only openings in the anterior cranial fossa?
|
the obfactory foramen by the cribiform plates
|
|
|
Where are the 3 cranial fossas? (supra vs infra tentorial)
|
supra- anterior and middle
infra- posterior |
|
|
Is the CN 3 or 4 thicker? Why?
|
CN 3 because it controls more things so needs more neurons.
|
|
What is the palsy here?
|
Left CN 3
|
|
What is the palsy here?
|
CN 6
|
|
|
What motion will pt's tend to have if there in a CN 4 lesion? Why
|
a head tilt to the opposite side to match their other eye up to the external rotation of the other eye
|
|
|
How do you test for a CN 4 lesion? What is the test called?
|
Bielschowski's head tilt test
|
|
|
What should you ask the pt to do and what do you expect to see with a CN 4 lesion?
|
tilt their head toward the side of suspected lesion.
Other eye will externally rotation without the affected side being able to internally rotate. This results in more severe double vision. |
|
|
With a CN 6 lesion, why can't the oblique muscles make up for it and adduct the eye?
|
because once you adduct, those muscles lose the ability to abduct because their force has gone over the axis (think about it)
|
|
What cn disturbance does kristen bell have?
|
left CN 6 lesion
|
|
How can you tell this is papilledema?
|
it looks like it is bulging out (look at shadow making a hillock)
|
|
What does this person with medial strabismus and papilledema likely have?
|
increased pressure in cavernous sinus
|
|
|
How can you compare coup counter coup to a bucket of water?
|
If you kick a bucket of water, it will spill over the other side because the water gets inertia
|
|
|
What creates the vaccuum and the actual injury in a coup counter coup?
|
a vaccuum created when the skull goes flying back and CSF has not yet caught up
the injury happens when the CSF and brain catch up to the skull that has stopped and smacks into it |
|
What happened here? Why is the injury in the cerebellum?
|
he hit his cerebellum against one of the dura infoldings, which are also quite hard
|
|
|
Now WE GET TO CLINICAL CORRELATIONS AND SOLs
|
yay!
|
|
|
What are 3 commonly calcified brain structures as people get older?
|
pineal gland, choroid plexuses, arachnoid granulations
|
|
|
How should the ventricles appear in a child vs adult?
|
chidren have slit like ventricles
|
|
|
How is blood removed from the brain in 2 stages after bleeding?
|
After it bleeds out, it becomes oxidized to methemoglobin over time
Then it will absorb water to become a hemorrhagic cyst |
|
|
How does a bleed appear on a CT in it's 3 stages of...
New Over TIme During resolution Why? |
New- hyperdense cause blood is
Over TIme- isodense cause methemoglobin is During resolution- hypodense because it has water |
|
|
How much additional pressure can the brain accomodate?
|
5-10 mmHg (not much)
|
|
|
Is the worst of the pressure threat to the brain over after the bleed stops?
|
no because it will absorb water over the day it resolves
|
|
exxtra axial SOLs: answer yellow
|
|
|
exxtra axial SOLs: answer pink
|
|
|
|
Under what layer will you start to see boundaries made by suture lines?
|
underneath the pericranium
|
|
take a look
|
ok
|
|
|
Which kind can reach the eyes?
|
anything above the pericranium (subgaleal or caput succedaneum)
|
|
|
Synonym for subgaleal bleed?
|
cephalohematocele
|
|
|
Is the brain the same consistency as in our anatomy lab?
What can you compare a live brain to texture wise? |
no
it is like tapioca pudding and will flatten out |
|
What kind of hemorrhage was this?
|
epidural
|
|
|
Why is the temple the most common place to cause an epidural hemorrhage?
|
the anterior middle cerebral artery passes under it and it is also one of the thinnest parts of the skull
|
|
|
Is the skull fx always where the lens shaped hematoma is? Why?
|
No because it leaks into whatever suture space the fx was in so the fx is not centered.
|
|
|
Show and tell what additional info you need to say where the fx is.
|
A CT bone window to see the skull separately
|
|
|
Is a subdural very sudden and acute? How do you know?
Why do bridging veins rupture here? |
no, elderly pepole can walk around for a long time with it cause it is slow
the two dura and the arachnoid/pia are very close to one another. The biggest leap for the bridging veins is in the subdural space |
|
|
What happens to all our nasal mucous? How does it drain?
|
it drains into our parynx
|
|
|
What position does our head need to be in to do this?
|
tilted slightly back
|
|
|
How much mucous do we swallow a day
|
1 quart
|
|
|
Where does blood tend to pool in a subdural hematoma then?
|
at the front of the head because the brain sinks to the bottom
|
|
|
What line can a subdural not cross? Why?
|
the midsaggital line falx cerebri blocks it here when the brain is pushed up against it
|
|
|
Which type of brain hemorrhage causes the most midline shift? Why?
show |
subdural because it has the greatest volume of blood on one side
the epidural is limited by sutures sub arachnoid is on both sides |
|
|
Does a fx necessarily need to happen to lead to an epidural?
|
no, it can jst be a step off of the skull bones from a diastasis
|
|
|
What kind of trauma force would cause a fx vs a diastasis?
|
fx- sharp, concentrated pressure like a hammer
diastasis- diffuse force like a rubber mallet |
|
What is this?
|
intraventricular hemorrhage
|
|
What is this sign called?
|
chalice sign
|
|
|
What is it from?
What bleed does it indicate? |
blood pooling in the area where the falx cerrebri hits the tentorium and clotting
a subarachnoid bleed |
|
|
What happens to the appearance of gyri and sulci in a SA bleed? Why?
|
they disappear because blood is filling in those spaces
|
|
|
What kind of hydrocephalus is a SA bleed considered as?
|
extraventricular obstructive hydrocephalus
Communicating |
|
dx this
|
bilateral subdural hematoma
|
|
|
Will there be any mass effect in an ischemic stroke?
|
Yes
|
|
|
Why?
|
as the tissue dies, it swells because it realses contents of cells (raised osmotic pressure) and also calls upon inflammation after necrosis
|
|
What happened in each spot?
|
red- new ischemic stroke
pink- old ischemic stroke |
|
|
Why does the new ischemic stroke look like it is just a piece of grey smudged on?
|
it kills both white and grey matter so the differentiation between them is lost
|
|
|
Why is the older ischemic stroke less dense then the new one?
|
tissue has been removed from it
|
|
|
Why is the newer ischemic stroke less dense then the brain parenchyma?
|
doesn't have any blood in it and much less metabolic activity
|
|
|
What is axonal shearing?
|
when the neuronal cell bodies get torn from their axons
|
|
|
What type of injury does this result in?
|
tiny little focal hemorrhages like petechiae
|
|
What happened here? (what is this pattern and what is the injury?)
|
bleeding at the borders of the middle cranial fossa aka where the sphenoid bone comes up.
brain contusion from moving the brain around and hitting the skull |
|
What is this?
|
meningioma
|
|
|
Where do meningiomas tend to form?
|
around the falx cerebri
|
|
|
How can you find a tumor on CT? (it is hypodense and you must differentiate it from an ischemic stroke)
|
give and wash out gadolinium
or do a T2W |
|
Why does the tumor pick up gadolinium so well?
|
it doesn't have as good of a blood supply so the brain washes out better
|
|
What vessel do these scalp arteries branch off of?
What other structures intersect with these 3 vessels? |
branch off the external carotid
the 3 sentinel nodes for the scalp are located along the orbital-meatal line and these 3 vessels |
