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Flashcards in week 4 Deck (168)
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with regards to the central sulcus, where would you find the motor cortex and somaesthetic cortex

Motor cortex in front

somaesthetic cortex behind


what is found on the left hemisphere beside the motor cortex

the motor speech area


what is the path of the anterior cerebral artery

- goes forwards on the medial side near the frontal lobe
- and gives branches around the corner into the lateral side


what does the posterior cerebral artery supply?

posterior part of hemisphere and much of the lower part of the hemisphere


where does the middle cerebral artery come from

the main continuation from the internal carotid artery


what is the path of the middle cerebral artery

Comes off the internal carotid artery and moves laterally and runs into the deep part of the lateral fissure


if the patient has an embolus / blood clot which artery territory is most likely to be affected

If the patient had an embolus / blood clot it is quite likely to go into the territory of the middle cerebral artery


what is the effect on the patient if there is damage to the left cerebral artery

patient likely to be paralysed in the face on the opposite side (in this patient it would be the right side that is affected), lower face and upper limb on right hand side


what artery supplies the lower limn area of the hemisphere

anterior cerebral artery


what artery supplies the area of the motor speech area

left middle cerebral artery


how would a lesion in the left middle cerebral artery affect the motor speech area?

the patient cannot put a speech together and what comes out is unintelligible sounds


what other cortex might be affected by a lesion in the left middle cerebral artery

auditory cortex

but hopefully the other side would be able to maintain some of the hearing


where is the visual cortex found

posterior cerebral cortex
the visual cortex is in this territory on the medial side of the hemisphere


what. is the cranial cavity lined by

dura mater - the outer most layer of the meninges


what can be see around the outside of the floor of the cranial cavity

the cut edge of the vault


what can be seen at the front within the vault

the frontal air sinus
one on each side of the midline


where is bone marrow found

Bone marrow is found in between the inner and outer tables of the skull


what is diploe

Diploe is the spongy cancellous bone separating the inner and outer layers of the cortical bone of the skull.


what is the first cranial nerve

olfactory nerve


how / where does the olfactory nerve appear on the floor of the cranial cavity

Lots of little nerves come from the olfactory epithelium

these little nerves come through the cribriform plate of the ethmoid bone

Soon join the olfactory bulb which has a long tract which leads to the rest of the forebrain


what is the role of the olfactory nerve

Takes information about the sense of smell to the frontal lobe of the brain


what is the bony projection in the anterior cranial fossa called

anterior clinoid process


what is the anterior clinoid process a useful landmark for?

when looking for the optic nerve


what is the second cranial nerve

the optic nerve


what is the path of the optic nerve

The optic nerve is passing from the cranial cavity into the orbit through the optic canal (a little round bony opening)

the optic nerve disappears out of the cranial cavity next to the anterior clinoid process


what can be see a little behind the optic nerve

pituitary stalk


what is the name of the thin layer of dura mater that covers the pituitary gland

diaphragma sellae


what artery can be seen next to the optic chiasm and the pituitary stalk

internal carotid artery


abnormal swellings / aneurysms of the internal carotid can cause what problem

Abnormal swellings / aneurysm (pathological swelling) of the artery can press on the optic chiasm and cause visual disturbances


what is the superior orbital fissure

large comma shaped opening which leads into the orbit)


what is the 3rd cranial nerve

oculomotor nerve


what is the 4th cranial nerve

trochlear nerve


what is the 5th cranial nerve

trigeminal nerve


what does the oculmotor nerve pass through to leave the cranial cavity

superior orbital fissure

runs forward underneath the dura but on top of the bone


where is the trochlear nerve in relation to the oculomotor nerve

Immediately behind the oculomotor, and slightly to the side


what does the trochlear supply

Supplies the superior oblique muscle / muscles in the orbit


what does the trochlear nerve pass through

superior orbital fissure


where is the territory of the middle cranial fossa between

The middle cranial fossa is from the lesser wing of the sphenoid bone to the border of the petrous temporal bone


where is the trigeminal nerve found

Right at the back edge of the middle cranial fossa


where is the trigeminal nerve in relation to the 3rd and 4th cranial nerve

It is found a little bit lateral to where the 3rd and 4th cranial nerve is


what is the path of the trigeminal nerve

Comes from the pons, disappears into a tunnel / cave in the dura called the trigeminal cave


what are the divisions of the trigeminal nerve

- opthalmic
- maxillary
- mandibular


what happens after the trigeminal nerve enters the trigeminal cave

We will find that very soon after going into the trigeminal cave, we would find the trigeminal ganglion and the 3 divisions of the trigeminal nerve


what is the trigeminal ganglino

Flat lacey structure is the trigeminal ganglion and from that the branches come off


what is the path of the opthalmic division

The ophthalmic division goes forwards from the ganglion and disappears out of the cranial cavity into the orbit through the superior orbital fissure, going to supply the skin of the forehead and the front of the skull


what is the path of the maxillary division

quite close to the opthalmic division and running forwards [but not quite so far] is the maxillary division which is going to the foramen rotundum


what is the path of the mandibular division

Out to the side is the mandibular division which is going to the foramen ovale


what is found within the trigeminal ganglion

Cell bodies of many of the sensory neurons of the trigeminal lie within the trigeminal ganglion


what is teh french word for trigeminal neuralgia

Tic Doloreux


what is trigeminal neuralgia

Terrible condition, common enough

Presents as an extremely sharp pain in one of the sensory areas of the trigeminal nerve, quite often the maxillary division

patient experiences this extremely sharp pain on one side of their face

Very difficult to manage

Dental treatment can act as a trigger for it - might come across it

Very often treated medically with a drug called carbamazepine - suppressor drug, anti-epileptic


what is the foramen magnum

large hole in the base of the skull


what is the 6th cranial nerve



what is the clivus

that long slope down to the foramen magnum n the posterior cranial fossa


what is the path of the abducens nerve

Has a very long course

its going to run under the dura over the edge of the petrous temporal bone then forwards to get to the superior orbital fissure where it will leave the cranial cavities

(has a long way deep to the dura before it actually goes out through the bone)


what is the 7th cranial nerve

facial nerve


what is the 8th cranial nerve

vestibulocochlear nerve


where is the 8th cranial nerve found

the 8th is lateral to the 7th and a little bigger than the 7th

Important clinically but not so much as a dental significance


what is the passage way of the 7th and 8th cranial nerves

The passage way these nerves are going into is called the internal auditory / acoustic meatus (bony opening) on their way to an area where the middle ear is (middle ear inside the petrous temporal bone)


where does the 8th nerve go to

the ear


where does the 7th nerve go to

The 7th nerve is going to carry on past CN8, run close to the middle ear then comes out from the base of the skull to supply the muscles of facial expression


what is the 9th cranial nerve



what is the 10th cranial nerve

vagus nerve


what is the 11th cranial nerve

accessory nerve


what is the 12th cranial nerve

hypoglossal nerve


where is the 10th and 11th (cranial root) cranial nerves found

Immediately behind the 9th nerve and lateral to this is the 10th nerve (quite big) and a little 11th nerve (cranial root)


what does the cranial root of CN11 do

the cranial root helps the vagus supply the muscles of the pharynx and larynx


what nerve comes up from the upper cervical cord

the spinal root of the accessory nerve

Spinal root comes from the first 5 cervical segments of the spinal cord

it comes up from the foramen magnum and joins CN9, CN10 and the cranial root of CN11


what does the spinal root of CN11 do

supply the sternocleidomastoid muscle and the trapezius


what do the vertebral arteries join to form

basilar artery


where does the basilar artery run up

the pons


where do the vertebral enter the cranial cavity

foramen magnum


where do the vertebral arteries join together to form the basilar artery

The vertebral arteries are coming through the dura themselves into the view, comes up from below and into the spinal canal, makes its way up through the foramen magnum, up alongside the medulla then when it gets to the pons it joins together to form the basilar artery


what is found in front of the foramen magnum

little rootlets of the hypoglossal nerve


what does the hypoglossal nerve supply

muscles of the tongue


what does the hypoglossal nerve pass into

hypoglossal canal


where is the hypoglossal canal found

sits just in front of the foramen magnum, slightly to the side of the midline

Imagine it is disappearing under the dura


what is found immediately inside the vault of the skull

dura mater


is the dura mater attached to the vault

Slightly attached to the vault but its not firmly attached to the vault

we can take the vault off and push the dura away


what is can be seen in the midline of a coronal section of the head

falx cerebri ~ a large sickle shaped fold


what is inside the falx cerebri

superior sagittal sinus


what is in the superior sagittal sinus

venous blood


what are the 3 layers of meninges

- Dura mater
- Arachnoid mater
- Pia mater


where is the pia mater dound

On the surface of the brain

also found down around the spinal cord (covers the CNS)


describe the pia mater layer

Quite a vascular area - many fine blood vessels in it

Very thin

Follows the surface of the brain everywhere - where there is a gyrus it follows it down into the depths of the sulci


what is the arachnoid layer

middle layer of meninges


where is the arachnoid layer found

Lies immediately deep to the dura

not really attached to the dura, just pushed up against the dura


what is the difference between the meninges layers

Arachnoid and pia are quite soft, flimsy layers

whereas the dura is a very tough layer of collagen


where is cerebral spinal fluid made

inside the ventricles


what is the space between teh arachnoid and pia layer called

sub-arachnoid space


where is the 4th ventricle found

Down at the hind brain, where there is the 4th ventricle, the space between the cerebellum on one side and the pons and the medulla on the othe


how does the CSF escape the brain

escapes from the 4th ventricle at the hind brain


where is CSF found outside the brain

in the sub-arachnoid space
also goes down around the spinal cord as well through the foramen magnum


what is the function of CSF

CSF has biochemical functions

also helps to cushion the brain if someone was to fall and the brain was to move slightly


what gives off the thin cob web like strands found within the sub-arachnoid space

little extensions from the arachnoid mater


where else can these little projections of arachnoid be found

Up at the sinuses, the superior sagittal sinus for example, there are little projections of arachnoid through the wall of the sinus that absorb the CSF - these are arachnoid vili


what are arachnoid villi

The arachnoid villi are little specialisations of the arachnoid that pass through the dura and into the lumen of the superior sagittal sinus


what happens to the CSF around the brain

the CSF around the brain is gradually absorbed into the blood stream of the sinuses by the arachnoid villi


what happens to the CSF around the spinal cord

it is taken away by local lymphatics down in the vertebral region


what else drains the brain

Also get veins draining the brain and heading through the dura as well and opening into the sinus

cerebral vein coming over from the brain into the sinus


what does the middle meningeal artery supply

the vault and to some extent the meninges


where does the middle meningeal artery run

running up between the dura and the bone

the artery is running in a groove at this site of the pterion


what happens if fracture occurs at the pterion

the middle meningeal artery is likely to burst and the blood starts to come out of the vessel between the dura and the bone

enlarges the blood clot / haematoma which then starts to press on the underlying brain

This build up of blood would probably happen over a few hours - patient's conscious level would start to deteriorate and they might become confused

extra dural haemorrhage


what are the 3 types of haemorrhages you get around the brain (extracerebral)

- extradural haemorrhage
- subdural haemorrhage
- subarachnoid haemorrhage


what is an extradural haemorrhage

○ Rupture of the middle meningeal artery
○ Between the dura and the bone
○ Occurs over a few hours with the patient's conscious level deteriorating
○Happen to anyone at any age if they get a fracture to the skull


what is a subdural haemorrhage

○ Involves the cerebral veins

○ Tends to happen in the elderly with a small blow to the head - tissues aren't quite as resilient as they were before so even a little bump of the head could be enough to move the brain

○ Cerebral vein is going from the brain through the dura to the superior sagittal sinus
§ The soft vein is attached to the firm dura - movement is likely to damage this site, can actually pull the vein off just as it is going into the dura

○ Arachnoid is immediately internal to the dura so blood starts to build up between the arachnoid and the dura

○ Blood tends to ooze out slowly and you get an enlarging blood clot between the dura and the arachnoid
§ Because it is venous blood it is not coming out as quickly as arterial blood does in an extradural haemorrhage

○ Tends to occur over a few days / weeks


what is a subarachnoid haemorrhage

○ Bleeding of the cerebral arteries still at base of brain
○ Around the area of the circle of Willis you might get a little aneurysm which is known as a Berry aneurysm

○ sometimes in middle life people get a little pathological swelling somewhere on the arteries in this area (often where there is a bifurcation of an artery)
Can burst and give a subarachnoid haemorrhage

○ Can either be caused by trauma or can occur spontaneously

○ Massive bleed into the subarachnoid space, only on the underside of the brain
§ Arterial blood

○ Patients often have a very severe headache in the moments before they go unconscious or sometimes people go unconscious immediately - well recognised cause of sudden death

○ Caused by the pathological process that causes a localised weakness of the artery (aneurysm)


what part of the brain overlies the foramen magnum



what is the layer of dura that covers the cerebellum called

tentorium cerebelli

has a gap in it for brainstem to pass down


where does the superior sagittal sinus comes down

where the falks meets the tentorium cerebelli

check diagram lol cos i think ive taken this down wrong

but i think the superior sagittal sinus runs within the falks to the back of the skull?


what happens to the blood in the superior sagittal sinus when it gets to the tentorium cerebelli

the blood in it swings to the right and the name of the sinus changes to the right transverse sinus


where does the right transverse sinus run

Right transverse sinus runs from the place where the tentorium is meeting the side wall

makes a groove on the inside of the bone of the skull


what happens to the right transverse sinus once it reaches the front of the postrerior cranial fossa

it changes direction again and forms an 'S' shaped bend

it is now called the sigmoid sinus


where is the sigmoid sinus found

Deep to the dura of the floor of the posterior cranial fossa, down under the cerebellum


where does the sigmoid sinus exit the skull

at the jugular foramen


what else leaves the skull at the jugular foramen



what does the blood run into runs it leaves the skull at the jugular foramen

once the blood leaves the skull at the right jugular foramen it becomes the right internal jugular vein


where does the straight sinus run

the straight sinus which is running in the place where the falks is meeting the tentorium


where does the straight sinus go

it comes round and swings to the left and becomes the left transverse sinus


what happens to the left transverse sinus

The left transverse sinus then forms an 'S' shaped bend (sigmoid sinus) and goes down to the jugular foramen as well


what is the little connection between the straight sinus and the superior sagittal sinus called

the confluence of sinuses


where does the transverse sinus run

Transverse sinus runs fairly horizontally where the tentorium is meeting the side wall


in the middle cranial fossa, what sinus is formed when 2 opthalmic veins join together

cavernous sinus


how is the cavernous sinus drained

drained by little sinuses which run along the edge and down

these are called the superior and inferior petrosal sinuses


where does the cavernous sinus receive blood from

Cavernous sinus is receiving lots and lots of blood from the orbit, has connections to the face through the orbit so there is lots of venous blood coming in the ophthalmic veins in the orbit which drains into the cavernous sinus


is the cavernous sinus a single lumen

There are lots of spaces within the cavernous sinus,

it is not a single lumen, instead

there are lots of little lumens within


how fast is the blood flow within the cavernous sinus

there is a very slow blood flow through the cavernous sinus


what sinus travels to the sigmoid sinus from the middle cranial fossa

The petrosal sinuses go down to the sigmoid sinuses and so goes out into the internal jugular vein
(superior and inferior petrosal sinuses)


what is the vein that comes out the side of the cavernous sinus

sphenoidal emissary vein


where does the sphenoidal emissary vein go

goes through the base of the skull

often goes through the foramen ovale but sometimes it has its own hole


what problems can patients get in the cavernous sinus

thrombosis of the cavernous sinus (the blood inside it clots)


why can bacteria multiply from infection within the cavernous sinus

because the blood flow is slow


what happens if there is bacteria multiplying within the cavernous sinus

blood cannot get back from the orbit


what are features of cavernous sinus thrombosis

swollen eye and fever


what is the name of the little plexus of veins from behind the upper jaw

pterygoid venous plexus


can dental sepsis cause cavernous sinus thrombosis


The bacteria from an abscess of a tooth might get into the blood of the pterygoid venous plexus

this plexus connects through the little sphenoidal emissary vein into the cavernous sinus

It is possible that bacteria from the upper jaw area to make their way through the veins into the cavernous sinus and allow bacteria to multiply and the blood to clot

Thrombosis stops the blood flowing back from the eye so the patient again has a fever and a swollen eye


what colour do bones appear in an MRI scan

they are radiopaque


what is periosteum

thin membrane immediately on surface of bone


what would you expect to see in the cut surface of the vault

- Part in middle = diploe (spongy bone, rich in bone marrow)

- Outer zone = outer table of the skull (cortical bone)

- Inner zone = inner table of the skull (cortical bone)


what happens in paget's disease

bone remodelling is out of control

skull can look more bulging in this disease
can affect any part of the skeleton


what is the tentorium cerebelli

fold of dura mater between the cerebrum and the cerebellum


what bony projection does the falx cerebri attach to

crista galli


where does the great cerebral vein go into

straight sinus


what is the middle crania fossae

depression formed by sphenoid and temporal bones


what is the central part of the middle cranial fossae occupied by

pituitary gland


what do the lateral parts of the middle cranial fossae contain

temporal lobes of the cerebral hemispheres of the brain


where do the transverse sinuses begin

at the confluences of sinuses


where do the transverse sinuses pass

passes laterally across occipital bone in the attached margin of the tentorium cerebelli


where do the transverse sinuses drain into

sigmoid sinus


where does the transverse sinuses receive from

- inferior cerebellar veins
- inferior cerebral veins
- posterior temporal
- occipital diploic veins
- superior petrosal sinus (into sigmoid sinus)


where is the straight sinus found

site of attachment between falx cerebri and tentorium cerebelli


where does the straight sinus pass

passes down and back to enter confluence of sinuses then continues as left transverse sinus


where does the straight sinus receive from

superior cerebellar veins


where does the superior petrosal sinuses run

over the groove of the upper border of petrous parts of temporal bonea

passes back and out from cavernius sinus to transverse sinus at junction with sigmoid sinus


where is the inferior petrosal sinuses found

at lower border of petrous bone, groove on petro-occipital suture


where does the inferior petrosal sinuses pass

passes from postero-inferior side of cavernous sinus and terminates at sigmoid sinus / jugular foramen


where does the tentorium cerebelli lie

between cerebellum and occipital lobes of cerebral hemispheres


where does the lateral edges of the tentorium cerebelli attach

attach to occipital bone
encloses the transverse sinuses


where are the anterior lateral edges of the tentorium cerebelli attached to

attached to the upper borders of the petrous parts of temporal bones and contain the superior petrosal sinuses


where is the free margin of the tentorium cerebelli found

continues anteriorly to get attachment to anterior clinoid processes


what is the falx cerebri

sickle shaped fold of dura that lies along the median sagittal plane in the longitudinal cerebral fissure between 2 cerebral hemispheres


what does the falx cerebri separate

separates 2 lobes of cerebellum


where does the falx cerebri attach anteriorly

the crista galli of the ethmoid bone


where else does the falx cerebri attach to the skull

attachment to the skull continues supero-posteriorly along the margins of the superior sagittal sinus to the internal occipital protuberance


what happens to the falx cerebri at the posterior and inferior limits

it is continuous with the tentorium cerebelli


where does the inferior sagittal venous sinus run

in the free border of the falx cerebri


where does the straight sinus run

runs along the falx cerebri's junction with the tentorium cerebelli


what is teh anterior cranial fossae

depression fromed by frontal, ethmoid and sphenoid bones


what is the anterior cranial fossae occupied by

frontal lobes of the cerebral hemispheres of brain