Brain and spinal cord - week 1 dry room Flashcards
1
anterior cerebral arteries
2
anterior communicating arteries
3
opthalmic arteries
4
internal carotid arteries
5
middle cerebral artery
6
posteiror communicating artery
7
posterior cerebral artery
8
superior cerebellar artery
9
basilar artery
10
labyrinthine artery
11
anterior inferior cerebellar artery
12
posterior inferior cerebellar artery
13
vertebral artery
14
anterior spinal artery
fomr which arteries do the left and right vertebral arties arise?
subclavian arteries
at what vertebral level do the left and right internal carotid arteries arise?
C3/4
how is the basilar artery formed and which part of the brainstem is it most closely related to?
when the 2 vertebral arteries join
PONS
what arteries complete the posterior of the Cirlce of Willis by linking the internal carotid arteries to the posterior cerebral arteries?
posterior communicating artery
which artery completes the anterior Circle of Willis by linking the anterior cerebral arteries?
anterior communicating artery
in which fissure/groove/sulcus of the brain do the following travel:
anterior cerebral artery
middle cerebral artery
posteiror cerebral artery
anterior cerebral artery - longitudinal fissure
middle cerebral artery - lateral sulcus/fissure
posteiror cerebral artery - transverse fissure
what artery is responsible for supplying each area?
blue - anterior cerebral artery
red - middle cerebral artery
green - posterior cerebral artery
what supplies the primary motor cortex?
middle cerebral artery and a small bit of cerebral artery
what supplies the primary sensory area?
middle cerebral artery
what supplies the primary visual cortex?
calcarine branch of the posterior cerebral artery
what supplies the primary auditory area?
middle cerebral artery
what supplies the area of olfaction?
anterior cerebral artery
which parts of the brain does the vertebro-basilar system supply?
brain stem
cerebellum
occipital lobes
which artery runs immediatley superior to the superior cerebellar arteries?
posterior cerebral artery
which cranial nerve emerges form jsut above the superior cerebellar artery?
trochlear nerve (CN IV)
aneurysms of the posterior cerebral artery are common at this location, often resulting in palsy of the cranial nerve III emerging just below
what are the clinical manifestations of palsy of this cranial nerve?
ptosis - dropping of upper eye lid
eyeballd abducted and pointing down
no pupillary reflex
no accomiidation of the lens
what is a carotid sinus?
this is a dilation located on the terminal part of the common carotid artery (or the proximal part of the ICA). It is a pressure receptor which monitors the flow of blood to the head, including the brain. Sensory nerves from the carotid sinus run in the glossopharyngeal nerve and vagus nerve
what is a carotid body?
This is an area on the posterior wall of the terminal part of the common arotid artery in the neck. It contains chemoreceptors which are sensitive to low oxygen levels (anoxia). Sensory nerves from these receptors run in the glossopharyngeal nerve. Detection of anoxia will stimulate increased heart rate, respiration rate and blood pressure
what are sympathetic motor nerves?
from the superior cervical ganglion and form a plexus around the internal carotid artery. This plexus enters the skull, with the artery, through the carotid canal, and continues along the main branches of the internal carotid artery
the brain is drained by veins which drain into ______________
dural venous sinuses
where are these sinuses present?
between the periosteum and the cranial dura
what 2 groups are cerebral veins often divided into and what is an example?
superficial and depp groups
an example of the deep group is the great cerebral vein (of Galen)
a
opthalmic canal/sphenoparietal sinuses
b
cavernous sinus
c
petrosal sinus: superior + inferior
d
sigmoid sinus
e
transverse sinus
f
confluence of sinus
g
straight sinus
h
inferior saggital sinus
i
superior saggital sinus
into what vein in the neck do these dural venous sinuses drain into?
IJV
through which foramen in the skull does the vein you have named above pass?
jugular foramen
the veins in the brain and cranial venous sinuses do not have valves to prevent backflow of blood form outside the cranium back into the cranium
what are some important connections between intracranial venous sinuses and extracranial venous network?
- superior opthalmic vein drains into the cavernous sinus within the cranial cavity. On the outside of the cranial cavity it is continuous with the facial vein
- emissary veins are small veins that connect the cranial venous sinuses with the diploe of the skull containing the blood sinuses in the bone marrow of the diploe which in turn are continuous with the veins in the superficial fascia overlying the outer part of the skull and scalp
- the inferior petrosal sinuses lie at the base of the brain and are connected to each other (left and right) by the basilar sinus. This small sinus also communicates inferiorly with the internal vertebral sinus
what vein drains into the cavernous sinus?
opthalmic vein
what structures in the base of the skull is closely related ot the cavernous sinus?
optic chiasm
CN III, IV, V1, VI
Pituitary gland
ICA
cavernous sinus thrombosis (CST) is a clinical condition due to a spreading of infection form the nse, sinuses, ears or teeth. Reflect on how infections may spread to it from these regions
opthalmic veins (valveless)
CST results in bulging eyes and a loss of vision, why?
and also paralysis of the nerves coursing through it
increased IOP
name all the grooves in the skull from venous sinuses
a - occipital
b - superior saggital
c - cavernous
d - sigmoid
e - transverse
f - confluence of sinuses
branches from which arteries fuse to form the anterior spinal artery?
veretebral arteries
which arteries are the posterior spinal arteries branches of?
mainly posterior inferior cerebellar artery but can be vertebral artery
what is the internal vertebral (epidural) venous plexus?
the longitudinally orientated anterior and posterior spinal veins communicate freely with rach other and join to form the internal vertebral venous plexus which lies in the epidural space
this plexus of veins passes superiorly within the vertebral canal through the foramen magnum to communicate with the dural sinuses and veins within the skull
the internal vertebral venous plexus also communicates with the external vertebral venous plexus on the external surface of the vertebrae
what fluid circulates in the subarachnoid space?
CSF
what other structes are present in the subarachnoid space?
blood vessels
what is the midline vetical sheet of dura called and what is the horizontal sheet of dura called?
falx cerebri
tentorium cerebeli
what structures doed the falx cerebri separate?
cerebral hemispheres
to which bony structures the falx cerebri attach anteriorly?
crista gali of the ethmoud bone and the clinoid processes (anterior + posterior)
which dural venous sinus runs within the upper border of the falx cerebri?
superior sagittal sinus
which dural venous sinus runs within the lower border of the falx cerebri?
inferior saggital sinus
what structures lie on either side of the tentorium cerebelli?
cerebellum and occipital lobes
to what bony points does the anterior edge of the tentorium cerebelli attach to?
petorus part of the temporal bone
clinoid processes of the pshenoid bone
which dural venous sinus runs along the attachment of the falx cerebri to the tentorium?
straight sinus
what is the dural fold that seperates the 2 cerebellar hemispheres called?
falx cerebelli
what is the fold of sura that surrounds the two cerebellar hemispheres called?
diaphragma sellae
what is the arterial supply of dura mater?
form branches of numberous arteries including the ICA, branches of the ECA and vertebral arteries
one of the clinically important meningeal arteries in the middle meningeal artery
this is a specific branch of the maxillary artery that supplies the dura mater
through which foramen in the skull does it enter the cranial cavity?
foramen spinosum
which artery is the maxillar artery a terminal branch of and within which glandular strucutre is it give off?
ECA
parotid gland
ventricles are interconnected spaces/cavities that lie within the brain
the central canal of the spinal cord is a continuation of the ventricular system within that structure
what embryological structures are these spaces formed from?
hole in the neural tube
what part of the brain do the following lie within?
anterior horn of lateral ventricle
body of lateral ventricle
posterior horn of lateral ventricle
inferior horn of lateral ventricle
interventricular foramen (foramen of munro)
3rd ventricle
cerebral aqueduct (of the midbrain)
4th ventricle
anterior horn of lateral ventricle - frontal lobe
body of lateral ventricle - parietal lobe
posterior horn of lateral ventricle - occipital lobe
inferior horn of lateral ventricle - temporal lobe
interventricular foramen (foramen of munro) - between frontal lobe and diencephalon
3rd ventricle - diencephalon
cerebral aqueduct (of the midbrain) - midbrain
4th ventricle - between PONS + medulla infront and the cerebellum at the back
what is the name given to the specialised strucutres that lie in the ventricles that generate CSF?
choroid plexus
how does CSF pass into the subarachnid space form the 4th ventricle?
three small foramina to subarachnoid space
(cirlce in diagram)
at which location is the CSF resorbed back into the general circulation?
arachnoid villi in saggital sinus
what makes the identations on either side of the superior saggital sinus?
arachnoid villi/granulations
if circulation of CSF is restricted then increase of inracerebral pressure. In infancy, congenital defects in circulation lead to a progressive enlargement of the head and a reciprocal reduction in cerebral matter. This conditions is known as hydrocephalus and can occur in isolation or as part of spina bifida. This is a very treatable conditions using a tube known as a shunt to redirect the fluid out of the cerebral circulation into the deep venous system. In later life disruption of CSF circulation can also be associated with trauma and will not result in the enlargement of the head. What do you think would result in with respect to the brain?
increases pressure on the brain and pushes it through the foramen magnum resulting in coning causing constriction of the medulla
