Vascular Anatomy of CNS Flashcards
what is the source of bs of the brain
2 internal carotid arteries and 2 vertebral arteries
how is the circle of Willis formed
mag aanastomose yung branches ng ICA and VA
where does the ICA originate
from the bifurcation of the common carotid artery
where does the ICA enter the skull
via carotid canal
from its origin sa common carotid the ICA will ascend in ________
ascend in front of transverse process of upper 3 cervical vertebrae
after entering the skull. the ICA runs ________
then runs horizontall w/in cavernous sinus
after the cavernous sinus the ICA will _____
pierce the dura to begin the its subarachnoid course
after it pierces the dura the ICA then ______
turns post medial to lateral sulcus where it divides into the ACA and MCA
what is the carotid siphon
intracavernous and cerebral segments bcs of the S-shaped configuration
in the cavernous sinus the ICA lies close to _______
middle wall adjacent to CN VI
what are the branches of the cerebral portion of the ICA
ophthalmic
anterior choroidal
anterior cerebral
middle cerebral
posterior communicating
discuss the path of the ophthalmic artery
branches from ICA sa cavernous sinus
tas enters the orbit through optic canal below and lateral the optic nerve
what does the ophthalmic artery supply
optic nerve and gives rise to central artery of the retina
what does the terminal branches of the ophthalmic artery supp
frontal area of scalp, ethmoid and frontal sinuses and dorsum of the noise
discuss the origin of the anterior choroidal artery
emerges after ICA enters cavernous sinus and will pass ventral to the optic tract
what does the anterior choroidal artery supply
optic tract
cerebral peduncles
LGB
posterior limb of the internal capsule
tail of the caudate
uncus
amygdala
anterior hippocampus
choroid plexus of the temporal horn
sometimes the globus pallidus
discuss the origin of the ACA
originates from the ICA lateral to the optic chiasm
after passing the optic chiasm the ACA will ______
course dorsal sa optic nerve to reach inter hemispheric fissure
after reaching the inter hemispheric fissure the ACA will _______
curve around the corpus callosum and will continue as the pericallosal artery
what joints the 2 ACAs
as the 2 ACAs approach the interhemispheric fissure they are joined by the Acomm
what does the cortical branches of the ACA supply
entire medial surface of cortex until parieto-occipital sulcus and strip of cortex sa anterior lateral part
it is the main branch of the ICA
middle cerebral artery
what does the central branches of the ACA supply
pierces anterior perforated substance and helps supp parts of lentiform. caudate nuclei and internal capsule
what are the 4 segments of the MCA
M1 - sphenoidal
M2 - insular
M3 - opercular
M4 - cortical
where is the M1 - sphenoidal segment
posterior and parallel to sphenoid ridge
where is the M2 - insular segment
sa insula
where is the M3 - opercular segment
courses over frontal, parietal and temporal opercula
where is the M4 - cortical segment
spreads over the cortical surface
the MCA courses within the _____
sylvian fissure
what does the MCA supply
limited to the inferior margin of cerebral hemisphere and the inferior surfaces of frontal and temporal lobes
basta gitna ng lateral part
what does the cortical branch supply
entire lateral surface of hemisphere
except anterior strip kasi sa ACA yun, occipital pole and inferolat nun bcs sa PCA yun
entire motor area excepts sa legs
where dose the Pcomm come from
runs post above the oculomotor nerve to join the PCA
what does the Pcomm connect
ICA w PCA
what does the PComm supply
genu and anterior part of the
posterior limb of the internal capsule
anterior part of the thalamus
parts of the hypothalamus and subthalamus.
where does the vertebral artery come from
arises from the subclavian artery
the VA ascends with in the _____
foramina of the transverse
processes of the upper 6 vertical vertebrae
after ascending the VA (intraosseous seg) will ______ and will form the _____
intraosseous segment will curve backward around the lateral mass of atlas
and form atlantoaxial segment
after the atlas the VA will _____
enter cranium via foramen magnum
forming intracranial segment
where does the VA lie w/in the cranium
lie on inferior surface of medulla
what is formed when 2 VAs join
joined at caudal end of pons to form basilar artery
what are the branches of the VA
posterior spinal
anterior spinal
posterior inferior cerebella
meningeal branches
what does the meningeal branches supply
supply meninges of the posterior fossa including the falx cerebelli
discuss the path of the posterior spinal artery
2 posterior spinal arteries pass caudally over the medulla and posterior of SC close sa posterior roots
what reinforces the posterior spinal artery
radicular arteries that enter VC through IV foramina
what does the anterior spinal artery supply
medullar pyramids and paramedian medullary structures
anterior 2/3 of SC
what does the posterior spinal artery supp
posterior aspect of medulla below obex and post column and posterior horns of SC
discuss the path of the anterior spinal artery
starts as 2 vessels that joint to form a single artery
descends on ventral of medulla into anterior median fissure of SC
what reinforces the anterior spinal artery
radicular arteries that enter VC through IV foramina
discuss the path of the posterior inferior cerebellar artery
PICA follows an s-shaped course over olive and inferior cerebellar peduncle
origin of basilar artery
formed by union of 2 VA at caudal end of pons
what does the PICA supply
inferior cerebellum
dorsolat of medulla
choroid plexus of 4th vent
part of deep cerebellar nuclei
what are the main branches of the basilar
paramedian penetrating fibers
short circumferential arteries
long circumferential arteries
PCA
discuss the path of basilar artery
runs in pontine groove on ventral of pons and terminates at rostral end to give 2 PCA
what does paramedian penetrating fibers supply
paramedian zone of the basilar portion of the pons and adjacent pontine tegmentum
what does short circumferential arteries supply
anterolateral and posterolateral parts of the pons
what are the long circumferential arteries from basilar
Auditory (labyrinthine) artery
Anterior inferior cerebellar artery (AICA)
Superior cerebellar artery (SCA)
what does Auditory (labyrinthine) artery supply
supplies inner ear and root fibers of facial nerve
what does Auditory (labyrinthine) artery join
sumasama sa CN VII and CN VIII into internal auditory meatus
what does the AICA supp
inferior cerebellum
brachium pontis and restiform body
tegmentum of lower pons and upper medulla
discuss the path of SCA
winds around the cerebral peduncle
what does SCA supply
sup cerebellum
part of dentate nuc
brachium pontis and conjunctivum
tegmentum of upper pons
inferior colliculus
what does the cortical branch of the PCA supply
inferolateral and medial surfaces of temporal lobe
lateral and medial surfaces of occipital lobe
visual cortex
what does the central branch of the PCA supply
pierce the brain substance to supply
parts of thalamus and lentiform nuc and midbrain
pineal and medial geniculate bodies
what does the choroidal branch of the PCA supply
enters inferior horn and lateral vent and supp
choroid plexus of lat and 3rd vent
discuss the path of the posterior cerebral artery
curves laterally and backward around the midbrain and is joined by PComm
what supplies the corpus striatum and internal capsule
medial and lateral striate central branches of MCA
what supps the thalamus
branches of PComm, basilar and PCA
what supps the midbrain
PCA, SCA and basilar
what supps the medulla
VA, ant and post spinal, PICA, basilar
what supps cerebellum
SCA, AICA, PICA
what makes up the circle of willis
proximal portions of the ACA, MCA, PCA connected by AComm and PComm
whre does the circle of willis lie
in the interpeduncular fossa
around infundibulum of pituitary and optic chiasm
significance of circle of willis
important anastamotic channel betw ICA at vertebrobasilar systems
where does the veins of brain lie
in subarachnoid space
describe the structure of the veins of the brain
no muscular tissue and valves and has very thin walls
what is the path of brain veins
pierces arachnoid matter and meningeal layer of dura and drain into cranial venous sinus
discuss the path of the superficial cerebral veins
pass upward over the lateral surface of the cerebral hemisphere and
what do superficial cerebral veins drain
dorsolat and dorsomed surfaces of hemisphere
where do superficial cerebral veins enter
enters superior sagittal sinus
most prominent superficial vein and what does it connect
superior anastomotic vein of Trolard
connects sup and middle groups of veins
discuss the path of superficial middle cerebral veins
runs along the sylvian fissure
what do superficial middle cerebral veins drain
drains inferolat surface of hemisphere
where do superficial middle cerebral veins open into
cavernous sinus
what do inferior cerebellar veins drain
inf surface of hemisphere
where do inferior cerebellar veins open into
cavernous and transverse sinuses
what connects middle and inferior groups of inferior cerebral veins
inferior anastomotic vein of Labbe
where does the inferior anastomotic vein of Labbe cross
crosses the temporal lobe 5cm behind its tip
what drains the medial surface of the hemisphere and where does the veins open into
number of veins that open into the sup and inf sagittal sinuses, basal vein and great cerebral vein of Galen
what consists the external/superficial venous system
superficial cerebral, superficial middle cerebral and inferior cerebral veins
what forms the deep venous system
2 internal cerebral veins are formed by the union of thalomostriate vein and choroid vein at IV foramen
discuss the path of internal cerebral veins
run post in the tela choroidea of 3rd vent and unite under the splenium of corpus callosum
what is formed at the splenium of the corpus callosum
internal cerebral veins unite there to form great cerebral vein
where does the deep venous system empty
straight sinus
what drains the midbrain
veins that open into the basal or great cerebral veins
what drains the pons
basal vein, cerebellar veins or neighboring venous sinuses
what drains the medulla
spinal veins and neighboring venous sinuses
what drains the cerebellum
great cerebral vein or adjacent venous sinuses
what lines cerebral dural venous sinuses
by the endothelium and devoid of valves
loc of cerebral dural venous sinuses
between the periosteal and meningeal layers of the dura
what is the function of cerebral dural venous sinuses
low-pressure channels for venous blood flow back to the systemic circulation
where does the sup sagittal and inf sagittal sinus lie
superior and inferior portions of the falx cerebri
where do superior cerebral veins drain into
superior and inferior sagittal sinuses
how is the straight sinus formed
inferior sagittal sinus is joined by the Great vein of Galen to form the straight sinus
where is the straight sinus loc
junction of the falx cerebri and tentorium cerebelli
where does the straight sinus drain into
confluence of sinuses
what is the path of the blood drained from the straight sinus
pass laterally and forward in a groove in the occipital bone
after the occipital bone the straight sinus will ______
sa occipitopetrosal junction they curve downward and backward as the sigmoid sinus
where does the sigmoid sinus drain into
internal jugular vein
______ connects the confluence of sinuses to the marginal sinus at the _______
occipital sinus
foramen magnum
into connects the petrosal vein and transverse sinus into the cavernous sinus
superior petrosal sinus
where does the sup petrosal sinus lie
in the dura at the anterior border of the tentorium cerebelli
it joins the cavernous sinus to the jugular bulb
inferior petrosal sinus
inferior petrosal sinus extends _______
extends between the clivus and petrous bone
describe the structure of cerebral arteries
thinner wall and absent external elastic laminae
has astrocytic process and perivascular reticular consisting of arachnoid trabeculae
what surrounds cerebral cappilaries
surrounded by perivascular glial (astrocytic) processes
significance of blood-brain barrier
isolates the brain tissue from the rest of the body
what forms the blood-brain barrier
formed by the tight junctions that exist between the endothelial cells in the capillary beds
describe cerebral veins
thinner walls and devoid of valves and muscle fibers
function of cerebral veins
allows reversal of blood flow during occlusion
extrinsic factors that affect cerebral circulation
systemic BP
blood viscosity
vessel lumen
intrinsic factors that affect cerebral circulation
auto regulation and biochemical factors
what regulates systemic BP
by baroreceptors located at the aortic arc and carotid sinus
exp the effects of systemic BP to CBF
little changes will not affect it but i
Decrease in CBF if SPB <200mmHg or DBP >110-120mmHg
CO2 – hypercapnia = vasodilation =
increase CBF
Oxygen – hypoxia = vasodilation =
increase CBF
explain autoregulation
Smooth muscles in small cerebral arteries and arterioles change their tension in response to intramural pressure to maintain a constant flow despite changes in perfusion pressure
nerve supp of cerebral arteries
sympathetic postganglionic nerve fibers from superior cervical sympathetic ganglion
+ vasoconstriction
what is formed from spinal cord arteries
2 posterior spinal arteries and 1 anterior spinal artery
what reinforces spinal arteries
by small segmentally arranged arteries
where does the small segmentally arranged arteries come from
from arteries outside the vertebral column and enter the vertebral canal through the intervertebral foramina
spinal cord arteries anastomose on _____
surface of the cord
spinal cord arteries send out branches on
into the substance of white and gray matter
origin of posterior spinal arteries
directly from the vertebral arteries (or indirectly from the PICA)
path of posterior spinal arteries
Descends on the posterior surface of the spinal cord close to the posterior nerve root
posterior spinal artery branches to ______
gives off branches that enter the substance of the cord
posterior spinal artery supplies
posterior ⅓ of the spinal cord
explain significance of “small in upper thoracic ang posterior spinal artery
First 3 thoracic segments are vulnerable to ischemia
origin of anterior spinal artery
by union of 2 vertebral arteries
path of anterior spinal artery
Descends on anterior surface of the spinal cord within the anterior median fissure
anterior spinal artery supps ?
anterior 2/3 of the spinal cord
explain the sig of upper and lower thoracic segments have small ASA
T4 and L1 are particularly susceptible to ischemia
At each intervertebral foramen, the
________ are reinforced by small segmental arteries on both sides.
longitudinally running posterior and anterior spinal arteries
Each segmental artery gives rise to ______
anterior and posterior radicular arteries
anterior and posterior radicular arteries accompanies ______
anterior and posterior nerve root to the SC
origin of the segmental arteries
Branches of deep cervical, intercostal and lumbar arteries (outside the vertebral column)
_____ anastomose with ASA and PSA
Feeder arteries
Great anterior medullary artery of Adamkiewicz arise from?
aorta in the lower thoracic or upper lumbar vertebral levels
Great anterior medullary artery of Adamkiewicz supp?
unilateral (most on L); may be a major source of blood supply to the lower ⅔ of the SC.
where does spinal veins drain mainly
into the intervertebral venous plexus
aside from the intervertebral venous plexus where do spinal veins drain into
longitudinal channels that communicate superiorly within the skull with the veins of the brain and the venous sinuses
