4: CNS Blood Supply Flashcards
anterior circulation pathway
- Right: L ventricle → ascending aorta → brachiocephalic a → R common carotid a → R internal carotid a
- Left: L ventricle → ascending aorta → aortic arch → L common carotid → L internal carotid
posterior circulation pathway
- Right: L ventricle → ascending aorta → brachiocephalic → R subclavian → R vertebral
- Left: L ventricle → ascending aorta → aortic arch → L subclavian → L vertebral
what is the main difference between anterior and posterior circulation?
anterior covers a lot more surface area than posterior
where can you find the anterior cerebral artery (ACA)?
in longitudinal fissure above corpus callosum, along the medial aspect of the frontal and parietal lobes
what are the 2 major branches of the ACA?
- Callosomarginal artery
- Pericallosal artery
how much of the cortex is supplied by the middle cerebral artery (MCA)?
2/3
what are the 3 divisions of the MCA?
- stem
- superior division
- inferior division
what are the lenticulostriate arteries and what structures do they supply?
- arteries branching off of the stem of the MCA
- supply basal ganglia and internal capsule
what is significant about the lenticulostriate arteries?
- When these arteries are involved in a stroke, you’ll likely see motor symptoms
- These arteries are also very sensitive to high BP
what structures are supplied by the superior division of the MCA?
cortex above the sylvian fissure (lateral frontal and parietal lobes)
what structures are supplied by the inferior division of the MCA?
cortex below the sylvian fissure (lateral temporal and parietal lobes)
name all of the structures supplied by the MCA
- Lateral frontal lobe
- Lateral parietal lobe
- Insular cortex
- Medial and lateral temporal lobes
- Subcortical deep structures (basal ganglia, internal capsule, limbic structures)
where does the anterior choroidal artery arise?
arises off ICA near where MCA arises
what structures does the anterior choroidal artery supply?
- Choroid plexus of lateral ventricles
- Optic tract
- Deep structures of telencephalon (posterior limb of internal capsule and portions of basal ganglia)
strokes involving the anterior choroidal will impact what?
CSF
the circle of willis is an anastomosis b/w ____ and ____
ICAs and basilar artery
the circle of willis provides collateral blood flow b/w what 2 circulations of the brain?
R and L anterior and posterior circulations
The complete full-caliber circle of willis is only present in what percentage of people?
34%
what are the components of the circle of willis?
- ACAs
- anterior communicating artery (connects 2 ACAs)
- posterior communicating artery (connects MCAs to PCAs)
- PCAs
where does the posterior cerebral artery (PCA) come from, and where does it go?
arises from basilar a. and travels posteriorly to occiput
what are the superficial branches of the PCA and what do they supply?
- anterior and posterior inferior temporal a’s
- calcarine a’s
- supply medial and inferior occipital lobes + inferior temporal lobes
what are the deep branches of the PCA and what do they supply?
- tuberothalamic, thalamogeniculate, and posterior choroidal a’s
- supply subcortical structures (midbrain, thalamus, subthalamic structures)
what are the 4 branches of the vertebral artery?
- posterior inferior cerebellar artery (PICA)
- anterior spinal artery
- posterior spinal artery (branches off PICA)
- basilar artery
where does the PICA come from and what does it supply?
- Arises at level of medulla
- Supplies lateral medulla and inferior cerebellum
where can the anterior spinal a. be found and what does it supply?
- supplies medial medulla and anterior 2/3 of SC
- sits in ventral median fissure of SC
what does the posterior spinal a. branch off of and what does it supply?
- branches off PICA
- supplies dorsal medial medulla and posterior 1/3 of SC
what are the 7 branches of the basilar artery?
- anterior inferior cerebellar a. (AICA)
- labyrinthine a. (branches off AICA)
- pontine a’s
- superior cerebellar a. (SCA)
- PCA
- paramedian a.
- circumferential a.
where does the AICA arise and what does it supply?
- arises right after basilar a. forms at level of caudal pons
- supplies the lateral caudal pons and cerebellum (small region)
where does the labyrinthine a. arise and what does it supply?
- branches from AICA (in some cases, it arises directly off the basilar)
- enters the internal acoustic meatus to cochlea and vestibular apparatus
what do the pontine arteries supply?
rostral lateral pons
what is the most rostral branch of the basilar artery?
SCA
what does the SCA supply?
- primarily supplies cerebellum
- also supplies some of the rostral dorsolateral pons
what do the paramedian and circumferential arteries supply?
- deeper brainstem structures
- paramedian stay close to midline
- circumferential go more lateral
where do the segmental radicular a’s come from and how do they enter the SC?
- Branch off the ascending thoracic aorta
- Enter SC via nerve roots
what is a notable segmenral radicular a. and what does it supply?
- Great Radicular Artery of Adamkiewicz
- Major supply to lumbar and sacral SC
The venous drainage system functions to remove what 3 things from the brain?
- deoxy. blood
- harmful materials
- circulated CSF
where are the dural sinuses located?
b/w periosteal and meningeal dural layers
what is the main difference b/w veins and sinuses?
sinuses don’t have valves
straight pathway for sinus drainage
Straight, superior, and inferior sinuses (falx cerebri) → confluence of sinuses (occipital lobe) → transverse sinus → sigmoid sinus → internal jugular vein
what drains into the straight sinus?
great cerebral vein and inferior sagittal sinus
cavernous pathway for sinus drainage
Cavernous sinus → superior and inferior petrosal sinuses → internal jugular vein
what drains into the cavernous sinus?
ophthalmic veins
the cavernous pathway is ____ than the straight pathway and it drains the ____ area of the cortex
- shorter
- frontal
name the superficial veins
- superior cerebral
- superficial middle cerebral
- inferior cerebral
- superior anastomotic
- inferior anastomotic
what do the superior cerebral v’s drain?
superior surface of each hemisphere
what do the superior cerebral v’s feed into?
superior sagittal sinus
what do the superficial middle cerebral v’s drain?
lateral surface of each hemisphere
what do the superficial middle cerebral v’s feed into?
cavernous sinus
what do the inferior cerebral v’s drain?
inferior aspect of each hemisphere
what do the inferior cerebral v’s feed into?
cavernous and transverse sinuses
what 2 structures does the superior anastomotic vein connect?
superficial middle cerebral v. to superior sagittal sinus
what 2 structures does the inferior anastomotic vein connect?
superficial middle cerebral v. to transverse sinus
name the deep veins
- anterior cerebral
- deep middle cerebral
- subependymal
- medullary
what does the anterior cerebral vein drain?
deep middle regions of each hemisphere
what does the anterior cerebral vein feed into?
transverse sinus
what does the deep middle cerebral vein drain?
insular cortex and some deep lateral regions of each hemisphere
what does the deep middle cerebral vein feed into?
transverse sinus
name the subependymal veins
- basal veins of Rosenthal
- internal cerebral
- great vein of Galen
what do the basal veins of Rosenthal drain?
medial temporal lobes (parahippocampal gyrus, uncus)
what do the basal veins of Rosenthal feed into?
great vein of Galen
what do the internal cerebral veins feed into?
great vein of Galen
what does the great vein of Galen drain?
thalamus and periventricular regions
what does the great vein of Galen feed into?
sagittal and straight sinuses
