Blood supply Flashcards
What are the types of strokes
- Transient ischemic attack TIA
- Infarction
- hemmorrhage
What are the two systems that supply blood to the brain?
Also what does each system supply
- Anterior: carotid system; supples the cerebrum
- Posterior: vertebral-basilar system; supplies spinal cord, brainstem and cerebellum
What arteries are involved in the posterior circulation?
- Vertebral artery
- basilar artery
- anterior spinal artery
- posterior spinal artery
- posterior-inferior cerebellar artery
- anterior inferior cerebellar artery
- superior cerebral artery
- posterior cerebral artery
Vertebral-basilar system
describe vertebral arteries
- subclavian arteries each form one vertebral artery
- vertebral artery supplies the medulla
- vertebral arteries travel on either side of the cervical spinal cord, enter skull and join to form basilar artery
What does the vertebral artery supply and how can they be damaged?
- brainstem laterally/more anterior (vertebral-basilar system)
- abrupt neck rotation or hyperextension
Prior to vetebral arteries joint to form the basilar artery what are the branches that come off?
- anterior spinal artery
- posterior spinal artery
- posterior inferior cerebrallar artery
What does the anterior spinal artery supply?
also what happens with an infarct
- anterior 2/3 of spinal cord
- medial medulla
- medial medullary syndrome with infarct
What does the posterior spinal artery supply?
what happens with an infarct?
- Posterior 1/3 of spinal cord
- dorsal Medulla lower medulla
- dorsal lateral medulla syndrome
What does the Posterior inferior cerebellar artery supply?
- Posterior inferior cerebellum
- Medulla (dorsolateral)
- Lateral medulla/cerebellar and vestibular issues (wallenberg syndrome)
Basilar artery
- formed by the two vertebral arteries
- Runs from pontomedullary junction to midbrain
what would occur with a blockage of ASA in the medulla?
- medial medullary syndrome
- contralateral weakness
- DCML is damaged slightly
What would occur with an infarct to PICA or vertebral arteries in medulla
- lateral medullary syndrome = wallenberg’s syndrome
- ipsilaterally ataxia, vertigo and sensory changes
Branches of the basilar artery
- anterior inferior cerebrellar artery (AICA)
- superior cerebellar artery
- at end branches to form posterior cerebral arteries (primary source to midbrain)
What does the anterior inferior cerebellar artery supply?
- lateral pons
- anterior, inferior cerebellum
What does the superior cerebellar artery supply?
- superior cerebellar peduncles
- superior cerebellum
What does the posterior cerebral artery supply
-primary source for the midbrain
How does the basilar artery supply the pons
- paramedian branches
- long circumferential arteries
- short circumferential arteries
basilar artery infarct = locked in syndrome
What does the posterior cerebral artery supple
- midbrain
- thalamus
- hippocampus important for memory
- medial, inferior temporal lobe
- occipital lobe
Origin of the carotid system
- aorta
- left side = common carotid artery
- right side = brachiocephalic artery branches into common carotid
- both common carotid arteries branch into internal and exteneral caroitd arteries
Internal carotid
- internal carotid enters the brain through temporal bone of the skull
- branches into anterior cerebral artery, middle cerebral artery
Anterior cerebral artery
supplies
- parts of the caudate
- putamen
- globus pallidus
- internal capsule
- corpus callosum
- anterior, medial frontal lobe
- medial parietal lobe
caudate, putamen, globus pallidus = basal ganglia
Infarct to the anterior cerebral artery
Infarct includes
- frontal lobe dysfunction
- contralateral hemiplegia and hemisensory loss,
- LE>UE-medial sensorimotor cortex affected
- incontinence
What does the middle cerebral artery supply
- Parts of the caudate and internal capsule
- most of lateral hemisphere of cortex
- brocas area is typically on the left
Infarct to the middle cerebral artery
- Very common CVA. Many impairments.
Include:
- Contralateral hemiplegia and hemisensory loss (UE and Face-lateral sensorimotor cortex affected-see next slide),
- aphasia (if lesion in in language dominant side-usually left),
what is the circle of willis
- Connects caroitd and vertebral-basilar systems
- can provide a shunt if there is temporary loss of ciriculation
- important for blood supply to thalamus, internal capsule, and basal ganglia
What arteries form the circle of willlis
- posterior cerebral arteries
- posterior communicating arteries
- internal carotid arteries
- anterior cerebral arteries
- anterior communicating arteries
Aneurysm of the circle of willis
- Anterior communicating artery walls tend to be weaker
- over time this weaker part of the vessel can expand espeically with HTN
- can result in a hemorrhage
Anterior chordoidal
- branch of internal carotid
Supplies:
- choroid plexus (makes CSF
- parts of visual pathway
- putamen
- thalamus
- internal capsule
- hippocampus
Anastomosis
- . communication between cerebral blood vessels by collateral channels.
- Lie within sulci
- Unite branches of the 3 major cerebral arteries end to end (MCA, PCA, ACA)
Watershed CVA
- occurs with severe drops in BP
- maximal BP is required from blood to reach the terminal ends of the arteries where the vessels have the smallest diameter
