Lecture 6 - Blood Supply of the Brain

Question 1

What fissure/sulci does the ACA run through?

Answer 1

Longitudinal fissure

Question 2

What fissure/sulci does the MCA run through?

Answer 2

lateral sulcus

Question 3

What fissure/sulci does the PCA run through?

Answer 3

transverse fissure

Question 4

What percentage of our body weight is the brain?

Answer 4

2%

Question 5

What percentage of blood supply goes to the brain?

Answer 5

20%

Question 6

Does gray or white matter have more blood vessels? Why?

Answer 6

Gray matter more than white
- gray matter has the cell bodies, neurons, glia and therefore needs more energy and more blood supply
- White matter contains axons, which need less energy/blood supply

Question 7

What two arteries supply the brain?

Answer 7

• anterior division: internal carotid artery
• posterior division: vertebral-basilar artery (ascends through transverse foramen of vertebrae into foramen magnum)

Question 8

What supplies the anterior division of the brain?

Answer 8

the internal carotid artery

Question 9

What supplies the posterior division of the brain?

Answer 9

the vertebral-basilar artery

Question 10

What are some of the major branches of the internal carotid artery ?

Answer 10

• anterior cerebral artery
• middle cerebral artery
• opthalamic artery
• anterior choroidal artery
• posterior communicating artery

Question 11

What is important about the opthalamic artery in the anterior brain?

Answer 11

first branch of the internal carotid, follows the optic nerve through the optic canal for the eye

Question 12

What is important about the antrior choroidal artery?

Answer 12

from IC, forms choroid plexus in ventricles for CSF

Question 13

What is important about the posterior communicating artery?

Answer 13

forms an anatomoses with the basilar artery and connects anterior brain blood supply with posterior brain blood supply

Question 14

What does the vertebral basilar artery split into?

Answer 14

• vertebral artery (2 on each side)

Question 15

Why is the vertebral artery at the C6 transverse foramina important?

Answer 15

it crosses over only at C6, which is where dislocations or disc herniations can happen, which can compress the vertebral artery leading to nausea, vomiting, etc.

Question 16

What does the vertebral artery form?

Answer 16

• anterior spinal artery
• posterior inferior cerebellar artery (PICA)
  -> forms the posterior spinal artery

Question 17

Why is PICA important?

Answer 17

important to cerebellar functions
- from the vertebral artery

Question 18

What does the vertebral-basilar artery give off?

Answer 18

the basilar artery at the pontomedullary junction

Question 19

What does the basilar artery give off?

Answer 19

• anterior inferior cerebellar artery (AICA)
• pontine arteries
• superior cerebellar artery (SCA)
• posterior cerebral artery (PCA)

Question 20

What is important about the PCA?

Answer 20

1st CN oculomotor nerve runs through the SCA and PCA, if an aneurysm happens here it will compress the nerve!

Question 21

A patient fractured the basal neurocranium around the jugular foramen. Which nerves coursing through would be compromised?

Answer 21

CN IX, X, and XI

Question 22

A patient fractured the basal neurocranium around the foramen ovale. Which nerve coursing through would be compromised?

Answer 22

trigeminal nerve - mandibular branch

Question 23

What is the circle of willis?

Answer 23

9 members, anastomosis of anterior/posteiror divisions

Question 24

What are the 9 members of the circle of willis?

Answer 24

• anterior communicating artery
• ACA x 2
• Internal carotid artery x2
• Posterior communicating artery x2
• PCA x2

Question 25

What artery is NOT involved in the circle of willis?

Answer 25

the MCA

Question 26

What percentage of the population has a typical circle of willis?

Answer 26

only 30%, huge veriations

Question 27

Where is the ACA?

Answer 27

in the longitudinal fissure

Question 28

What does the ACA supply??

Answer 28

the medial/supeiror frontal and parietal lobes plus the cingulate gyrus

Question 29

What happens with a R ACA stroke?

Answer 29

the Left lower limb compromised

Question 30

Where does the MCA run?

Answer 30

in the lateral sulcus

Question 31

What does the MCA supply?

Answer 31

the lateral and inferior frontal/perietal lobes, & superior temporal lobe

Question 32

What can an MCA stroke cause?

Answer 32

aphasia

Question 33

Where does the PCA run?

Answer 33

in the transverse fissure

Question 34

What does the PCA supply?

Answer 34

the inferior temporal lobe and occipital lobe

Question 35

What basal nuclei does the ACA branch supply?

Answer 35

the nucleus accumbens and caudate

Question 36

What basal nuclei does the MCA branch supply?

Answer 36

the putamen and caudate

Question 37

What basal nuclei does the PCA branch supply?

Answer 37

the thalamus

Question 38

What basal nuclei does the IC branch supply?

Answer 38

the globus pallidus and internal capsule

Question 39

What branches of blood supply go to the midbrain?

Answer 39

the PCA,SCA

Question 40

What branches of blood supply go to the pons?

Answer 40

the pontine artery, AICA, SCA

Question 41

What branches of blood supply go to the medulla?

Answer 41

the anterior spinal artery and posterior spinal artery

Question 42

What branches of blood supply go to the cerebellum?

Answer 42

the superior cerebellar arteries, anterior inferior cerebellar arteries, and posterior inferior cerebellar artery

Question 43

What are the two types of hemorrhagic stroke?

Answer 43

intraparenchymal and subarachnoid

Question 44

How can we differentiate intraparenchymal and subarachnoid strokes on a CT scan?

Answer 44

intraparenchymal will push brain structures to other spaces, subarachnoid will spread to all structures so it will be light all around

Question 45

What percentage of strokes are hemorrhagic?

Answer 45

13%

Question 46

What percentage of death cases come from hemorrhagic stroke?

Answer 46

40%

Question 47

What will happen if an individual under 55 yo has a hemorrhagic stroke?

Answer 47

drug abuse screening

Question 48

What are the type of ischemic stroke?

Answer 48

intraparenchymal only

Question 49

What percentage of strokes are ischemic?

Answer 49

87%

Question 50

What percentage of ischemic strokes are death cases?

Answer 50

60%

Question 51

What happens with an ischemic stroke?

Answer 51

hypoxic damage due to blood flow being blocked

Question 52

What is a hemorrhagic stroke?

Answer 52

when a blood vessel bursts within the brain

Question 53

What is a ischemic stroke?

Answer 53

when a blood clot blocks the blood flow in an artery within the brain

Question 54

What happens with stroke lesions?

Answer 54

localized damage

Question 55

What is diaschisis?

Answer 55

distant and systemic injury

Question 56

Which kind of stroke is worse?

Answer 56

hemorrhagic stroke is worse than ischemic

Question 57

What will trauma or aneurysm present like on a CT scan?

Answer 57

Star like presentation

Question 58

What is lateralization with a cerebral cortex stroke?

Answer 58

somatotopy/homunculus affected

Question 59

What happens with a sensory somatotopy with cerebral cortex stroke?

Answer 59

paresthesia/numbness

Question 60

What happens with a motor somatotopy cerebral cortex stroke?

Answer 60

paresis/paralysis

Question 61

What is a lacunar stroke?

Answer 61

small blood vessel, silent stroke

Question 62

What happens with a lacunar stroke?

Answer 62

compromised contralateral body hemisphere - NO sensory and motor decussations in the forebrain

Question 63

Does a lacunar stroke or a cortical stroke result in more functional loss?

Answer 63

lacunar more functional loss compared to the cortical stroke

Question 64

What happens with a brainstem stroke?

Answer 64

more functional loss - alert, arousal, and consciousness - vital centers Alternating hemiplegia - ipsilateral face/head - contralateral body

Question 65

Which arteries supply blood to the forebrain basal nuclei and diencephalon?

Answer 65

IC branches: internal capsule, globus pallidus ACA branches: nucleus accumbens, caudate MCA branches: caudate and putamen PCA branches: thalamus

Question 66

Suppose an ischemic stroke happens around the left rostral medulla. Which body parts and functions will be compromised?

Answer 66

Paresis/paresthesia of the L face and R hemiparesis