Blood Supply of Cortex-Wilson

Question 1

Blood supply to the medial brainstem

Answer 1

medial midbrain

medial medullary

Question 2

Blood supply to the lateral brainstem

Answer 2

lateral midbrain

lateral medulla

Question 3

What are the 3 arteries that supply the dorsolateral pons?

Answer 3

Caudal: AICA (pontomedullary junction)

Middle: circumferential (Short and long branches coming off of the basilar artery)

Rostral: Superior cerebellar

Question 4

What does superior cerebellar artery supply?

Answer 4

structures as the junction between the pons and midbrain

Question 5

What does AICA supply?

Answer 5

pontomedullary junction

Question 6

What syndrome is the circumferential long and short arteries associated with?

Answer 6

long branches produce the lateral pontine syndrome

Question 7

What tracts and nuclei are located at the dorsolateral part of the pons?

Answer 7

spinothalamic tract: descending hypothalamic fibers that provide control to the preganglionic sympathetic fibers in the spinal cord

spinal trigeminal tract: pain temperature coming from the face; extends all the way from spinal cord to the middle part of the pons

vestibular nuclei

motor nucleus of V

chief sensory of V

facial nucleus

Question 8

What will occur if you damage the spinothalamic tract in the dorsolateral pons?

Answer 8

you will not only effects of the spinothalamic get Horner’s syndrome ipsilaterally

Question 9

Lesions of what nucleus in the dorsolateral pons will result in paralysis of muscles of mastication?

Answer 9

motor nucleus of V

Question 10

Lesion of the facial nucleus/nerve fiber in the dorsolateral pons will result in what symptoms?

Answer 10

flaccid paralysis of facial muscles in the upper and lower part of the face

Question 11

What is the territory of long circumferential arteries?

Answer 11

• trigeminal spinal nucleus
• CN VII
• CN VI

Question 12

Lateral pontine syndrome involves what cranial nerves/nuclei and tracts?

The motor nerves are very important to recognize their symptoms because they tell you where the stroke is.

Answer 12

• motor nucleus of CN V
• sensory nucleus of CN V (chief, spinal, proprioceptive)
• nucleus and fibers of CN VII
• vestibular nucleus (AICA)
• auditory nucleus (AICA)
• spinothalamic tract
• descending hypothalamic
• spinal trigeminal tract (and nucleus)

Question 13

A lesion to the motor nucleus of V will lead to what symptoms?

Answer 13

You will get the motor nucleus of V leading to problems with muscles of mastication on one side; if you protrude the jaw, the jaw will deviate towards the lesioned side

Question 14

A lesion to the sensory nucleus of V will lead to what symptoms?

Answer 14

chief sensory nucleus of V: fine touch, vibration

spinal trigeminal nucleus: is more caudal and extends from the cervical to the middle of the pons; lesion will result in ipsilateral loss of pain and temperature on the face

proprioceptive nucleus of V (mesencephalic nucleus of V): strange nucleus in that the cells are unipolar neurons; unsure of symptoms if lesioned

Question 15

A lesion to the nucleus and fibers of CN VII will lead to what symptoms?

Answer 15

flaccid paralysis of muscles of facial expression whether there’s lesion in the nerves or nucleus

Question 16

A lesion to the fibers of CN VIII will lead to what symptoms?

Answer 16

near the pontine medullary junction you have fibers of CN VIII; also the vestibular nuclei and auditory nuclei

when you have the monaural loss of hearing especially a major decrease to the sensitivity of hearing then you’re probably involving the cochlear nuclei????

although not a motor nucleus the involvement of the auditory pathways tells you that you’re at the pontomedullary junction and the artery obstructed is AICA

ipsilateral decrease in sensation (pain and temp) of the face

Question 17

Where does the posterior cerebral artery go to?

Answer 17

occipital cortex particularly P2 where if lesioned there is loss of vision but with foveal sparing

Question 18

What is an important landmark for the posterior cerebral arteries?

Answer 18

posterior communicating arteries that goes in between internal carotid and posterior cerebral arteries

Question 19

What does P1 of posterior cerebral artery supply? What happens if it is lesioned?

Answer 19

supplies the midbrain and if it is unilateral you can get Weber’s syndrome getting the corticospinal tract and hemiataxia from the deep cerebellar fibers being affected (stroke involving the superior cerebellar peduncle or stroke involving the territory if the red nucleus)

the posterior comm is intact and you can still have blood coming from the internal carotid to the visual areas

Question 20

What occurs with a lesion to P2 of posterior cerebral artery?

Answer 20

a decrease of blood flow to the visual cortex and a loss of vision

Question 21

What occurs with a medial lesion of fibers coming off of basilar or P1 posterior cerebral artery?

Answer 21

you are hitting the corticospinal tract and red nucleus getting Weber’s syndrome

but you are sparing the medial lemniscus and spinothalamic tract

Question 22

Where does the labyrinthine artery travel and what does it supply?

Answer 22

labyrinthine artery traverses the internal auditory meatus and supplies the inner ear in the petrous portion of the temporal bone

it may come off the basilar artery (it has a lot of variations)

Question 23

The cerebral cortex is supplied by what 3 arteries?

Answer 23

1. posterior cerebral artery: going more towards the occipital cortex (visual cortex= calcarine fissure) and also ventral surface of the temporal lobe
2. internal carotid artery: gives off an anterior branch called anterior cerebral which supplies the frontal cortex running along corpus callosum
3. middle cerebral: a continuation of ICA going to the lateral part of the brain (cerebral cortex) giving off some ventral and dorsal branches

Question 24

If you have a thrombus that breaks free following a heart attack or if you’re palpating the internal carotid artery and the thrombus breaks free, this thrombus will do what?

Answer 24

go up and cause stroke of the either the entire middle cerebral artery or some of its branches

Question 25

Where does anterior cerebral artery run and what does it supply?

Answer 25

runs along the corpus callosum to the medial aspect of the frontal lobes and parietal lobe

Question 26

What are the two arteries that supply the medial aspect of the cerebral cortex?

Answer 26

posterior cerebral artery and anterior cerebral artery

Question 27

What is located in between the central sulcus and the parieto-occipital sulcus?

Answer 27

parietal lobe!!

Question 28

What is the major symptoms noted for the obstruction of the posterior cerebral artery?

Answer 28

-loss of vision with foveal sparing

the posterior cerebral artery runs to occipital cortex in the area of the visual cortex

Question 29

What occurs with obstruction or stroke of the anterior cerebral artery?

Answer 29

runs to prefrontal cortex so executive functions are affected

runs to region that gives rise to the corticospinal tract going to the lower limb –> monoplegia of lower limb; some involvement of the proximal part of the upper limb; symptoms would be contralateral to the stroke

supply the motor areas providing upper motor neuron innervation to lower limb

Question 30

Which arteries do cardiac embolism primarily form in the brain?

Answer 30

middle cerebral artery which is very unfortunate because they supply the important areas in terms of movement, speech, sensation, etc.

it is embedded in the lateral fissure

Question 31

Middle cerebral artery as it goes over the lateral fissure gives off what penetrating branches that supply the area of the basal ganglia?

Answer 31

lenticulostriate arteries

Question 32

Individuals with hypertension will have characteristic in their lenticulostriate arteries?

Answer 32

-the lenticulostriate arteries are small and have tendency to form aneurysm

-if there is rupture of these aneurysms you get focal lesions called
lacunar infarcts

Question 33

How do lacunar infarcts result?

Answer 33

individual with HTN and because of the high blood pressure overtime this can cause weakening in the walls of the artery and the arteries start to balloon out and tilt until they actually rupture

the rupture produces a focal infarct where it ruptures called a lacunar infarct

Question 34

Which Brodmann’s area will be affected by middle cerebral artery infarct?

Answer 34

area 4 and 6

primary and secondary motor and somatosensory cortex

On the left side of brain:

• Wernicke’s area: sensory aphasia
• broca’s aphasia: motor aphasia

Question 35

What is the angular cortex? What syndrome and symptoms results if there is a stroke in this area?

Answer 35

follow the lateral fissure up on the LEFT side in most people

Gerstmann’s syndrome

• finger recognition difficulty
• alexia
• calculation difficulty

Question 36

Stroke in the parietal cortex will result in?

Answer 36

• loss of spatial perception

- person will not recognize half of their world

Question 37

What artery supplies your frontal eye fields (area 8)?

Answer 37

middle cerebral artery

Question 38

What occurs with lesions to the frontal eye field?

Answer 38

the ability to look to the opposite side voluntarily is lost because the other cortex is dominating and the eyes is deviated towards the right way (where the stroke is located); eyes are looking in the opposite direction to where you have hemiplegia or monoplegia

Question 39

In order to control eye movments

Answer 39

fibers descend and cross to the contralateral pons to the paramedian pontine reticular formation for horizontal gaze next to the abducens nucleus

Question 40

What occurs with a lesion in the pons involving the paramedian pontine reticular formation?

Answer 40

the frontal eye field is intact but you still get a contralateral hemiparesis because you’re next to the corticospinal tract

but the paramedian pontine reticular formation on this side is receiving cortical input from the frontal eye field

eyes will deviate towards where the paralysis is (wrong way eyes)

Question 41

Describe the circuit for voluntary horizontal parallel eye movement.

Answer 41

note the contralateral cortical control of the frontal eye fields ?????

Question 42

embolism in middle cerebral artery

Answer 42

area of watershed will be spared because of collateral branches from anterior and posterior cerebral arteries ?????

extent of infarct is smaller than the area of the territory of the middle cerebral artery

watershed areas are often spared following obstruction of a single cerebral artery

Question 43

?????Perfusion through these major arteries are less maybe due to low blood pressure, stroke, or heart attack plummeting your BP. What type of infarct does this cause?

Answer 43

infarcts in areas of overlap called the watershed infarct

watershed infarct may occur with severe drops in systemic blood pressure from shock or cardiac insufficiency

Question 44

The ACA territory and ACA-MCA watershed???

Answer 44

lower limb and proximal part of the upper limb

Question 45

Blood brain barrier

Answer 45

very important concept especially in pharmacy as drug administered to patient often times do not cross this barrier while some do

To cross the BBB, substances must be actively transported across the endothelial cells.

The BBB protects the brain from chemical fluctuations of blood that would disrupt synaptic transmission.

Trauma to the brain may disrupt the BBB resulting in vasogenic (excessive extracellular fluid) edema and cytotoxic edema (excessive intracellular fluid)