CNS Blood Supply

Question 1

vessels involved in the circle of willis

Answer 1

-ICA
-ACA
-Acom
-Pcom
-PCA
-basilar artery

Question 2

carotid syphon

Answer 2

tortuous portion of the ICA with high risk for calcification and aneurysm

Question 3

terminal branches of the internal carotid artery (ICA)

Answer 3

1) anterior cerebral arteries (ACA)
2) middle cerebral arteries (MCA)

Question 4

intermediate branches of the internal carotid artery (ICA)

Answer 4

1) ophthalmic artery
2) posterior communicating artery (Pcom)
3) anterior choroidal artery

Question 5

ACA branches & their perfusion

Answer 5

1) superficial branches to:
-paracentral lobule, where hip, lower limb, and genital area are represented
-frontal lobe cognitive area
-cingulate gyrus and corpus callosum

2) perforating branches to:
-deep cerebral nuclei
-internal capsule

Question 6

A1-A4 of the anterior cerebral artery (ACA)

Answer 6

*A1 is pre-communicating (before the anterior communicating artery)
*A2, A3, and A4 are post-communicating

Question 7

signs of an ACA stroke

Answer 7

contralateral paralysis and sensory loss - lower limb, urinary incontinence:
*weakness of contralateral LEG
*sensory loss of contralateral LEG
*urinary incontinence
*altered mental status or judgement
*behavioral and emotional disorders

Question 8

A1 vs A2 occlusion of ACA

Answer 8

*in A1 occlusion, there is distal ACA circulation via Acom
*in A2 occlusion, there is NO distal perfusion of tissue

Question 9

segments of the MCA

Answer 9

1) M1 = deep/horizontal
2) M2 = lateral (sylvian) fissure
3) M3/M4 = cortical (superior and inferior divisions)

Question 10

MCA perfusion and branches

Answer 10

1) superficial branches to:
-lateral surfaces of frontal, parietal, and temporal lobes
-cortex in sylvian sulcus, including insula
-portion of occipital lobe

2) deep perforating branches

Question 11

important functional areas supplied by the MCA

Answer 11

*primary and secondary motor
*primary and secondary somatosensory
*parietal association cortex
*Wernicke’s area and Broca’s area
*primary and secondary auditory

Question 12

signs of an MCA stroke

Answer 12

contralateral paralysis and sensory loss - lower face & upper limb; aphasia (if dominant hemisphere) OR hemineglect (if nondominant hemisphere):
*contralateral weakness of UPPER LIMB AND FACE
*expressive (non-fluent) aphasia (Broca’s)
*contralateral sensory loss of UPPER LIMB AND FACE
*receptive (fluent) aphasia (Wernicke’s)
*gaze preference to ipsilateral side
*neglect: non-dominant hemisphere
*possible partial visual deficits due to white matter involvement

Question 13

lenticulostriate arteries

Answer 13

*arteries that supply regions of the BASAL NUCLEI
*lesions found in striatum / internal capsule

Question 14

medial lenticulostriate arteries supply?

Answer 14

supply the globus pallidus, the medial portion of the putamen, and the anterior internal capsule

Question 15

medial lenticulostriate artery - alternative name

Answer 15

Recurrent Artery of Heubner

Question 16

medial lenticulostriate arteries arise from?

Answer 16

arise from the A1 segment of the ACA (anterior cerebral artery)

Question 17

lateral lenticulostriate arteries arise from?

Answer 17

arise from the proximal MCA (usually M1)

Question 18

lateral lenticulostriate arteries supply?

Answer 18

supply the lateral portion of the putamen and the posterior internal capsule

Question 19

stroke in the lenticulostriate arteries would present with what signs?

Answer 19

contralateral paralysis
*ABSENCE of cortical signs (such as neglect, aphasia, or visual field loss)

Question 20

the posterior communicating artery supplies blood to?

Answer 20

supplies blood to thalamus, optic chiasm, and regions of the hypothalamus

Question 21

what cranial nerve does the posterior communicating artery travel adjacent to?

Answer 21

Pcom travels adjacent to the oculomotor nerve (CN III)

Question 22

what is a classic Pcom stroke sign?

Answer 22

third nerve palsy (ptosis, down and out pupil, and mydriasis on the ipsilateral side)

Question 23

what do the vertebral arteries arise from

Answer 23

subclavian arteries

Question 24

what are the branches of the vertebral arteries

Answer 24

1) anterior spinal artery
2) PICA and AICA
3) basilar

Question 25

where do the 2 vertebral arteries join to form the basilar artery

Answer 25

at the **junction between the pons and medulla**

Question 26

what are the branches of the basilar artery

Answer 26

1) superior cerebellar arteries (SCA) 2) basilar divides into 2 posterior cerebral arteries (PCA)

Question 27

posterior cerebral artery (PCA) - perfusion and branches

Answer 27

***occipital cortex** visual areas *inferior temporal lobe *splenium of corpus callosum *hippocampus *portions of midbrain

Question 28

PCA divisions

Answer 28

*P1 is pre-communicating (before posterior communicating artery) *P2, P3, and P4 are post-communicating

Question 29

P1 vs. P2 occlusions

Answer 29

*with **P1 occlusions, there is distal PCA circulation via Pcom** *with P2 occlusions, there is NO distal perfusion of cortex

Question 30

clinical signs of a PCA stroke

Answer 30

***CONTRALATERAL homonymous hemianopsia:** loss of one half of the visual eye fields *in-utero strokes are most commonly strokes in the PCA (fetal PCAs)

Question 31

watershed zones

Answer 31

*regions of the brain that receive **dual blood supply branches of 2 major arteries** *2 important watershed zones in the brain: 1. ACA-MCA watershed 2. PCA-MCA watershed

Question 32

superior cerebellar artery (SCA) supplies?

Answer 32

cerebellar hemispheres and parts of the midbrain

Question 33

clinical signs of SCA stroke

Answer 33

**trigeminal neuralgia** (severe pain in the jaw) due to compression of the trigeminal nerve

Question 34

anterior inferior cerebellar artery (AICA) supplies?

Answer 34

ventral surface of cerebellum and the **lateral pons**

Question 35

clinical signs of AICA stroke

Answer 35

***loss of pain and temperature to FACE (ipsilateral) & LIMBS (contralateral)** *LOSS OF HEARING, VERTIGO, and NYSTAGMUS

Question 36

posterior inferior cerebellar artery (PICA) supplies?

Answer 36

**LATERAL MEDULLA**, as well as vermal region and inferior lateral surface of the cerebellar hemisphere

Question 37

clinical signs of PICA stroke

Answer 37

***dysphagia, hoarseness, tongue deviation, loss of gag reflex** *ipsilateral **Horner's syndrome** (ptosis, miosis, hemianhidrosis) *cerebellar ataxia *decreased pain and temperature from contralateral body, ipsilateral face

Question 38

lateral medullary (Wallenburg's) syndrome

Answer 38

PICA STROKE presents as: *dysphagia, hoarseness, tongue deviation, loss of gag reflex *ipsilateral Horner's syndrome

Question 39

midbrain blood supply

Answer 39

*PCA primarily (some from SCA)

Question 40

most common midbrain stroke syndrome

Answer 40

**Weber Syndrome:** -midbrain stroke due to occlusion of branches of PCA -causes **ipsilateral CN III palsy & contralateral hemiplegia**

Question 41

Weber Syndrome

Answer 41

*occlusion of PCA *ipsilateral oculomotor (CN III) palsy *contralateral weakness/hemiplegia of body and face

Question 42

pontine blood supply

Answer 42

*basilar artery (paramedian, short, and long branches) *SCA contributes to rostral pons

Question 43

example of a pontine syndrome

Answer 43

Locked In Syndrome

Question 44

Locked In Syndrome

Answer 44

*due to **complete occlusion of basilar artery** *pt can move their eyes but nothing else: -quadriplegia, loss of voluntary facial & mouth & tongue movements, loss of horizontal but not vertical eye movements

Question 45

medullary blood supply

Answer 45

MEDIAL = anterior spinal artery LATERAL = PICA

Question 46

syndrome associated with occlusion to MEDIAL medullary blood supply

Answer 46

Medial Medullary Syndrome of Dejerine: **1. contralateral paralysis (upper & lower limbs) 2. decreased contralateral proprioception 3. ipsilateral hypoglossal dysfunction (tongue deviates ipsilaterally)** *caused by **occlusion of anterior spinal artery**

Question 47

all blood is drained from the brain by what vein

Answer 47

INTERNAL JUGULAR vein

Question 48

bridging veins

Answer 48

*veins that drain underlying neural tissue, penetrate the dura mater, and empty into the dural sinuses note - subdural hematomas classically result from tearing of the bridging veins

Question 49

acute, subdural hematomas most commonly develop after rupture of ?

Answer 49

rupture of a bridging vein

Question 50

superior sagittal sinus

Answer 50

*largest venous sinus ***CSF return to venous drainage through** bridging veins (**arachnoid granulations**)

Question 51

issues associated with the superior sagittal sinus

Answer 51

1) occlusion = increased intracranial pressure (potentially fatal) 2) shearing = subdural hematoma 3) superior sagittal sinus thrombosis (SSST) = stroke related to hypercoagulability

Question 52

cavernous sinus

Answer 52

*venous sinus that drains the eyes and superficial cortex ***ICA and CNs III, IV, V1, V2, and VI pass through**

Question 53

cavernous sinus thrombosis

Answer 53

*thrombosis secondary to **bacterial infection in the face** *can cause headache, proptosis, and ipsilateral CN deficits