52. Blood Supply to Brain

Question 1

What are the paths for anterior and posterior circulation of the brain?

Answer 1

Anterior: CC - ICA - into cavernous sinus (Opthalmic a. branch) - PCA branch - Ant choroidal a. branch - terminates into ACA and MCA (final)

Posterior: Vertebral A (2) - (PICA branch) - Basilar A (1) - (AICA branch) - (Superior Cerebellar Artery) - termination: PCA (2) (branches of PCommA)

Question 2

What vessels compose the circle of willis?

Answer 2

PCA (2) + PCommA (2) + ACA (2) + ACommA (1)

Normal variants: missing part of circle - higher risk of ischemia if occluded

Question 3

What parts of the brain do the MCA, ACA, and PCA supply?

Answer 3

ACA: medial frontal brain
MCA: lateral frontal brain, in Sylvian Fissure (M1 segment sends perforator arteries to internal capsule on BG)
PCA: posterior brain and deep BG

Question 4

What is important about the perforator/lenticulostriate arteries? Where do they branch from?

Answer 4

Lacunar arteries from MCA M1 - tiny vessels directly off of large arteries - common site of rupture, hemorrage, occlusion, infarction (LACUNAR STROKE)

Question 5

Describe paths of venous anatomy

Answer 5

Cortical/bridging veins - SSS - confluence of sinuses - transverse sinus - sigmoid sinus - Int Jug Vein

Inf sag sinus - straight sinus - confluence of sinuses

Great Cerebral Vein - Basal vein of Rosenthal - straight sinus

Question 6

Sx of ACA infarction

Answer 6

• contralateral weakness and numbness leg (medial sensory/motor cortices)
• dyspraxia - cannot execute a task
• urinary incontinence

Question 7

Sx of MCA infarction

Answer 7

Dominant Hemisphere

• contralateral weakness/numbness in face/arm (lateral sensory/motor)
• contralateral hemianopsia (lose optic radiations)
• aphasia (loss of language centers)

Non-dominant Hemispheres
No aphasia, but +Attention deficits/neglect

Question 8

Sx of PCA infarction

Answer 8

• Contralateral Visual Field Loss

- Color Distortion/Visual Spatial Problems

Question 9

Vertebrobasilar Syndrome
(what it is, hallmark, deficits)

Answer 9

damage to brainstem, cerebellum, visual cortex
Hallmark: ALTERNATING SYNDROME: ipsilateral CN deficits, contralateral motor weakness
Sx: dizziness/vertigo, diplopia, dysphagia, ataxia, CN palsy, bilateral limb weakness (CS tract)

Question 10

Sx of Basilar Artery Occlusion

Answer 10

lose perforators to brainstem/pons
Severe quadriplegia (CS tract)
Coma "Locked in syndrome" - complete muscle paralysis except upward gaze

Question 11

Sx of borderline zone infarcts

Answer 11

lose watershed areas - due to hypotension

“Man in a barrel” - proximal arm weakness, tetraparesis

Question 12

Sx of Venous Thrombosis

Answer 12

High ICP: HA, papilledema, lethargy

Seizures