7 - Blood Supply of CNS

Question 1

Internal Carotid origin

Answer 1

Common Carotid

Question 2

Vertebro-Basilar origin

Answer 2

Subclavian arteries

Question 3

SC blood supply

Answer 3

Segmental

Question 4

Brain blood supply

Answer 4

Regional

Question 5

Percent occlusion of arteries before blood flow is affected

Answer 5

75%

Question 6

Site where Carotid-VB unite

Answer 6

PCOM

Question 7

Each ICA supplies how much brain blood flow?

Answer 7

40% each; 80% total

Question 8

Vertebral artery supplied how much brain blood flow?

Answer 8

20%

Question 9

PCA supplies…

Answer 9

• supplies midbrain, thalamus, posterior parts of cerebral cortex
• AND CALCARINE, so visual cortex!
• ends in temporal, occipital lobes

Question 10

PICA

Answer 10

• Supplies inferior cerebellym, dorsolateral medulla
• May give rise to a posterior spinal artery

Question 11

AICA

Answer 11

• Blood supply to inferior carebellum
• Arises at pontomedullary junction

Question 12

SCA

Answer 12

• Blood supply to superior cerebellum and lateral aspect of brainstem

Question 13

SC Watershed Zone

Answer 13

• Between C8 and T9, because few spinal medullary arteries (from radicular arteries from segmental arteries providing supporting blood supply to SC)
• T9/T10 and below is supplied by Great radicular artery (of Adamkiewicz)

Question 14

Great radicular artery (of Adamkiewicz)

Answer 14

• Spinal medullary artery that supplied T9 and below
• End of watershed zone of SC (C8-T9)

Question 15

Vertebral arteries supply…

Answer 15

…medulla and everything below it

Question 16

Basilar artery supplies…

Answer 16

Pons

Question 17

MCA supplies…

Answer 17

• Most of lateral frontal, parietal, and temporal lobes
• Sensory and motor areas associated with face & upper extremity
  *

Question 18

MCA Structure

Answer 18

• M1: horizontal segment
  
  • Gives off lenticulostriate arteries for basal ganglia
• M2: Sylvian segments
  
  • Branches into two: superior, inferior
• M3: Cortical segments (pie-shaped sections)

Question 19

Anterior communicating artery

Answer 19

Connects both arterial cerebral arteries

Question 20

Posterior communicating artery

Answer 20

Connects internal carotid with branches of PCA

(site of unity btwn internal carotid and VB systems)

Question 21

ACA supplies…

Answer 21

• Medial and superior frontal (crowns) and medial, superior parietal lobes
• Sensory and motor areas associated with trunk and lower extremities

Question 22

Anterior choroidal artery arises…

Answer 22

From internal carotid, right before change to middle cerebral artery

Question 23

ACh.A supplies…

Answer 23

• Choroid plexus of lateral ventricles
• Optic tract
• Small part of thalamus
• Small part of basal ganglia
• Hippocampus (with PCA)
• Amygdala
• Posterior limb of internal capsule
  
  • Most important structure irrigated by AChA!
  • Large white matter bundle carrying fibers to/from cerebral cortex, including primary motor and primary somatosensory cortices.
  • Infarction of the AChA produces motor deficits because of damage here
  • Can also cause visual deficits as AChA also runs with and supplies the optic tract and visual parts of the thalamus

Question 24

Left-sides embolic strokes

Answer 24

• Clots can form in the left auricle (of heart), particularly during atrial fibrillation
• Emboli more commonly ascend the left common carotid artery
• This vessel is almost perfectly aligned with the vertical segment of the aorta
• Left-side strokes are thus more common than right-side strokes

Question 25

Brachial Diplegia

Answer 25

• Man in a barrel syndrome
• Shoulder, upper trunk areas of motor cortex are vulnerable to MCA/ACA watershed stroke
• Results in inability ot mabduct arms and flex elbows