Blood supply of the CNS Flashcards
Brain recieves this amount of cardiac output
15%
Amount of oxygen consumed by brain daily
25%
Brain cannot withstand
Lack of oxygen/anoxia
How many arteries supply the brain
- Broken down into 2 pairs
Vessels of the brain lie in this region
Subarachnoid space
What arteries supply the brain
A pair of internal carotid arteries
A pair of vertebral arteries
Pair of vertebral arteries fuse to form the
Basilar arteries
The internal carotid arteries supplies this part of the brain
Forebrain, except the occipital lobe
The vertebral arteries supply this part of the brain
The occipital lobe
Brainstem
Cerebellum
Spinal cord
Spinal cord receives from these areteries
Vertebral arteries
Spinal segmental arteries
Where does internal carotid originate from
Bifurcation of common carotid artery
Course of internal carotid artery
Passes through neck - cervical part
enters cranium via carotid canal- petrous part
enters carvenous sinus - carvenous part
Becomes cerebral part where it divides into 5 terminal branches
Branches of internal carotid
Ophthalmic artery Posterior communicating artery Anterior choroidal artery Anterior cerebral artery Anterior communicating artery Middle cerebral artery
Where does vertebral artery arise from
Subclavian artery
Course of vertebral artery
Arises from subclavian
Passes through vertebral foramina
Enters the cranium via foramen magnum
Joins contralateral vertebral artery to form basilar artery
Branches of vertebral artery
Anterior spinal artery
Posterior spinal artery
Posterior inferior cerebellar artery
Basilar artery
At which point does basilar artery bifurcate
Midbrain
Basilar artery proceeds in this direction
Rostrally
Basilar artery bifurcates into
2 posterior cerebellar areries
Internal carotid and its branches form
Anterior circulation
Basilar artery and its branches form
Posterior circulation
Branches of basilar artery
Labyrinthine posterior cerebral artery Anterior inferior cerebellar artery Superior cerebellar artery Pontine arteries
Where is basilar artery found
Ventral surface of the pons, in the basilar groove.
What is the circle of willis
Arterial anastomosis between internal carotid artery and vertebrobasilar systems
Location of the circle of willis
interpeduncular fossa at base of the brain
Branches of circle of willis
Anterior cerebral artery
Middle cerebral artery
Blood flow around circle of willis
Little to no blood flow
Importance of circle of willis
Acts to provide collateral blood flow /anastomotic flow between anterior and posterior circulations of the brain protecting it against ischemic damage in an event of vessel damage in one or more areas
Danger of circle of willis
Common area of arterial malformations/ aneurysms
Occlusion in the cortical branch of middle cerebral artery causes
Major motor and somatosensory deficits
Occlusion of anterior cerebral artery
Affects the paracentral lobule i.e leg and perineum
Occlusion in posterior cerebral artery affects
primary visual cortex
Corpus striatum and internal capsule supplied by
Medial and lateral striate of MCA
Recurrent branch of ACA
Anterior choroidal
Thallamus supplied by
central branches of PCA
Posterior communicating artery
Optic chiasma supplied by
ACA
Optic tract supplied by
Anterior choroidal artery
posterior cerebral artery
Optic radiation supplied by
MCA
PCA
Cerebellum supplied by
PICA
AICA
SCA
Pons supplied by
AICA
SCA
Basilar
Pontine
Midbrain supplied by
PCA SCA Basilar Posterior communicating Anterior choroidal
Medulla supplied by
PICA
vertebral
anterior spinal
posterior spinal
Venous drainage of brain
System of cerebral veins—.>dural venous sinuses….>Internal jugular vein
Emissary veins connect
extracranial veins with dural sinuses
The basilar venous plexus location
base of brain
Basilar venous plexus communicates with
epidural venous plexus of spinal cord
2 types of cerebral veins are
Superficial
Deep
Superficial veins
Lie on the surface of cerebral hemispheres
Superficial veins drain into
superior sagittal sinus
Deep veins
Drain internal structures into the straight sinus
Longitudinal vessels that supply spinal cord
single anterior spinal artery
pair of posterior spinal artery
Segmental arteries that supply spinal cord
spinal branches of vertebral, deep cervical, intercostal, lumbar arteries
Anterior spinal cord location
Anterior median fissure
Posterior spinal artery location
posterolateral sulcus
Where does anterior spinal artery supply
upper cervical levels with supplement from vertebral arteries
Anterior spinal artery supplies
Anterior 2/3rd of spinal cord
Base of posterior horn
Variable portion of lateral corticospinal tract
Posterior spinal arteries are
plexiform network of small arteries
Function of posterior spinal arteries
supply posterior columns, substantia gelatinosa, dorsal root entry zone, a portion of lateral corticospinal tract
Below the lower cervical segments spinal cord depends on this for survival
radicular arteries
The great radicular artery present at which level
T9-L2
Main supply to lower 2/3rds of the cord
Great radicular
Spinal cord does not rely solely on longitudinal arteries because they are
end arteries. Input of segmental arteries esp artery of Adamkiewicz
Venous drainage occurs along
6 places
Anterior and posterior midlines
line of attachment of dorsal and ventral roots on each side
Veins in spinal cord are drained by
Radicular veins which empty into epidural venous plexus
