47 Blood supply and CSF circulation Flashcards
Which artery supplies anterior 2/3 of the brain, including major parts f the cerebral hemisphere and the basal ganglia and internal capsule?
Internal carotid artery
Which artery supplies posterior 1/3 of the CNS, including the cerebellum and brainstem?
Vertebral artery (> Basilar artery)
State the main branches of the vertebral and basilar artery.
- Anterior spinal artery
- Superior cerebellar artery
- Anterior inferior cerebellar artery
- Posterior inferior cerebellar artery
- Posterior cerebral artery
Anterior spinal artery supplies?
Medulla and spinal cord
Oculomotor nerve is in between which 2 arteries?
Posterior cerebral artery and
Superior cerebellar artery
(both from basilar artery)
In middle medullary syndrome, what structures are affected? Why?
Motor nuclei of the cranial nerves, hypoglossal nucleus contribute to the hypoglossal nerve;
pyramid > UMNL
- anterior spinal artery lesion
In lateral medullary syndrome, what structures are affected? Why
Sensory nuclei, deficits in pain (spinothalamic tract, spinotrigeminal nuclei…)
- posterior inferior cerebellar artery, vertebral artery lesion
______________, branch of ICA goes to the temporal lobe and supplies the inferior horn of the ventricle by choroid plexus and also the hippocampus.
Anterior choroidal artery
also posterior limb of internal capsule
The anterior cerebral arteries on 2 sides are joint by the ____________ artery.
anterior communicating
The posterior communicating artery links which 2 arteries?
ICA and posterior cerebral artery
Ophthalmic artery is a branch of?
ICA
List spots where aneuryms are commonly associated in the Circle of Willis.
- Anterior communicating artery
- ICA
- Posterior cerebral artery (between 2)
What will happen when there is aneurysm in the posterior communicating artery?
Deficits in CN3, as CN3 is in between posterior cerebral artery and superior cerebellar artery
When aneurysm bursts, it may lead to?
subarachnoid bleeding
Which 2 types of branches are present in cerebral arteries? What types of structures they supply?
- Cortical branches
2. Central (penetrating) branches: supplying deeper structures like the basal ganglia and internal capsule
The ______________ artery emerges from the lateral sulcus on the surface of the insula.
Middle cerebral
Cortical branches of middle cerebral artery supplies?
What are the significant structures involved?
- Lateral surface of the cerebral hemisphere
- Broca’s area
- Wernicke’s area
- Angular gyrus, supra marginal gyrus
- Primary auditory cortex
Cortical branches of Posterior cerebral artery supplies?
Inferior and medial surfaces of temporal and occipital lobes, (extends little over lateral surface of hemisphere)
Lesion of cortical branches of the middle cerebral artery?
- Broca’s area: expressive aphasia
- Wernicke’s area: Receptive aphasia
- Angular gyrus: cannot comprehend abstract figures
- Parietal cortex: hemineglect
Important structures supplied by the cortical branches of the posterior cerebral artery?
What will happen if there is a lesion?
- Fusiform gyrus - unable to recognise faces
- Hippocampus - unable to recognize places, memory formation
- Primary visual cortex
Cortical branches of Anterior cerebral artery supplies?
- Medial surface of the frontal and parietal lobes
- Extends over to margin of lateral surface
Important structures supplied by the cortical branches of the anterior cerebral artery? Lesion will lead to?
- Corpus callosum (unable to communicate between 2
hemispheres, unable to carry out verbal commands) - Cingulate gyrus
What are the central branches of the anterior cerebral artery?
Medial striae
What does the medial striae arteries supply? What will happen if there is a lesion?
from ACA, supplies
- the head of caudate nucleus 2. putamen
- anterior limb of the internal capsule
Lesion: Hyperkinesia
What are the central branches of the posterior cerebral artery? Important structures supplied by them?
Thalamoperforating branches
- thalamus
- hypothalamus
- lateral ventricle
- third ventricle
- midbrain (weber’s syndrome)
Lateral striae arteries are central penetrating branches of the _____________. They mainly supply?
Middle cerebral artery;
- caudate, putamen, globus pallidus
- internal capsule (anterior and posterior limbs)
What will happen if there is a lesion in lateral strain arteries?
- Hyperkinesia - basal ganglia
2. UMNL (motor deficits) - anterior and posterior limbs of IC
Anterior choroidal artery is the central perforating branch of ICA. What structures does it supply?
- Choroid plexus of the lateral ventricle
- Hippocampus
- Globus pallidus
- Posterior limb of internal capsule
- it goes backward to the medial aspect of the temporal lobe
Why capsular stroke will cause severe motor and sensory deficits?
Capsular stroke - due to the blockage of the lateral striae arteries that supplies the anterior and posterior limbs of the internal capsule
Genu: corticonuclear fibers
Posterior limb: corticospinal and corticoreticular fibers
How does cerebral veins drain to IJV?
Cerebral veins > Dural sinuses > IJV
Which of the following about cerebral veins is true?
A. Cerebral veins have no valves
B. Superior ones drain the cortex and subcortical white matter
C. Superior ones mostly drain to inferior sagittal sinus
D. They have a lot of anastomoses
E. Can be divided into superficial and deep veins
All except C;
should be to superior sagittal sinus
What structures do the deep cerebral veins drain from?
Diencephalon, deep white matter, basal ganglia, choroid plexus
Where do the deep cerebral veins end?
in the internal cerebral veins, great cerebral vein of Galen > straight sinus
State the venous drainage system.
Internal cerebral veins > Great cerebral vein of Galen
+ Inferior sagittal sinus
> Straight sinus + superior sagittal sinus
> Confluence of sinus
> Transverse sinus
> Sigmoid sinus
> IJV
The ventricular system is lined with __________ and it communicates with the _________ space.
ependyma;
subarachnoid space
CSF is secreted by ________________ which are surrounded by specialised ependyma, the choroidal epithelium to control the composition of CSF.
Choroid plexus / choroidal epithelium
CSF is produced in the ___________ and will enter the _____________.
Ventricular system; subarachnoid space
Compared to blood, CSF is: A. lower in glucose B. lower in proteins C. lower in red blood cells D. lower in leukocytes
All of the above
C: except in subarachnoid bleeding
Diseases of the CNS will cause what changes to the CNS?
Rise in CSF, especially WBC in CSF
State the sites where the ventricular system is prone to hydrocephalus.
Narrow sites
- Anterior margin of the thalamus: inter ventricular foramen (pineal tumour) (between lateral ventricle and 3rd ventricle)
- Cerebral aqueduct (between 3rd and 4th ventricle)
(also apertures)
Which part of the ventricular system is highly related to the midbrain?
cerebral aqueduct
4th ventricles contains 2 lateral and 1 median apertures for?
communicating with the subarachnoid space
Roof and Floor of 4th ventricle is?
Roof: cerebellum;
Floor: pons and medulla
3rd ventricle is bounded by?
Diencephalon
Lateral ventricles consists of what parts?
Anterior, posterior, inferior horns, body, atrium
Where is the median aperture located?
Roof of the 4th ventricle
What does it meant by closeand open medulla?
close = leave by central canal open = leave by median aperture of 4th ventricle
Caudate nucleus is medial/lateral to the lateral ventricle?
Lateral
State the flow of CSF circulation from the lateral ventricle to the veins.
Lateral ventricle > inter ventricular foramen > 3rd ventricle > cerebral aqueduct > 4th ventricle > lateral and median apertures > subarachnoid spaces > arachnoid granulations < superior sagittal sinus
What is the subarachnoid space?
Space between the arachnoid and the pia, containing CSF, arteries and veins, arachnoid trabecular
______________ is an expanded subarachnoid space.
Examples are?
Arachnoid cistern;
- cerebellomedullary (cisterna magna)
- pontine
- superior
- interpeduncular
- Chiasmatic cisterns
What is the function of arachnoid cap cells?
Any clinical significance?
Act as a valve for unidirectional movement of CSF;
Cellular origin of a benign tumour, meningioma
Reasons for excessive CSF accumulation?
- Increased production
- Interference with circulation
- Interference with absorption
How can a doctor examine a patient with CSF accumulation?
Hydrocephalus: accumulation of CSF either in the ventricular system/ subarachnoid space causes an increase in CSF pressure, causes dilation of ventricles, head enlargement in infants and papilledema.
Examine the optic disk of the eye where the optic nerve and disk is covered by meninges. Will be swollen if CSF accumulation.
What is non-communicating hydrocephalus? What will happen?
The communication between the ventricular system and the subarachnoid space is blocked = obstructive hydrocephalus.
Which parts of the ventricular system will be affected in Obstructive hydrocephalus due to compression of cerebral aqueduct?
Compression in cerebral aqueduct > upstream of cerebral aqueduct: 3rd ventricle + lateral ventricle > dilatation there, but not in downstream (4th ventricle etc.)
What are the 3 different bleedings associated with meninges? Rupture of what blood vessels?
- Epidural: from middle meningeal artery
- Subdural: from torn cerebral vein and its junction with dural sinus
- Subarachnoid: from ruptured aneurysm of artery in subarachnoid space
