Blood Supply To The Ventricles

Question 1

CSF has lower _____ than plasma.

CSF contains ___ similar to plasma.

Answer 1

Glucose and protein

Na, Cl, Mg

Question 2

The ventricular system is lined by ____ and formed into vascular folds called _____, which produces the CSF. Where is this located?

Answer 2

Ependyma (glial cells)

Choroid plexus

Lateral ventricles, 4th ventricle

Question 3

Choroid plexus makes CSF and releases it into the ____.

Lateral ventricle connects to 3rd ventricle by ____.

3rd ventricle connects the the 4th ventricle by _____.

4th ventricle is connected to the subarachnoid space by ____.

CSF will either go through arachnoid granulation into the ____ or down the ____ in the SC.

Answer 3

Lateral ventricle

Interventricular foramina of Monroe

Cerebral aqueduct

Lateral aperture (Foramen of Luschka) and median aperture (Foramen of Magendie)

Superior sagittal sinus; central canal

Question 4

_____ is caused by an increase in cerebral mass/size due to excessive CSF.

Answer 4

Hydrocephalus

Question 5

External or communicating hydrocephalus is caused by what?

What are the two types?

Answer 5

Excessive accumulation of CSF in the subarachnoid space; compresses CSF; outside the ventricles, which are normal size

Supratentorial external hydrocephalus: above the tentorium cerebelli; senile atrophy of the cortex (Alzheimer’s)

Infratentorial external hydrocephalus: below the tentorium cerebelli

Question 6

What causes internal or noncommunicating hydrocephalus?

What obstructions can cause this?

Answer 6

Obstruction preventing the drainage of CSF produced in the ventricular system to the subarachnoid space

Causes dilation of the ventricles proximal to the obstruction

Interventricular foramen: 3rd ventricle choroid plexus ependymoma

Cerebral aqueduct: midbrain astrocytoma

Median and lateral aperatures: Arnold-chiari malformation of dandy-walker cyst

Question 7

_____ is a combination of infratentorial external hydrocephalus and internal hydrocephalus.

What causes it?

Answer 7

Communicating hydrocephalus

Obstruction of the narrow space between the tentorial notch and midbrain -> caused by adhesions or fibrosis in subarachnoid space -> caused by previous inflammation (infantile meningitis), cerebral edema, uncial herniation

Question 8

In communicating hydrocephalus, CSF can move through the ventricular system into the ____.

CSF cannot circulate over the cerebrum to be restored at the _____ near the superior sagittal sinus.

What does this cause?

Answer 8

Infratentorial subarachnoid space

Arachnoid villi

Hypertrophy of ventricles (internal hydrocephalus) and accumulation of CSF in the infratentorial space (external hydrocephalus)

Question 9

What are clinical signs of hydrocephalus in infants and young children (less than 2 y/o)?

Adults?

Answer 9

Increase intracranial pressure is compensated by enlargement of cranial sutures

Increased intracranial pressure but sutures are fused so prevents head enlargement

Papilledema: CSF fills the subarachnoid space around the optic N causing bulging of optic disc

Abducens palsy: medially deviated eye

Ventriculomegaly: mental retardation

Question 10

What veins drain the SC?

Where does it receive drainage from?

What does it empty into?

Where is it located?

Answer 10

Internal venous plexus of Batson

Receives drainage from veins in the SC

Empties into intervertebral veins -> segmental veins -> IVC

Located in the epidural space

*easy for cancer to metastasize

Question 11

Deep drainage of the cerebral hemispheres: internal cerebral V

What does it receive from?

What does it drain into?

Location?

Answer 11

Receives thalamostriate V (drains corpus striatum) and anterior septal veins (draining limbic lobe)

Drains into the great vein of Galen

Runs next to the parahippocampal gyrus

Question 12

Deep drainage of the cerebral hemispheres: basal V of rosenthal

What does it receive from?

What does it drain into?

Location?

Answer 12

Receives from middle deep cerebral (drains insula) and anterior cerebral V (drains frontal lobe)

Drains into great V of Galen

Runs next to the cerebral peduncle

Question 13

Deep drainage of the cerebral hemispheres: great V of Galen

What does it receive from?

What does it drain into?

Location?

What does an occlusion cause?

Answer 13

Receives from internal cerebral V and basal V of rosenthal

Drains into the straight sinus -> confluence of sinuses

Runs next to the posterior portion of the corpus callosum

Fatality: because drains the deep cerebrum
Great V varix may compress the pineal body and the posterior commissure

Question 14

The superior sagittal sinus usually empties directly into the ____.

Thrombosis causes what?

Straight sagittal sinus empties directly into the ____.

Thrombosis causes what?

Answer 14

R transverse sinus

Cortical ischemia and/or necrosis

L transverse sinus

Ischemia and/or necrosis of deep cerebrum; usually fatal

Question 15

What four structures make up the blood brain barrier?

What is the fx?

What 3 locations do not have the BBB?

Answer 15

Endothelial cell layer
Basement membrane
Pericytes
Foot processes of astrocytes and oligodendrocytes

Barriers to passage of large molecules to and from the CNS

Pineal body, area postrema, median eminence of the hypothalamus

Question 16

What two arteries pierce the dura mater?

Where do they run?

What arteries do they give off and where do these go/do?

Answer 16

Internal carotid A and vertebral A

Subarachnoid space

Cerebral A: supply blood to the brain; run in subarachnoid space -> branches penetrate the brain parenchyma while being surrounded by Virchow-Robin space (perivascular space) and pia mater

Question 17

What four branches off the internal carotid A supply the anterior cerebrum?

Answer 17

Ophthalmic A

Anterior choroidal A

Anterior cerebral A

Middle cerebral A

Question 18

What does the anterior choroidal A supply?

What is it prone to?

Answer 18

Choroid plexus of lateral ventricle, internal capsule, basal ganglia, thalamus, rostral midbrain

Thrombosis due to long course in subarachnoid space; can causes vascular insufficiency to globes pallidus and hippocampus in elderly

Question 19

What does the anterior cerebral A supply?

Location?

What does an occlusion cause?

Answer 19

Anterior 2/3 of the medial side and supero-lateral portion of the hemisphere, paracentral lobule region, sensation and motor to the LE

Runs next to olfactory and optic N

Lack of blood to the paracentral lobule region of the cortex -> contralateral paresis and/or paraesthesia of leg and foot (motor front, sensory back)

Question 20

What are four branches off the anterior cerebral A?

Answer 20

Recurrent A of heubner

Anterior communicating A

Anterior pericallosal A

Callosomarginal A

Question 21

What is the water-shed area of the cortex?

Answer 21

Part of the cortex supplied by anterior and middle cerebral A.

If there is an occlusion in either artery, this area will undergo damage

Question 22

What does the middle cerebral A supply?

Answer 22

Medial and lateral striate/thalamostriate, internal capsule, corpus striatum, and thalamus

Question 23

What are the branches off the middle cerebral A?

What do they supply?

Answer 23

Central A: primary motor and somesthetic cortices

Frontal branches: premotor and prefrontal cortices; broca’s speech area

Parietal branches: association cortex

Temporal branches: primary auditory cortex

Angular A: supramarginal and angular regions; wernicke’s area

Question 24

What do occlusions of the branches off the middle cerebral A cause?

Answer 24

Central A: contralateral spastic paralysis and/or paresthesia of the head and upper 1/2 of body

Frontal branches: broca’s aphasia (hear and comprehend but cannot appropriately respond= expressive language disorder

Parietal branches: interpretive disorders including body neglect, agnostic, and apraxia

Temporal branches: difficulty localizing sounds

Angular A: wernicke’s aphasia (fluent in speech but lacks content or meaning; inappropriate word choices= receptive language disorder

Question 25

What arteries and branches supply the posterior cerebral cortex?

Answer 25

Vertebral A: anterior spinal A, posterior spinal A, posterior inferior cerebellar A

Basilar A: anterior inferior cerebellar A, labyrinthine A, superior cerebellar A, posterior cerebral A

Question 26

What arteries supply the spinal cord?

Where are they located and what do they supply?

Where will a lesion to the SC interrupt blood flow?

Answer 26

Anterior spinal A: deep to anteromedian sulcus; supplies central gray matter and anteromedial portion of white matter

Posterior spinal A: branch off of vertebral A or PICA and run through posterolateral sulcus; supplies dorsal roots and posterior columns and peripheral margins of the cord

Where the SC is supplied by two arterial supplies: C2-3, T1-4, L1

Question 27

Where is the great anterior A of Adamkiewicz?

What does it supply?

How can this artery get damaged?

Answer 27

Arises from the L inferior intercostal or superior lumbar A and contributes to the anterior spinal A

Inferior 2/3 of the spinal cord

Can become compromised secondary to thoracolumbar fx or surgical repair of AAA -> ischemic necrosis of SC

Question 28

What causes central cord syndrome?

What are the S&S?

Answer 28

Disruption of blood flow to the anterior spinal A by:

Thrombosis, hyperextension injury of the neck, ischemia of central region of the SC

Abrupt onset, central necrosis and cavitation of the SC, sensory AND motor deficits to UE>LE, distal musculature > proximal musculature

Question 29

What does the posterior inferior cerebellar A supply?

What does an occlusion of the artery cause?

Answer 29

Posterior inferior portion of cerebellum, posterolateral aspect of the medulla, choroid plexus of the 4th ventricle

Lateral medullary syndrome/Wallenberg syndrome

Question 30

What does the anterior inferior cerebellar A supply?

Where is it located?

What CN is it by?

Answer 30

Anterior inferior portion of the cerebellum, superior and middle cerebellar peduncles, part of brainstem

Pontobulbar sulcus

CN VI, VII, VIII, flocculus of the cerebellum

Question 31

What does the superior cerebellar A supply?

Located?

Answer 31

Superior lateral portion of cerebellum, deep cerebellar nuclei, part of pons and midbrain

Posterior to CN III

Question 32

Where does the labyrinthine A come from?

What does it supply?

What does labyrinthinitis cause?

Answer 32

Branch of basilar A or off AICA

Main artery to the internal ear

Atherosclerosis or inflammation of the labyrinthine A resulting in irritation of the vestibulo-cochlear apparatus -> disturbs equilibrium and/or hearing

Question 33

What do the pontine branches supply?

Answer 33

Medial and lateral aspects of the pons

Distribute to regions of the brainstem in a “pie wedge” pattern -> sometimes seen with necrosis from a brainstem lesion

Question 34

What are branches off the posterior cerebral A?

What do they supply?

Answer 34

Penetrating branches: internal capsule, thalamus, choroid plexus of the lateral ventricle, upper midbrain

Temporal branches: inferior temporal cortex

Parietooccipital A: visual association cortex

Calcarine A: primary visual cortex

Posterior pericallosal A: anastomoses with the anterior pericallosal A of the anterior cerebral

Question 35

What causes an occlusion to the PCA?

What does this occlusion cause?

Answer 35

Thrombosis, compression due to uncal herniation

Ischemic necrosis of the primary visual cortex; contralateral homonymous hemianopsia with macular sparing

Question 36

What causes a falx herniation?

Symptoms?

Answer 36

If a unilateral space-occupying lesion is present -> the cingulate gyrus can herniate and push beneath the free edge of the falx cerebri

HA, contralateral leg weakness, no deficits

Question 37

What causes a uncal herniation?

What are the S&S?

What happens if the midbrain becomes involved?

Answer 37

If a unilateral space-occupying lesion is present -> the uncus can herniate and push though the tentorial notch

Compresses PCA and CN III: unilateral dilating pupil, CN III compression (oculomotor N palsy)

Contralateral hemiparesis and respiratory compromise; kernohan’s notch

Question 38

Kernohan’s Notch:

Uncal herniation causes pressure on the ____, causing _____.

The increased pressure pushes the brainstem into the _____, causing _____.

Answer 38

Ipsilateral brainstem

Contralateral limb weakness

Tentorium cerebelli

Ipsilateral limb weakness giving a false localizing sign

Question 39

What is a tonsilar herniation?

Answer 39

Cerebellar tonsils herniate through the foramen magnum and compress the medulla -> respiratory arrest

Acute and rapidly fatal

Question 40

What is an epidural hematoma?

Cause?

What are the S&S?

If not treated, what will it cause?

Answer 40

High pressure bleed expands the epidural space, separating the dura mater from the bone and creating a blood filled space

Fracture at the pterion ruptures the middle meningeal A running between the dura mater and the skull

Trauma -> initially unconscious -> rapid recovery -> few hours pass -> neurological symptoms…lens shape on MRI

Hematoma will press on the cerebral hemisphere and can lead to herniations (uncal herniation compress midbrain and decrease consciousness)

Question 41

What is a subdural hematoma?

Cause?

S&S?

What is the difference in causes between a child and an elderly patient?

Answer 41

Ruptured veins cause blood to accumulate in the subdural space

Head trauma causes cerebral veins to rupture as they cross the subdural space

Crosses suture lines on MRI; delayed symptoms due to slower pooling of blood, more acute onset, lethargy, seizures, HA

Children= skull fx
Elderly= fragile blood vessels

Question 42

What causes a subarachnoid hemorrhage?

Why?

How can test/know?

Answer 42

Rupture of a blood vessel in the subarachnoid space

Subarachnoid space contains all major blood vessels supplying the CNS

Presence of erythrocytes in the CSF

Sample CSF through lumbar puncture at L4-L5 (SC ends L2)