1) Blood Supply And Ventricles

Question 1

What produces CSF? Specifically what areas?

Answer 1

The choroid plexus

Primarily lateral ventricles & 4th ventricle

Question 2

What is the location of each of the 4 interconnected ventricles?

Answer 2

Lateral x2 - in each cerebral hemisphere

Third ventricle -> between thalami

4th ventricle -> between cerebellum & pons

Question 3

This one’s a doozy…

What’s the path of CSF to the venous system?

Answer 3

Lateral ventricles > interventricular foramina of monroe > 3rd ventricle > cerebral aqueduct > 4th ventricle (can go to central canal of spinal cord from here) but to the brain venous system > median & lateral aperatures > subarachnoid space > arachnoid granulations > superior saggital venous sinus

Question 4

What is the increase in cerebral mass/size due to presence of excessive CSF known as?

Answer 4

Hydrocephalus

Question 5

If the ventricles are normal size and compression of the CNS is occurring, where is the CSF accumulating?

What disease is this most commonly associated with?

Answer 5

In the subarachnoid space is where the CSF is

This is known as external/communicating hydrocephalus

Alzheimer’s disease

Question 6

What is it called if the CSF isn’t draining but stays in the ventricles?

Answer 6

Internal/noncommunicating hydrocephalus.

Question 7

Which CN is usually the first to be affected by hydrocephalus?

Answer 7

Abducent (VI)

• no LR activity
• internal strabismus

Question 8

What is batson’s plexus?

Answer 8

Internal venous plexus: Receives drainage from veins in the spinal cord, it is in the epidural space, and empties into intervertebral veins and then segmental veins

Question 9

What does the internal cerebral vein drain, and drain to?

Answer 9

It receives thalamostriate and anterior septal veins.

Drains into great vein of Galen.

Question 10

Okay… just study the veins in the brain

Answer 10

Do it.

Question 11

What are the 3 locations in the brain where there is no blood brain barrier?

Answer 11

Pineal body
Area postrema
Median eminence of hypothalamus.

Question 12

What is the purpose of astrocytes in the brain?

Answer 12

Secrete paracrines that promote tight junction formation, which prevent solute movement between endothelial cells.

Question 13

What is the clinical presentation of occlusion of the anterior cerebral artery?

Answer 13

Contralateral paresis and/or parasthesia of the leg and foot
SENSATION & MOTOR TO THE LOWER EXTREMITIES

Question 14

Branches of the middle cerebral artery (its a big one)?

Answer 14

Central artery - Primary motor
Frontal branches - premotor & prefrontal cortices. broca’s speech area (usually on left side)
Partietal branches - Association cortex
Temporal branches - Primary auditory
Angular artery - Wernicke’s area (usually left side)

Question 15

Clinical presentation of middle cerebral artery occlusions, based on branches?

Answer 15

Central artery > contralateral spastic paralysis, and paresthesia of head and upper 1/2 of body

Frontal branches > broca’s aphasia = can hear and comprehend but cannot respond

Parietal branches > Body neglect, agnosia, and apraxia

Temporal branches > difficulty localizing sounds

Angular artery > Wernicke’s aphasia = fluent in speech, but lacks meaning

Question 16

What is impaired if you have ischemic necrosis of the spinal cord in the inferior 2/3?

Answer 16

Blood flow thru the great anterior artery of adamkiewicz is impaired

It is the main supply to the inferior 2/3 of the spinal cord

Question 17

What is central cord syndrome caused by?

How does it clinically present?

Answer 17

Disruption of blood flow to the anterior spinal artery.
Thrombosis or hyperextension injury of the neck.
Lose function in upper extremity more than lower, and distal musculature more than proximal

Question 18

What is the cause of wallenberg syndrome (lateral medullary syndrome)?

What is wallenberg syndrome?

Answer 18

Occlusion of the posterior inferior cerebellar artery (branch of vertebral artery).

Loss of sensation, pain and temperature specifically.

Question 19

What is the main artery of the internal ear?

What happens if injured

Answer 19

Labyrinthine artery - branch of basilar artery, or off of AICA
Disturbs equilibrium and/or hearing

Question 20

What happens if the posterior cerebral artery is occluded?

Answer 20

Contralateral homonymous hemianopsia with macular sparing

Question 21

What separates the two hemispheres?

Answer 21

Falx cerebri

Question 22

If the falx cerebri is damaged what’re the clinical symptoms?

Answer 22

Headache, contralateral leg weakness… may not be clinically presenting at all!!!!

Question 23

What does an uncal (tentorial) herniation cause?

Answer 23

CN III compression/palsy

Question 24

What does tonsilar herniation lead to?

Answer 24

Respiratory arrest

cerebellar tonsils herniate through formamen magnum

Question 25

During an epidural hematoma which space is pushed open by accumulating blood?
Which artery is usually the cause?

Answer 25

Pushes the dura mater from the bone, expanding the epidural space.
Treat by evacuation of the hematoma.
Middle meningeal A. at the pterion.

Question 26

What is the cause of a subdural hematoma?

How does it present?

Answer 26

Head trauma causes cerebral veins to rupture as they cross the subdural space.
More insidious than epidural, slower bleed. Leads to lethargy, seizures, or headaches.

Question 27

Subarachnoid hemorrhage is caused by what?

Answer 27

All major blood vessels supplying the CNS run in the subarachnoid space, can detect with a lumbar puncture detecting blood.