Ventricles, CSF & Hydrocephalus (Stephens)

Question 1

What compromises the ventricular system

Answer 1

2 Lateral Ventricle

Third Ventricle

Fourth ventricle

Question 2

What drains the CSF from the lateral ventricles to the third ventricle

Answer 2

Interventricular foramen of Monroe

Question 3

What drains the CSF from the third ventricle to the fourth ventricle

Answer 3

Cerebral aqueduct

Question 4

How does CSF from the fourth ventricle get to the subarachnoid space

Answer 4

Lateral & Median apeture

Question 5

Where is cerebral spinal fluid produced

Answer 5

Choroid plexus of the lateral, third and fourth ventricles

Question 6

Route of CSF

Answer 6

Lateral ventricle –> (interventricular foramen) –> Third ventricle –> (cerebral aqueduct) –> fourth ventricle –> (lateral & median apeture) –> subarachnoid space —> arachnoid villi –> Superior sagittal sinus

Question 7

Volume of CSF in humans

Answer 7

20-25 ml in ventricles

140 ml in system

600-700 ml/day (replaced every 8 hrs)

Question 8

Hydrocephaly

Answer 8

Due to an excessive amount of CSF in the ventricular system, the subarachnoid space or both.

Question 9

External Hydrocephaly

Answer 9

Excessive accumulation of CSF in the subarachnoid space. It may be supratentorial, infratentorial or both.

Question 10

What is supratentoral external hydrocephalus

Answer 10

Accumulation of CSF above the tentorium cerebelli. Most commonly associated with senile atrophy of the cortex, e.g., Alzheimer’s disease (aging)

Question 11

What is infratentorial external hydrocephalus

Answer 11

Accumulation of CSF below the tentorium cerebelli. It is seen in combination with internal (noncomminucating) hydrocephalus to pr

Question 12

Internal hydrocephalus (noncommunicating hydrocephalus)

Answer 12

Blockage of CSF in the ventricular system. CSF does not drain into the subarachnoid space.

Question 13

What does internal (noncommunicating) hydrocephlaus result in

Answer 13

Enlargement of the ventricles proximal to the obstruction. It may be present in combination with an infratentorial external hydrocephalus

Question 14

What are the clinical signs of hydrocephalus

Answer 14

1. Internal strabismus (abducens palsy)
2. “Sundown eyes”
3. Papilledema

Question 15

Communicating Hydrocephalus

Answer 15

No blockage in ventricular system

Combination of infratentorial external and internal (noncommunicating) hydrocephalus

CSF is able to move through the ventricular system into the infratentorial subarachnoid space, but it cannot circulate to the arachnoid villi to get to the superior sagittal sinus

Question 16

Cerebral spinal fluid is resorbed in the

Answer 16

arachnoid villi

Question 17

Atrophy of the cerebral cortex may result in

Answer 17

External hydrocephalus

(specifically supratentoral external hydrocephalus)

Question 18

Occlusion of the cerebral aqueduct would result in _____ of the ______ and _______

Answer 18

Hydrocephalus

Lateral ventricles

3rd

NOTE: Cerebral aqueduct drains the 3rd ventricle to the 4th ventricle so its blockage would lead to hydrocephalus of the lateral & 3rd ventricles

Question 19

Occlusion of the right interventricular forman would result in _________ of the _________

Answer 19

Hydrocephalus

lateral ventricle

Question 20

Obstruction of the subarachnoid space at the level of the tentorial notch may result in

Answer 20

Communicating hydrocephalus

Question 21

CSF eneters the subarachnoid space via what

Answer 21

Medial & Lateral foramina

Question 22

Secondary to a subarachnoid hemorrhage blood in the CSF may occlude the ____ and result in ____

Answer 22

Arachnoid villi

Secondary (chemical) meningitis

Question 23

What are you seeing in this image

Answer 23

Internal hydrocephalus due to enlargement of the lateral ventricles which is caused by obstruction of interventricular foramina of Monroe bilaterally and/or cerebral aqueduct.