Ventricles, CSF, and Hydrocephalus

Question 1

Where are the lateral ventricles located?

Answer 1

Telencephalon

Question 2

What is the opening between the lateral ventricles and the 3rd ventricle?

Answer 2

Interventricular foramen (of Monro) in diencephalon (between thalami and hypothalamus)

Question 3

What is the opening between the 3rd ventricle and the 4th ventricle?

Answer 3

Cerebral aqueduct (of Sylvius) in midbrain, narrowest part

Question 4

What is the opening between the 4th ventricle and the subarachnoid space?

Answer 4

Foramina of Luschka (lateral, 2), and foramina of Magendie (medial, 1)

Question 5

What happens to CSF after it enters the subarachnoid space?

Answer 5

Reabsorbed by arachnoid granulations into dural venous sinuses

Question 6

If you can see the lateral ventricles in a saggital brain CT, what level are you at?

Answer 6

At telencephalon level of cerebral cortex

Question 7

If you can see the 3rd ventricle in a saggital brain CT, what level are you at?

Answer 7

Level of the thalami

Question 8

If you can see the 4th ventricl in a saggital brain CT, what level are you at?

Answer 8

Level of the pons

Question 9

What is hydrocephalus?

Answer 9

Increased ICP and ventricular dilation due to excessive amount of CSF in ventricles/subarachnoid spaces

Question 10

What types of hydrocephalus are there?

Answer 10

Non-communicating (obstructive) or communicating (non-obstructive)

Question 11

What can cause communicating (non-obstructive) hydrocephalus?

Answer 11

Overproduction of CSF (rare) or under-absorption of CSF

Question 12

What can cause non-communicating (obstructive) hydrocephalus?

Answer 12

Obstruction of outflow

Question 13

What are causes of aqueductal stenosis?

Answer 13

Usually inherited (can be x-linked), can be due to pineal tumor, scarring from previous meningitis, or inflammation from intrauterine infection

Question 14

What is normal pressure hydrocephalus?

Answer 14

Form of communicating hydrocephalus. CSF failing to drain properly leading to enlarged ventricles. Can be due to increased CSF viscosity or impaired CSF absorption

Question 15

What is the triad seen with normal pressure hydrocephalus?

Answer 15

Wet, wacky, wobbly (urinary incontinence, cognitive impairment/confusion, unsteady gait)

Question 16

What is Dandy-Walker malformation?

Answer 16

4th ventricle outlet obstruction. Cyst enlarges during development, presses on cerebellum which prevents it from forming, non-communicating hydrocephalus (fluid accumulates above 4th ventricle)

Question 17

What is Chiari II?

Answer 17

Herniation of cerebellar vermis and tonsils through foramen magnum, associated with lumbosacral myelomeningocele). Non-communicating hydrocephalus (fluid accumulates above 4th ventricle)