Ventricle CSF & Hydrocephalus

Question 1

How much CSF is produced each day?

Answer 1

400-500 ml/day

Question 2

CSF: Function

Answer 2

• Helps provide homeostasis, protection and buoyancy
• Prevents weight of brain from compression CNs and vasculature at the base of the skull
• Helps remove brain metabolites
• Endocrine mechanism – hormone transport

Question 3

What produces CSF?

Answer 3

Ependymal cells in the choroid plexus (60-80%) – lateral ventricle (65% produced here), 3rd ventricle, 4th ventricle

Question 4

Choroid Plexus

Answer 4

Consists of villous folds lined by epithelium with a central core of highly vascularized connective tissue

Question 5

Choroidal Epithelium

Answer 5

Specialized layer of Ependymal cells that overlies villi in the Choroid Plexus

Question 6

Main difference in composition of CSF compared to serum:

Answer 6

CSF has 0.035 g/dL protein vs. Serum has 7 g/dL protein

Question 7

How do you test CSF composition?

Answer 7

Lumbar puncture

Question 8

CSF Circulation

Answer 8

(1) Produced in Choroid Plexus of Lateral Ventricles
(2) Enters 3rd Ventricle via R and L Interventricular Foramen (of Monro)
(3) Enters 4th Ventricle via Cerebral Aqueduct of Sylvius
(4) Once in 4th Ventricle can enter Subarachnoid space via: Foramen of Luschka or Foramen of Magendie
(5) CSF reabsorbed by arachnoid granulations in the dural venous sinuses

Question 9

Foramen of Luschka

Answer 9

• Two are located in the Fourth Ventricle
• Lateral Apenture

Question 10

Foramen of Magendie

Answer 10

• One located in Fourth Ventricle
• Medial aperture

Question 11

Arachnoid Granulations

Answer 11

Extensions of the Arachnoid Mater that allow CSF to be absorbed by the Dural Sinuses

Question 12

Subarachnoid Cisterns

Answer 12

• Soft tissue structures that contain CSF and “anchor” the brain
• Consists of arachnoid trabeculae, vasculature, and in some instances CN roots

Question 13

Cerebellomedullary Cistern (Cisterna Magna)

Answer 13

• Largest subarachnoid cistern
• Located between cerebellum and medulla
• Receives CSF from apertures of 4th ventricle

Question 14

Interpeduncular Cistern (Basal Cistern)

Answer 14

Interpeduncular fossa between cerebral peduncles of midbrain

Question 15

Pontocerebellar Cistern (Pontine Cistern)

Answer 15

• Located ventral to the Pons
• Continuous inferiorly with spinal subarachnoid space

Question 16

Quadrigeminal Cistern (Cistern of Great Cerebral Vein)

Answer 16

• Located between the Posterior Corpus Callosum and superior surface of the Cerebellum
• Contains part of great vein of Galen

Question 17

Posterior Cerebellomedullary Cistern

Answer 17

Located inferior to the Cerebellum

Question 18

Cistern

Answer 18

Enlarged portions of subarachnoid space taht contain arteries, veins, CN roots and CSF

Question 19

Blood supply to Choroid Plexus in Lateral and 3rd Ventricles:

Answer 19

Anastomosis between Anterior Choroidal Artery (ICA), Lateral Posterior Choroidal A (BA), and Medial Posterior Choroidal A (BA)

Question 20

Blood supply to Choroid Plexus in 4th Ventricle:

Answer 20

AICA (BA) and PICA (VA)

Question 21

Hydrocephalus

Answer 21

Increased amounts of intracranial pressure (ICP_ and ventricular dilation due to an excessive amount of CSF accumulation in the ventricles and/or subarachnoid spaces

Question 22

Communicating (Nonobstructive) Hydrocephalus

Answer 22

• Failure to reabsorb CSF
• Communication between the ventricles and the subarachnoid space is intact
• Usually caused by a deficiency in the absorption of CSF into the sinus – can happen as a result of damage to the arachnoid granulations (ex. consequence of purulent bacterial meningitis)
• CSF still produced and circulates normally, but absorption into the venous sinus is impaired

Question 23

Non-Communicating (Obstructive) Hydrocephalus

Answer 23

• Failure to circulate CSF to Subarachnoid Space
• Excessive amounts of CSF in the cerebral ventricles and enlargement of the head
• Caused by overproduction of CSF, obstruction of CSF flow, or interference with CSF absorption
• Dilates the ventricles, thins the cerebral cortex, and separates the bones of the calvaria in infants
• Obstruction can occur at any place but typically occurs in the Cerebral Aqueduct or an Interventricular Foramen

Question 24

Communicating Hydrocephalus on MRI

Answer 24

Accumulation of CSF in subarachnoid space

Question 25

Noncommunicating Hydrocephalus on MRI

Answer 25

CSF not draining out of ventricles so see enlarged ventricles

Question 26

Internal Hydrocephalus

Answer 26

Accumulation of CSF in internal structures like ventricles – internal to brain

Question 27

External Hydrocephalus

Answer 27

• Accumulation of CSF on external surface like Subarachnoid Space – external to brain
• More common in Communicating Hydrocephalus

Question 28

Hydrocephalus Shunts

Answer 28

• Can be a permanent fix for Non-communicating Hydrocephalus
• Shunts CSF from ventricles to stomach

Question 29

Result of stenosis of Cerebral Aqueduct:

Answer 29

• Enlarged Lateral Ventricle
• Enlarged 3rd Ventricle
• Normal 4th Ventricle

Question 30

Cranial Nerves Affected by Hydrocephalus:

Answer 30

• CN III
• CN IV
• CN VI
  *associated with eye muscle control

Question 31

Sundown Gaze

Answer 31

• Can produce strabismus (misalignment of the eyes) and diplopia
• Caused by Abducens Palsy

Question 32

Chaiasmatic Cistern (Cistern of Optic Chiasm)

Answer 32

• Located inferior and anterior to Optic Chiasm

Question 33

Cisterna Ambiens (Ambient Cistern)

Answer 33

• Located on lateral aspect of Midbrain
• Continuous posteriorly with Quadrigeminal Cistern

Question 34

Glomus Choroideum

Answer 34

Large, expanded portion of choroid plexus found in area of atrium