Ventricular System

Question 1

Answer 1

Question 2

Location of the fourth ventricle

Answer 2

On the dorsal surface of the brainstem beneath the cerebellum

Question 3

Shape of the fourth ventricle

Answer 3

Rhomboid

Question 4

What is found on each side of the fourth ventricle

Answer 4

Lateral recess which extends towards the lateral margin of the brainstem and is continuity through a small lateral aperture with the subarachnoid space of the CPA (Foramen of Luschka)

Question 5

Foramen Luschka

Answer 5

Lateral communication between fourth ventricle in arachnoid space of CPA.

Question 6

Structure of the roof of the fourth ventricle?

Answer 6

For the most part, the roof is made up of the cerebellum.

However, the roof of the caudal part consitsts of pia and ependyma, a central defect in which constitutes the median aperture or foramen Magendie, which provides communication between the ventricle and the cisterna magna of the subarachnoid space.

The rostral part of the roof of the fourth is partly formed by the superior cerebellar peduncles on either side, with the space between them bridged by the thin superior medullary velum

Question 7

Foramen of Magendie

Answer 7

Median aperture of fourth ventricle at its caudal end which allows communication with the cisterna magna

Question 8

Answer 8

Question 9

Answer 9

Foramen of Magendie

Question 10

Rostral extent of the fourth ventrcile

Answer 10

Extends as far as the pontomesencephalic junction, where it becomes continuous with the cerebral aqueduct.

Question 11

Location of cerebral aqeuduct

Answer 11

Passes throughout the length of the midbrain, beneath the inferior and superior colliculi (tectum)

Question 12

Walls of the third ventricle

Answer 12

Thalamus and hypothalamus

Question 13

Intermediate mass/commsiure

Answer 13

Adhesion between the medial surfaces of the two thalami across the third ventircle

Question 14

Roof of the third ventricle

Answer 14

Pia-ependyma which spans between the two nerve fibre bundles, striae medullaris thalami which are situated along the dorsomedial bordder of the thalamus.

Question 15

Location of the foramen Monro

Answer 15

Between the column of the fornix and the anterior pole of the thalamus

Question 16

Def: anterior horn

Answer 16

Part of the lateral ventricle lying anyerior to the interventricular foramne.

Question 17

Lateral wall of the anterior horn of the lateral ventricle

Answer 17

Head of the caudate nucleus

Question 18

Medial wall of lateral ventricle

Answer 18

Septum pallucidum

Question 19

Floor of the body of the lateral ventricle

Answer 19

Thalamus

Tail of the caudate nucleus.

Question 20

What is found in the floor of the inferior horn

Answer 20

Hippocampus

Question 21

What is found in the roof of the temporal horn of the lateral venrricle

Answer 21

Attenuated tail of caudate nucleus

Question 22

Location of the choroid plexus

Answer 22

Lateral, third, fourth ventricles.

Question 23

Formation of the choroid plexus

Answer 23

Formed by the invagination of the vascular pia mater into the ventricular lumen, where it becomes highly convoluted, producing a sponge like appearance.

Question 24

Entry of the choroid plexus to the third and fourth ventricles

Answer 24

Through their roofs.

Question 25

Entry of the choroid plexus to the lateral ventricles

Answer 25

Through the choroid fissure, along the line of the fornix

Question 26

Volume of CSF

Answer 26

150mL

Question 27

Answer 27

Question 28

Where is most CSF produced

Answer 28

In the lateral ventricle by the choroid plexus

Question 29

Flow of CSF out of the fourth ventricle

Answer 29

Most flows through the foramen of Magendie into the cisterna magna. Some flows through the foramen of Luschke to enter the subarachnoid space in the CPA. Some flows down the spinal canal

Question 30

How is CSF reabsorbed into the venous system

Answer 30

By passing into dural venous sinuses, principally the superior sagittal sinus via arachnoid villi

Question 31

Features of the arachnoid villi

Answer 31

Consist of invaginations of arachnoid mater through the dural wall and into the lumen of the superior sagittal sinus.

Question 32

What determines reabsorption of CSF at the arachnoid villi

Answer 32

Hydrostatic pressure in the subarachnoid space is higher than that in the lumen of the sinus because of the greater colloid omotic pressre of venous blood compared to CSF.