Ventricular system

Question 1

What are ventricles?

Answer 1

Ventricles are cerebrospinal fluid filled cavities within the brain.

Question 2

Lining of the ventricles

Answer 2

They are lined with ependymal cells and contain the choroid plexuses that produce CSF.

Question 3

List the ventricles

Answer 3

Two lateral ventricles
Third ventricle
Fourth ventricle

Question 4

Describe the lateral ventricles

Answer 4

Each cerebral hemisphere has one lateral ventricle
They are large C-shaped cavities
The two lateral ventricles communicate each other and with the 3 rd ventricle via the Interventricular foramina (Of Monro)

Question 5

Location of each part of the ventricles

Answer 5

Body → Parietal lobe
Anterior horn → Frontal lobe
Posterior horn → Occipital lobe
Inferior horn → Temporal lobe

Question 6

Extent of the body of the lateral ventricle

Answer 6

Extends from interventricular foramen to posterior end of the thalamus.

Question 7

Roof, Floor and Medial wall of the lateral ventricle

Answer 7

Roof → Formed by the undersurface of the genu of the corpus callosum
Floor → Formed by the head of the caudate nucleus
Medial wall → Formed by the septum pellucidum

Question 8

Relations of the anterior horn of the lateral ventricle

Answer 8

Roof → Formed by the undersurface of the genu of the corpus callosum
Floor → Formed by the head of the caudate nucleus
Medial wall → Formed by the septum pellucidum and the columns of the fornix

Question 9

Relations of the posterior horn of the lateral ventricle

Answer 9

Has a roof and a lateral wall.
Both of them are formed by fibres of the tapetum of corpus callosum

Question 10

Relations of the Inferior horn of the lateral ventricle

Answer 10

Roof → Formed by the corpus callosum, the tail of the caudate nucleus, and the amygdaloid body
Floor → Formed laterally by the collateral eminence and medially by the hippocampus

Question 11

What is the Choroid Plexus?

Answer 11

The choroid plexus projects into the ventricle on its medial aspect.
Choroid plexus is the lateral edge of the tela choroidea (which is a 2 – layered fold of pia mater) that contains blood vessels and is lined with ependyma.

Question 12

Function of the Choroid Plexus

Answer 12

Most of the CSF is produced by the choroid plexus of the lateral ventricles.

Question 13

What is the third ventricle

Answer 13

Slit like cleft between the two thalami

Question 14

Communications of the third ventricle

Answer 14

Anteriorly with the 2 lateral ventricles via the interventricular foramina (Of Monro)
Posteriorly with the 4 thventricle via the cerebral aqueduct (Of Sylvius)

Question 15

Anterior relation of the third ventricle

Answer 15

Thin sheet of grey matter, the lamina terminalis

Question 16

Posterior relation of the third ventricle

Answer 16

Posterior commissure, Cerebral aqueduct ▪ Roof – Fornix, Corpus callosum

Question 17

Floor of the third ventricle

Answer 17

Optic chiasma
Tuber cinereum
Infundibulum
Mammillary bodies

Question 18

Lateral Wall of the third ventricle

Answer 18

Thalamus, Hypothalamus

Question 19

What is the tela choroids?

Answer 19

Is a 2 layered fold of pia mater. The tela choroidea contains the choroid plexus of the 3rd ventricles.
Which is superior to a thin layer of ependyma in the roof, continuous with the wall of the ventricle

Question 20

List the 4 recesses within the third ventricle

Answer 20

Pineal recess
Suprapineal recess
Infundibular recess
Supraoptic recess

Question 21

What is the cerebral Aqueduct

Answer 21

Narrow channel that connects the 3rd and 4th ventricles
Traverses the midbrain
Surrounded by grey matter (Central grey)
No choroid plexus here

Question 22

What is the 4th ventricle

Answer 22

Tent shaped cavity
Anterior to the cerebellum and posterior to the pons and medulla
Continuous above with the cerebral aqueduct and below with the central canal of medulla and spinal cord

Question 23

Lateral relation of the 4th ventricle

Answer 23

Cranially – Superior cerebellar artery
Caudally – Inferior cerebellar peduncle

Question 24

Roof/ Posterior Relation of the 4th ventricle

Answer 24

Projects into cerebellum
Superior part – Superior cerebellar peduncle and superior medullary velum
Inferior part – Inferior cerebellar peduncle and inferior medullary velum

Question 25

Foramina of the 4th ventricle

Answer 25

Inferior medullary velum is pierced in the midline by a large aperture Foramen of Magendie
Lateral recesses – open anteriorly as the Foramina of Luschka
All these foramina open to the subdural space

Question 26

Choroid Plexus in the 4the ventricle

Answer 26

The choroid plexus is T shaped, with the stem of the doubled, as is suspended from the inferior half of the roof

Question 27

The floor of the Rhomboid Fossa.

Answer 27

The posterior surface of the pons
The posterior surface of the superior part of the medulla

Question 28

Describe the floor of the third ventricle/ Rhomboid Fossa (In relation to the median eminence)

Answer 28

The floor is divided into symmetrical halves by the median sulcus.
On either side of the sulcus is an elevation; the median eminence.
Lateral to the median eminence is the sulcus limitance, lateral to the vestibular area.
The vestibular nuclei lie beneath the vestibular area.
Facial colliculus is a swelling at the inferior end of each median eminence produced by fibers of the motor nucleus of the facial nerve looping around the abducent nerve nucleus.

Question 29

What is the striae medullaris?

Answer 29

Striae medullaris are strands of fibers arising from the arcuate nuclei and emerging from the median sulcus to pass over the median eminence and vestibular area to join the inferior cerebellar peduncle.

Question 30

What are the structures inferior to the striae medullaris in the rhomboid fossa?

Answer 30

Hypoglossal triangle – under which the hypoglossal nuclei
Vagal triangle – The dorsal motor nucleus of the Vagus nerve lies underneath
Area postrema

Question 31

Where is CSF secreted?

Answer 31

CSF is secreted by the choroid plexus of the lateral, 3rd, and 4th ventricles.
Some CSF is also produced by the ependymal cells lining the ventricles and by brain matter.