Ventricular System and CSF Flashcards
The interior of the brain contains a series of cavities. The cerebrum contains a median cavity, the third ventricle, and two lateral ventricles, one in each hemisphere. Each lateral ventricle opens into the third ventricle through an ____(a)____. The third ventricle is continuous caudally with the ____(b)____, which traverses the midbrain and opens into the ____(c)____. The ____(c)____ is situated dorsal to the pons and medulla and ventral to the cerebellum. It communicates inferiorly, with the ____(d)____, which traverses the lower part of the medulla and the spinal cord. The entire ventricular system is lined by an epithelial layer called the ____(e)____.
(a) interventricular foramen
(b) cerebral aqueduct
(c) fourth ventricle
(d) central canal
(e) ependyma
[Diagram]
The Lateral Ventricles
(a) Name the four parts of the lateral ventricle and the lobe of cerebral hemisphere that each is located in.
(b) The ________ of the lateral ventricle is the site of confluence of the body, posterior and inferior horns. It is the most dilated part of the lateral ventricle.
(a) body: parietal lobe, anterior horn: frontal lobe, posterior horn: occipital lobe, inferior horn: temporal lobe
(b) atrium (trigone)
The Lateral Ventricles
The central part of the lateral ventricle is elongated anteroposteriorly. Anteriorly, it becomes continuous with the anterior horn at the level of the interventricular foramen. Posteriorly, the central part reaches the ____(a)____
of the corpus callosum.
The central part is triangular in cross section. It has a roof, a floor, and a medial wall. The roof is formed by the ____(b)____. The medial wall is formed by the ____(c)____ and by the body of the fornix. The floor is formed mainly by the superior surface of the ____(d)____ medially, and by the ____(e)____ laterally. Between these two structures, there are the ____(f)____ laterally and the ____(g)____ vein medially. There is a space between the fornix and the and the upper surface of the ____(d)____. This is the ____(h)____ which is C-shaped.
(a) splenium
(b) trunk of the corpus callosum
(c) septum pellucidum
(d) thalamus
(e) caudate nucleus
(f) stria terminalis
(g) thalamostriate
(h) choroid fissure
More diagrams: [Relations of the lateral ventricle]
The Lateral Ventricle: Anterior horn
This horn is triangular in section.
(a) roof
(b) anterior wall
(c) floor
(d) medial wall
(a) anterior part of trunk of corpus callosum
(b) genu of corpus callosum
(c) head of caudate nucleus (main) and upper surface of rostrum of corpus callosum near the midline
(d) septum pellucidum
[Diagram: relations of the anterior horn of the lateral ventricle]
Further notes:
It must be noted that the tela choroidea and the choroid plexus do not extend into the anterior horn.
The Lateral Ventricle: Posterior horn
The posterior horn of the lateral ventricle extends backwards into the occipital lobe. It has a roof, a lateral wall, and a medial wall. The roof and lateral wall are formed by the ____(a)____. The medial wall shows two elevations. The uppermost of these is the ____(b)____, which is produced by fibres of the forceps major, as they run backwards from the splenium of the corpus callosum. The lower elevation is called the ____(c)____. It represents white matter “pushed in” by formation of the calcarine sulcus.
(a) tapetum [a sheet of fibres from the splenium of the corpus callosum]
(b) bulb of the posterior horn
(c) calcar avis
[Diagram]
State the boundaries of the 3rd ventricle.
Lateral wall: medial surface of thalamus and medial surface of hypothalamus (a small part of it by the epithalamus)
Anterior wall: lamina terminalis mainly (upper part formed by the anterior commissure and columns of fornix).
Posterior wall: epithalamus consisting of pineal body, posterior commissure and habenular commissure.
Floor: optic chiasma, tuber cinereum, infundibulum, mammillary bodies, posterior perforated substance, tegmentum of midbrain.
Roof: ependyma that stretches across the two thalami.
Further notes:
Above the ependyma, there’s the tela choroidea with choroid plexuses of the third ventricle.
Click on Answer to view diagrams of the various subarachnoid cisterns.
Briefly discuss the Foramina of Luschka.
[State their location and where they drain.]
The Foramina of Luschka, also known as the lateral apertures, are two openings located at the lateral-most aspect of the fourth ventricle.
They drain into the subarachnoid space at the cerebellopontine angle cistern immediately posterior to the root of the glossopharyngeal (IX) nerve.
Briefly discuss the Foramen of Magendie.
[State its location and where it drains into.]
The Foramen of Magendie, also known as the median aperture, is a single opening located in the midline in the inferior aspect of the roof of the fourth ventricle, caudal to the nodule of the cerebellum.
It drains CSF from the fourth ventricle into the cisterna magna.
