4th ventricle

4th ventricle

1. Dr. Rati Tandon
J.N.M.C.,AMU,
ALIGARH

2. tent-like cavity of hindbrain
situated in the posterior cranial fossa.
triangular outline in sagittal section and appears
rhomboidal in shape in horizontal section.

3. Behind the pons and
the upper part of
medulla oblongata.
in front of the
cerebellum

4. Important features:
recesses,
angles,
boundaries,
choroid plexus.

5. RECESSES
Five in number:
Two lateral recesses
Median dorsal recess
Two lateral dorsal
recess

6. ANGLES
Superior angle is continuous above with the cerebral
aqueduct of midbrain.
Inferior angle is continuous below with the central canal of
the closed part of the medulla oblongata.
Two lateral angles - lateral recess.

7. BOUNDARIES
•On each side, the
fourth ventricle is
bounded,
–Inferolaterally by
inferior cerebellar
peduncle,
supplemented by
gracile and cuneate
tubercles, and
•Superolaterally, by
superior cerebellar
peduncle

9. ROOF
Upper part:-
convergence of two
superior cerebellar
peduncles and
a thin sheet of white
matter, the superior
medullary velum.

10. Lower part:
-Inferior medullary
velum.
-Median aperture of
Magendie.
-T-shaped choroid
plexus.

11. FLOOR (RHOMBOID FOSSA)
rhomboid in shape (diamond-shaped).
formed by posterior surfaces of the pons and the
upper part of the medulla.

12. Three parts:
A] Upper triangular part - The posterior surface
of the pons.
B] The lower triangular part - the upper part of
the posterior surface of the medulla.
C] The intermediate part at the junction of the
medulla and pons.

14. FEATURES OF THE FLOOR OF
FOURTH VENTRICLE
Median sulcus.
Medial eminence.
Medial eminence is
bounded laterally by
sulcus limitans.

15. lateral to sulcus
limitans. overlies the
vestib-ular nuclei, hence
it is termed vestibular
area.
Superior fovea - upper
end of sulcus limitans
widens into a triangular
depression.

16. Above the superior fovea
the sulcus limitans
flattens out and presents
a bluish grey area called
locus ceruleus.
The lowermost part of
sulcus limitans presents
a small depression called
inferior fovea.

17. •On either side, the medial eminence, an oval
swelling, facial colliculus.

18. •Sulcus divides the
medial eminence, the
hypoglossal triangle
above and the vagal
triangle below.
•The features of the lower
part of the floor of fourth
ventricle resemble with
that of a pen-nib, hence
it is called calamus
scriptorius

19. The inferolateral
margins -Marked by a
narrow white ridge
called taenia.

The two taenia meet
at the inferior angle
of the ventricle to
form a small fold called
obex.

The term obex is often
used to denote the
inferior angle of the
fourth ventricle.

20. THANK YOU