Neuroanatomy

1. MENINGES OF BRAIN
AND SPINAL CORD
Presented By:
Dr. Md. Saiduzzaman
MD Resident
(Neurology, Phase B)

2. TheMeninges
• The Meninges are the
membranes covering
the brain and spinal
cord.
• Itconsist of three
layers:
1. Thedura mater,
2. Thearachnoid mater,
3. Thepia mater.

3. TheMeninges

4. Dura mater
Outer strong layer.
 Literally means “Tough Mother”.
Two layers:
1. Outer Fibrous/Endosteal layer.
2. Inner Meningeal/ Cellular layer.
(Lined by Simple squamous epithelium)
Theseare closely united except along certain lines, where
they separate to form venous sinuses.

6. DURA MATER
> Endosteal layer :
o Periosteum - inner surface of the skull bones
o Not continuous with dura mater of spinal cord
> Meningeal layer :
o Continuous with dura mater of spinal cord
o Folded inwards as4 septa between part of the
brain
o The function of these septa isto restrict the rotatory
displacement of the brain.

7. Duramater(Cont…)
Folds of Dura mater -
a.Falx cerebri
b.Falx cerebelli
c.Tentorium cerebelli
d.Diaphragma sella

8. Sagittalsectionshowingthe duramater
1) Falxcerebri
2) Tentorium
cerebelli
3) Falx
cerebelli
4) Diaphragmasellae

9. Superiorview showingthe duramater
1) Falxcerebri
2)Tentorium
cerebelli

10. Coronalsectionof the upperpart of thehead
Endosteallayer
Meningeallayer
Theyare closely
united exceptalong
certain lines;they
are separatedto
form venous
sinuses
Superiorsagittalsinus
(Dural venoussinus)
Dura mater
Subduralspace

11. TheFalxCerebri
• It is a sickle-shaped fold of dura mater that lies in
the midline between two cerebral hemispheres.
• Its narrow end in front is attachedto the internal
frontal crest and the crista galli.
• Its broad posterior part blends in the midline with the
upper surface ofthe tentorium cerebelli.
• The superior sagittal sinus runs in its upper fixed
margin, the inferior sagittal sinus runs in its lower
concave free margin, and the straight sinus runs along
its attachment to the tentorium cerebelli.

12. FalxcerebriSuperiorsagittalsinus
Inferior
sagittalsinus Straight
sinus
Tentorium
cerebelli
*
Frontalcrest
Cristagalli

13. TheTentorium Cerebelli
• Thetentorium cerebelli
is acrescent-shaped
fold of dura mater that
roofs over the posterior
cranial fossa.
• It covers the upper
surface of the
cerebellum and
supports the occipital
lobes of the cerebral
hemispheres.

14. Tentorium
cerebelli
Falxcerebri

15. TheFalxCerebelli
• The falx cerebelli is a small, sickle-shaped fold
of
dura mater that is attached to the internal
occipital crest and projects forward between
the two cerebellar hemispheres.
• Its posterior fixed margin contains the occipital
sinus.

16. TheDiaphragma Sellae
• Thediaphragma sellae is asmall circular fold of
dura mater that forms the roof for the sella
turcica.
• A small opening in its center allowspassage
of the stalk of the pituitary gland.

19. Dural Nerve Supply
• Branchesof the trigeminal, vagus,and first
three cervical nerves and branches from
the sympathetic system passto the dura.
• Thedura is sensitive to stretching,which
produces the sensation of headache.

20. Dural Blood Supply
Arterial Supply
• Thedura mater is supplied by the internal carotid,
maxillary,ascending pharyngeal, occipital, and vertebral
arteries.
• From aclinical standpoint, the most important is the
middle meningeal artery, which is commonly damaged
in head injuries.

21. VenousDrainage
• Themeningeal veins lie in the endosteal layer ofdura.
• Themiddle meningeal vein follows the branches ofthe
middle meningeal artery and drains into the
pterygoid venous plexus or the sphenoparietalsinus.
• Theveins lie lateral to the arteries.

22. Arrachnoid mater
 Delicate, impermeable & avascular membrane
covering the brain.
 Lying between Piamater (internally) & dura
Mater(externally).
 Separated from dura mater bya potential space, the
subdural space(filled by afilm of fluid).
 Separated from pia mater bythe subarachnoid space
(filled with CSF).
 The outer and inner surfaces covered with
flattened mesothelial cells

23. Superior
cerebral
veins
beneath
arachnoid
Arachnoid mater

24. Arachnoid mater
Arachnoid villiArachnoidmater
Subarachnoidspace
Arachnoid
granulations
Subduralspace

25. Pia Mater
> The pia mater is a vascular membrane covered by
flattened mesothelial cells, closely attached to the
brain,covering the gyri and descending into the sulci.
> It extends out over the cranial nerves and fuses
with their epineurium.

26. MENINGES OF THE SPINAL CORD
Dura Mater
Encloses the spinal cord and the cauda equina.
 It is continuous above through the foramen
magnum with the meningeal layer of dura covering
the brain.
> Inferiorly, it ends on the filum terminale at the level
of the lower border of the second sacral vertebra.

29. • Subdural space is
a potential space
where superior
cerebral veins
traverse to reach
the superior
sagittal sinus and
its lacunae.
Superiorcerebral veins
beneath dura
Subdural Space

30. Subduralhaematoma
Dura
Arachnoid

34. Subarachnoid Space:
 Relatively narrow over the surface of cerebral
hemisphere, but sometimes becomes much widerin
areas at the baseof the brain, the widest spaceis
called subarachnoidcisterns.
 Thecisterna cerebellomedularis lies between inferior
surface of the cerebellum and roof of4th ventricle.
 Thecisterna interpeduncularis lies between 2cerebral
hemispheres. All the cisternae are in free
communication with one another & with the
remainder of subarachnoidspace.

35. Median sagittalsectionto showthe subarachnoidcisterns&
circulationof CSF
Superior
cistern
Interpeduncular
cistern
Cerebellomedullarycistern
Chiasmatic
cistern
Pontine
cistern

38. Hydrocephalus
Hydrocephalus is an abnormal increase in
the volume of the CSF within the skull.
 It is due to one of the following:
(1) an abnormal increase in the formation
of the fluid,
(2) blockage of the circulation of the fluid,
(3) diminished absorption of the fluid.

39. Hydrocephalus (cont….)
Types:
1. Non-communicating/ Obstructive
(blockage at some point between its formation at the
choroid plexuses and its exit through the foramina in
the roof of the fourth ventricle.)
2. Communicating.