Meninges & and CSF

Description of meninges & circulation of CSF for the students of first year In the subject Anatomy.

1. MENINGES
Outer to inner
Dura mater (mother) Arachnoid Pia
(Pachymeninx)
Leptomeninges
( Delicate)
Leptomeninges
( Delicate)

2. Dura Mater
•Thickest , inelastic , dense
•Outer surface is rough & inner smooth
•Cranial & spinal layers-Unite at foramen magn um
Cranial Spinal
Inner
Outer
Inner Meningeal
Outer Endosteal
FalxcerebriTentorium
cerebelli
Falx
cerebelli
Diaphragma
sellae

3. •The endosteal & meningeal layers are united except where
they enclose venous sinuses.
•Endosteal layer
•sends septa to cranium.
•Firmly attached to sutures, base of skull, foramen
magnum.
•
As the age advances, it becomes thick & adheres mor e
•
As the age advances, it becomes thick & adheres mor e firmly to cranium
•Continuous with pericranium & orbital periosteum
•Dura of optic nerve is continuous with sclera

4. Endosteal
layer

5. •Meningeal layer •Provides sheath to cranial nerves
•Fuses with the epineurium
•Divides cranial cavity into spaces in which differe nt parts
of brain are lodged

6. Falxcerebri
•Between 2 cerebral hemispheres in the sagittalfissu re
•Ant
-Cristagalli
•Post-
Tentoriumcerebelli(contains straight sinus)
Intoccipital protuberance
•Sup.-
Sup sagittalsinus
Attached on either side of midline
Sup. Sag.sinus
Attached on either side of midline •Inf-
infsagittalsinus
Inf.sag.sinus

8. TentoriumCerebelli
•Tent like fold
•Below occipital lobes of cerebrum, covers sup surfa ce of
cerebellum
•Bet. Ant. Free margin & dorsum cellae is a large hi atus -
Tentorialincisure.
Occupied by midbrain
•
Attachments
•
Attachments
1) Outer convex margin- Transverse sulcus of occipi tal
bones-T. sinus
2) Lat- Sup margin of Petrosal bone-Sup petrosal sinu s
3) Forms trigeminal cave at the apex of petrosalbo ne
4) Ant-Ant & post clenoidprocess,

9. Cristagalli
Ant.clenoid
Post.clenoid Post.clenoid
Petrous
temporal
Transverse
Occipital
sulcus

10. Tentorial
incisure
Tentorium
cerebelli

11. Falxcerebelli
•Below tentorium,inpost cerebellarnotch
•Attachments-
1) Base-Tentoriumcerebelli
2) Post-intoccipital crest(Occ.Sinus )
3) Apex –passes at the sides of Fo.
magnum
Occipital sinus

12. DiphragmaSellae
•Forms roof of sellaturcica
•Blood supply-
1)Meningealbrof ant & post
ethmoidal
2) Intcarotid
3) Maxillary 3) Maxillary 4) Lacrimal
5) Vertebral
6) Occipital
7) Ascending pharyngeal

13. •Venous drain-
Meningeal
•Nerve supply-
Trigeminal / Vagus/ Hypoglosal/
Facial/ Glossopharyngeal

14. Spinal Dura Mater
•Attachment
–1) Foramen magnum margin /
bodies of C3,C4
2) Blends with periosteum of coccyx
•Forms atlanto-occipital mem.
•The meningeal layer here becomes periosteum of
vertebral canal vertebral canal
•Hence bet. duramater & periosteum is epidural spac e
•So duramater forms a tubular sheath around spinal
cord & spinal nerves
•At cervical region-Thickest

16. ArachnoidMater
•Enters only longitudinal fissure
•Thin , transparent
•Thick & opaque at the base
•Fuses with adventitia of carotid, vertebral A.

17. PiaMater
•Delicate ,enters sulci. Between it & brain is
subpialspace containing blood vessels
Spinal Leptomeninges
•Spinal nerves are covered by arachnoid when
they leave vertebral column
•At foramen fuse with perineurium
•Piamater enters ant. fissure

18. Spaces
1) Extradural
-
Bet. Spinal duramater & periosteum.
Contains loose connective tissue, fat & venous plex us
Anesthetic fluid can reach uptocranial base
2) Subdural-
Dura & arachnoid. Accidental injections can
cause injury to cord
3)
Subarachnoid
-
Arachnoid
&
pia
–
Contains CSF/ larger
3)
Subarachnoid
-
Arachnoid
&
pia
–
Contains CSF/ larger
arteries & veins

21. Subarachnoid Cisterns
•Gap bet. Pia& arachnoid
•Communicate with general subarachnoid
Cerebello Medullary
/
Pontine Inter
peduncular
Lat fossaCistern of
Great
Medullary
/
Cistern
magna
peduncular
Great cerebral vein
/Cistern
Ambiens/
Sup.cistern

23. •ArachnoidVilli-
Extentionof arachnoidmater &
space into sinuses(especially sup.sagittal)
•Arachnoidgranulations-
highly folded arachnoid
,Produce pitting on inner surface of calvaria

24. Cerebro-spinal fluid
•Clear fluid in subarachnoid space
•Brain floats in it
•Formation-Choroid plexus-50-70%
•Rest-Blood vessels
•
Circulation
-
•
Circulation
-
Lateral ventricle
3
rd
ventricle
Foramen of Monro
Cerebral auqeduct

26. 4
th
ventricle
Subarachnoid space
Foramen of Megendie/Luska
Re absorption in veins via
arachnoid
granulations
Re absorption in veins via
arachnoid
granulations
Amount produced-
500ml/day
Brain capacity-
135-150 ml
Contents-
1) Glucose
2) Proteins
3) RBCs
4) WBCs

28. Functions Of CSF
•Wt. reduction –Brain actual wt.-1400 gm
In CSF-25 gm
•Protection
Applied
-
1) Meningitis
Applied
-
1) Meningitis 2) Lumbar puncture