Cranial meninges

1. CRANIAL MENINGES
Rajasri Manimaran
Group 2

2. Protection of the Brain
• The Skull
• Cranial meninges
• Cerebrospinal fluid
• Blood brain barrier

3. THE MENINGES

4. 1. Dura Mater - Composed of two layers:
a) Periosteal – outer layer, attaches to
bone.
b) Meningeal – inner layer, closer to brain.
Cranial Meninges - 3 layer protective membrane
Two layers fused, except to enclose the dural sinuses
3. Pia Mater - delicate, follows convolutions.
2. Arachnoid Layer - ‘spider’ web like.

5. Coronal section of the upper part of the head
Endosteal
layer
Meningeal
layer
They are closely
united except
along certain
lines; they are
separated to
form venous
sinuses
Superior sagittal sinus
(Dural venous sinus)
Dura mater
Subdural
space

6. Sagittal section showing the duramater
1) Falx cerebri
2) Tentorium
cerebelli
3) Falx
cerebelli
4) Diaphragma sellae

8. DURAL NERVE SUPPLY
 Branches of the trigeminal, vagus, and
first three cervical nerves and branches
from the sympathetic system pass to the
dura.
 The dura is sensitive to stretching, which
produces the sensation of headache.

9. DURAL BLOOD SUPPLY
 The middle meningeal artery supplies
most of the blood for the dura mater,
though the meningeal branches of
the posterior and anterior ethmoidal
artery also contribute.

10. ARACHNOID MATER

11. Subdural space
Potential space between dura and arachnoid
mater.
Cranial Meningeal Spaces
Epidural space
Potential space superior to dura.
Subarachnoid space
Filled with CSF
Contains the blood vessels supplying brain.

13. SUBARACNOID SPACE
 Relatively narrow
over the surface of
cerebral
hemisphere, but
sometimes becomes
much wider in areas
at the base of the
brain, the widest
space is called
subarachnoid
cisterns.

14. Median sagittal section to show the subarachnoid cisterns
& circulation of CSF
Superior
cistern
Interpeduncular
cistern
Cerebellomedullary
cistern
Chiasmatic
cistern
Pontine
cistern

15. PIA MATER
 Pia mater functions to cover and protect
the central nervous system (CNS), to
protect the blood vessels and enclose the
venous sinuses near the CNS, to contain
the cerebrospinal fluid (CSF) and to form
partitions with the skull.
 The CSF, pia mater, and other layers of
the meninges work together as a
protection device for the brain, with the
CSF often referred to as the fourth
layer of the meninges.

17. PATHOLOGY
There are three types of hemorrhage involving the
meninges:
 An epidural hematoma arise after an accident or
spontaneously
 A subdural hematoma is a hematoma (collection
of blood) located in a separation of
the arachnoid from the dura mater. The small
veins that connect the dura mater and
the arachnoid are torn, usually during an
accident, and blood leaks into this area
 A subarachnoid hemorrhage is acute bleeding
under the arachnoid; it may occur spontaneously
or as a result of trauma.

18.  Other medical conditions that affect the
meninges include meningitis (usually
from fungal, bacterial, or viral infection)
and meningiomas that arise from the
meninges, or from meningeal
carcinomatoses (tumors) that form
elsewhere in the body and metastasize to
the meninges.

20. CRANIAL VENOUS SINUSES
 The dural venous sinuses (also
called dural sinuses, cerebral sinuses,
or cranial sinuses) are venous channels
found between layers of dura mater in
the brain.
 They receive blood from internal and
external veins of the brain,
receive cerebrospinal fluid (CSF) from
the subarachnoid space, and ultimately
empty into the internal jugular vein.

21. Name Drains to
Inferior sagittal sinus Straight sinus
Superior sagittal sinus
Typically becomes right transverse
sinus or confluence of sinuses
Straight sinus
Typically becomes left transverse sinus
or confluence of sinuses
Occipital sinus Confluence of sinuses
Confluence of sinuses Right and Left transverse sinuses
Sphenoparietal sinuses Cavernous sinuses
Cavernous sinuses Superior and inferior petrosal sinuses
Superior petrosal sinus Transverse sinuses
Transverse sinuses Sigmoid sinus
Inferior petrosal sinus Sigmoid sinus
Sigmoid sinuses Internal jugular vein

22. ARTERIES TO SPECIFIC BRAIN AREAS
Corpus striatum Middle & lateral
striate
Anterior &
Middle cerebral
arteryInternal capsule
Thalamus PComA, basilar, PCA
Midbrain PCA, supCerebellarA, basilar
Pons Basilar, Ant, inf, supCerebellarA,
Medulla
oblongata
Vertebral, ASA,PSA,PICA, basilar
Cerebellum supCerebellar, AICA,PICA

23. BLOOD SUPPLY OF THE BRAIN
 VERTEBRAL
 Basilar
 Posterior cerebral artery
 INTERNAL CAROTID
 Middle cerebral
 Anterior cerebral
 Anterior communicating
artery
 Posterior
communicating artery
CIRCLE OF WILLIS

25. Subarachnoid hemorrhage

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Aneurysm

29. SYMPTOMS
 Headache (sudden onset, greater
severity)
 Nausea and vomitting
 Loss or impairment of consciousness (may
progress to coma and death)
 Confusion and irritability
 Meningial irritation and nuchal rigidity
(stiff neck)
 Focal neurological deficits (may indicate
site of lesions).

30. DIFFERENTIAL DIAGNOSIS
 Meningitis
 Migraine
 Intracerebral hemorrhage
 Ischemic stroke

34. Grade Signs and symptoms Survival
1
Asymptomatic or minimal headache and
slight neck stiffness
70%
2
Moderate to severe headache; neck
stiffness; no neurologic deficit
except cranial nerve plasy
60%
3 Drowsy; minimal neurologic deficit 50%
4
Stuporous; moderate to severe
hemiparesis; possibly early decerebrate
rigidity and vegetative disturbances
20%
5 Deep coma; decerebrate rigidity; moribund 10%
Hunt and Hess classification

35. TREATMENT
 Stabilizing patient.
 Prevention of rebleeding by obliterating
the bleeding source.
 prevention of a phenomenon known
as vasospasm and,
 prevention and treatment of
complications.

36. PREVENTING RE-BLEEDING
 Up to 14% of SAH patients may
experience re-bleeding within 2 hours of
the initial hemorrhage
 Re-bleeding was more common in those
with a systolic blood pressure >160mm
Hg
 Anti-fibrinolytic therapy may reduce re-
bleeding but has not been shown to
improve outcomes
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Association.Allrights
reserved.

37. SURGICAL AND ENDOVASCULAR
MANAGEMENT OF SAH
 Surgery – clip aneurysm base
 Endovascular – coiling
 Should be performed within 2 days of
hemorrhage.
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reserved.

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Clipping

39. LEFT IMAGE ARROW -ANGIO WITH LARGE ANEURYSM
RIGHT IMAGE ARROW – ANGIO SHOWING ANEURYSM POST CLIPPING
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Angio Image Courtsey: The University of Texas Health Science Center at San Antonio – Department of Neurosurgery

40. SURGICAL AND ENDOVASCULAR
MANAGEMENT OF SAH
 Combined morbidity and mortality was
significantly greater in surgically treated
patients than in those treated with
endovascular techniques (30.9% vs. 23.5%;
absolute risk reduction 7.4%)
 During the short follow-up period, the re-
bleeding rate for coiling was 2.9% versus
0.9% for surgery
 There have been no randomized
comparisons of coiling versus clipping for
unruptured aneurysms
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reserved.

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Coiling

42. COIL SYSTEM EMBOLIZATION:
IMMEDIATE RESULT
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reserved.
Angio showing large ICA aneurysm
Same aneurysm - Post GDC Coiling
Angio Image Courtsey: The University of Texas Health Science Center at San Antonio – Department of Neurosurgery

44. PREVENTING VASOSPASM
 The use of calcium channel blockers,
thought to be able to prevent the spasm
of blood vessels by
preventing calcium from entering smooth
muscle cells, has been proposed for the
prevention of vasospasm.
 The oral calcium channel
blocker nimodipine improves outcome if
administered between the fourth and
twenty-first day after the hemorrhage.

45. PREVENTING OTHER COMPLICATIONS
 If medication don’t help,
then angiography may be attempted to
identify the sites of vasospasms and
administer vasodilator medication (drugs
that relax the blood vessel wall) directly
into the artery.
 Angioplasty (opening the constricted area
with a balloon) may also be performed.

46. SUMMARY AND CONCLUSIONS
 The current standard of practice calls
for microsurgical clipping or endovascular
coiling of the aneurysm neck whenever
possible
 Treatment morbidity is determined by
numerous factors, including patient,
aneurysm, and institutional factors
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Association.Allrights
reserved.

47. SUMMARY AND CONCLUSIONS
 Favorable outcomes are more likely in
institutions that treat high volumes of
patients with SAH, in institutions that offer
endovascular services, and in selected
patients whose aneurysms are coiled rather
than clipped
 Optimal treatment requires availability of
both experienced cerebrovascular surgeons
and endovascular surgeons working in a
collaborative effort to evaluate each case of
SAH
1/24/2015©2009,
AmericanHeart
Association.Allrights
reserved.