Anatomy of meninges, ventricles, cerebrospinal fluid
1. MENINGES, VENTRICLES, CEREBROS
PINAL FLUID AND BOOLD SUPPLY
OF THE BRAIN
Dr. Israa M. Sulaiman
Dr. Mohammed Faez
Department of Anatomy
IMS/MSU
2. OBJECTIVES
• Illustrate and describe the Meninges’s three
membranes.
• Describe the structure of the meninges, its
blood supply and nerve supply.
• Illustrate and describe the venous blood
sinuses
3. The Meninges
• The Meninges are the
membrane covering the
brain and spinal cord.
• The Meninges consist of
three membranes:
1. The dura mater,
2. The arachnoid mater,
3. The pia mater.
5. The Meninges
1. Dura mater - • 2. Arachnoid -
strong, "Tough mother" spidery, holds blood
a. Falx cerebri vessels
b. Falx cerebelli
c. Tentorium cerebelli • 3. Pia mater -
d. Diaphragma sella "delicate mother"
8. 1) Falx cerebri
2) Tentorium
cerebelli
Superior view showing the duramater
9. DURA MATER
Thick dense inelastic membrane
and the outermost layer of the
meninges
Bilaminar:
Endosteal layer (outer)
Meningeal layer (inner)
These are closely united except
along certain lines, where they
separate to form venous sinuses.
10. DURA MATER
Endosteal layer ;
o Periosteum - inner surface of the
skull bones
o Not continuous with dura mater
of spinal cord
Meningeal layer ;
o Dura mater proper
o Covering the brain
o Continuous with dura mater of
spinal cord
o Folded inwards as 4 septa
between part of the brain
o The function of these septa is to
restrict the rotatory displacement
of the brain.
12. Superior sagittal sinus
Dura mater
(Dural venous sinus)
Endosteal layer
Meningeal layer
They are closely
united except along
certain lines; they
are separated to
form venous
sinuses
Subdural space
Coronal section of the upper part of the head
13. DURA MATER
Dura mater septa:
1. Falx cerebri
2. Falx cerebelli
3. Tentorium cerebelli
4. Diaphragma sella
15. The Falx Cerebri
• It is a sickle-shaped fold of dura
mater that lies in the midline
between the two cerebral
hemispheres.
• Its narrow end in front is attached to
the internal frontal crest and the
crista galli.
• Its broad posterior part blends in the
midline with the upper surface of the
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.
17. The Tentorium Cerebelli
• The tentorium cerebelli
is a crescent-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.
19. The Falx Cerebelli
• 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.
20. The Diaphragma Sellae
• The diaphragma sellae
is a small circular fold of
dura mater that forms
the roof for the sella
turcica.
• A small opening in its
center allows passage
of the stalk of the
pituitary gland
21. 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.
22. Dural Blood Supply
Dural Arterial Supply Dural Venous Drainage
• The dura mater’s arteries • The meningeal veins lie in
supply from the internal the endosteal layer of dura.
carotid, maxillary, ascending • The middle meningeal vein
pharyngeal, occipital, and follows the branches of the
vertebral arteries. middle meningeal artery
• From a clinical and drains into the
standpoint, the most pterygoid venous plexus or
important is the middle the sphenoparietal sinus.
meningeal artery, which is • The veins lie lateral to the
commonly damaged in head arteries.
injuries.
23. Arachnoid Mater
Delicate, impermeable &
avascular membrane covering the
brain
Lying between Pia mater
(internally) & dura
Mater(externally)
Separated from dura mater by a
potential space, the subdural
space (filled by a film of fluid)
Separated from pia mater by the
subarachnoid space (filled with
CSF)
The outer and inner surfaces
covered with flattened
mesothelial cells
25. Arachnoid mater
Arachnoid projects into venous
sinuses
- sites for CSF diffuses into
bloodstream
Arachnoid
granulations
Arachnoid mater Arachnoid villi
Subarachnoid space Subdural space
26. SUBDURAL SPACE :
• Superior cerebral Superior cerebral veins
beneath arachnoid
veins, traverse the
subdural space to reach
the superior sagittal
sinus and its lacunae
28. Subarachnoid Space (SP) :
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
The cisterna cerebellomedularis lies between inferior
surface of the cerebellum and roof of 4th ventricle
The cisterna interpeduncularis lies between 2 cerebral
hemispheres. All the cisternae are in free
communication with one another & with the
remainder of subarachnoid space
29. Superior
cistern
Chiasmatic
cistern
Interpeduncular
cistern
Pontine Cerebellomedullary cistern
cistern
Median sagittal section to show the subarachnoid cisterns &
circulation of CSF
30. Pia mater
Arachnoid
Dura
*
Subarachnoid haemorrage
31. Pia Mater
• Pia Mater is a vascular
membrane covered by
mesothelial cells.
• Closely invests the
brain, covering the
gyri, descending into
the deepest sulci &
closely applied to the
cortical surface.
33. Pia Mater
It extends out over the cranial nerves & fuses
with their epineurium
The cerebral arteries entering the substance of
the brain, carry a sheath of pia mater with them
The pia mater forms the TELA CHOROIDAE .
The tela choroidae fuse with ependyma to form
the choroid plexus
Choroid plexus forms CSF
34. Choroid plexus of
lateral ventricle
Ependyma
Pia mater of
tela choroidae
Choroid plexus
of 3rd ventricle
Coronal section of the interventricular foramen showing the choroid
plexus of 3rd & lateral ventricles
37. OBJECTIVES
• Illustrate and describe the ventricles.
• Describe the structure of the ventricles.
• Illustrate and describe the cerebrospinal
fluid (CSF) formation, absorption and
circulation.
38. VENTRICLES(Ventricular System)
• A ventricle is an internal
cavity of the brain. Within
the brain, which is filled
with cerebrospinal
fluid(CSF).
• The ventricular system is
composed of two lateral
ventricles and two midline
ventricles( third and fourth
ventricles).
39. VENTRICLES(Ventricular System)
• The chambers are
connected to allow the flow
of cerebrospinal fluid via
two interventricular
foramen (referred to as the
foramen of Monro) and the
cerebral aqueduct (referred
to as the aqueduct of
Sylvius).
40. Lateral ventricle
Interventricular
foramen (Monro)
Cerebral
aqueduct
Fourth ventricle
Third ventricle
Central canal of
medulla
oblongata &
spinal cord
Lateral view to show the ventricular system of the CNS
44. Lateral Ventricles
• The lateral ventricles
are two curved shaped
cavities located within
the cerebrum.
• The lateral ventricles
are separated by the
septum pellucidum and
do not communicate
directly
46. Lateral ventricle
C-shaped cavity & may be divided into :
1. Body
2. Anterior
3. Posterior
horn Third
horn
ventricle
4. Inferior
horn
Fourth
ventricle
Lateral view of the ventricular cavities of the brain
47. Posterior horn
Anterior horn
Inferior horn
Lateral view to show the ventricular system of the CNS
48. Third ventricle
The third ventricle is a narrow cavity or a slitlike cleft between the 2
thalamus
Communicates ;
• Anteriorly with lateral ventricles through interventricular foramina
(of monro)
• Posteriorly with fourth ventricle through cerebral aqueduct (of
sylvius)
Posterior view to show the ventricular system of the CNS
50. Third ventricle
ROOF
Body of fornix
Lateral wall
Thalamus
Third
ventricle
FLOOR
Hypothalamus
Coronal section of the brain (posterior view)
51. Fourth ventricle
• The fourth ventricle Is a
rhomboid or diamond
shaped cavity.
• It is a wide and
flattened space located
just anterior to the
cerebellum and
posterior to the
upper, or superior, half
of the medulla
oblongata and the pons.
52. Fourth ventricle
Fourth
ventricle
Cerebral
aqueduct
POSTERIOR
ANTERIOR
Cerebellum
Pons
Medulla
oblongata
(superior
half) Central
canal
(spinal
Sagittal section of the 4th ventricle cord)
54. Roof or posterior wall of fourth
ventricle :
Superior part of the roof ;
Superior medullary velum
Cerebral
aqueduct
ANTERIOR
POSTERIOR
Pons
Medulla
oblongata
(superior
half)
Inferior part of the roof ;
Inferior medullary velum
Fig. : Sagittal section of the 4th ventricle
55. Floor or rhomboid fossa of fourth ventricle :
Medial
sulcus
Formed by ; (divides the floor
into symmetrical
halves)
1. Posterior
surface of the
pons Medial
eminence
2. Cranial ½
Sulcus
of the
limitans
medulla
oblongata
Facial
colliculus
Stria
Posterior view of the medullaris
4th ventricle Vagal Hypoglossal (strands of nerve
triangle triangle fibers)
56. CENTRAL CANAL
Opens superiorly into the fourth ventricle
Fourth
ventricle
Extends ;
Inferior ½ of
medulla
oblongata
Central canal
Entire (Lined with
length of ependyma but no
spinal cord choroid plexus in the
central canal)
60. CHOROID PLEXUS
• It is formed by invaginating
of vascular pia mater into the Lateral ventricle
ventricular cavity
• It becomes highly convoluted
& produce a spongy-like
appearance
• It enters the 3rd and 4th
ventricles through their
roofs, and the lateral
ventricles through the
choroid fissure Third ventricle
• produces cerebrospinal fluid
Fourth
(CSF) ventricle
61. Pia Mater Choroid
BODY OF Plexus of
Cavity Of FORNIX The Lateral
Lateral Ventricle
Ventricle
CORPUS
CALLOSUM
CN
Pia Mater of
Ependyma Tela
THALAMUS Choroidae
Cavity Of Choroid
Third Plexus of
Ventricle The Third
Ventricle
Blood supply derives from choroidal branches of the internal carotid & basilar
arteries
Coronal section of the cavities of the lateral and 3rd ventricles
62. Arachnoid mater
Pia mater
Ependyma
Cavity of fourth ventricle
CEREBELLUM
Choroid plexus of the
fourth ventricle
•T shaped, vertical part is double
• Horizontal part extends into lateral recesses of each ventricle (foramina of Luskha)
• Blood supply ; posterior inferior cerebellar arteries
63. What is cerebrospinal fluid (CSF) ?
• Clear, colorless fluid
• Produced by the choroid plexus
• Found in the :
Ventricles of the brain
Subarachnoid space (between Arachnoid + Pia mater) around the brain
& spinal cord
• The pressure of the CSF is kept remarkably constant.
• Based on the Monro-Kellie doctrine :
• “Volume of BLOOD, CSF & BRAIN at any time must be
relatively constant”
64. Physical characteristics and composition of
the CSF
Appearance Clear and colourless
Volume 130 ml
Rate of production 0.5 ml/min
Pressure 60-150 mm of water
Composition
protein 15-45 mg/100 ml
glucose 50-85 mg/ 100 ml
chloride 720-750 mg/100 ml
No. of cells 0-3 lymphocytes/cu mm
65. Function of the CSF :
1. Cushions & protects the CNS from trauma
2. Provides mechanical buoyancy & support for the brain
3. Serves as a reservoir & assists in the regulation of the
contents of the skull
4. Nourishes the CNS
5. Removes metabolites from the CNS
6. Serves as a pathway for pineal secretions to reach the
pituitary gland
66. Sites of formation :
1. Choroid plexus of the ventricle cavities, mostly is formed
in the LATERAL VENTRICLES
2. Some originate from the ependymal cells lining the
ventricles
3. Some from the brain substances through perivascular
spaces
Movement of CSF inside the ventricle is controlled
by the:
1. Pulsation of the artery in the choroid plexus
2. By the aid of the cilia & microvilli of the ependymal
cells
67. 5
Superiorly =
lateral aspect of Choroid plexus of
each cerebral 1 the lateral ventricle
hemisphere 2
3
Choroid plexus of 3.2
the 3rd ventricle
3.1 Choroid plexus of
the 4th ventricle
Inferiorly =
subarachnoid 4
space around the
brain & spinal
cord
68. cerebrospinal fluid (CSF)
• The CSF is formed in the lateral
ventricles escapes by the foramen of
monro into the third ventricle
• From the third ventricle by the
aqueduct into the fourth ventricle.
• Then from the fourth ventricle the
fluid is poured into the subarachnoid
spaces through the medial foramen
of majendie and the two lateral
foramina of luschka.
• There is no evidence that functional
communications between the
cerebral ventricles and the
subarachnoid spaces exist in any
region except from the fourth
ventricle.
69. Site of formation
Choroid plexus of the
lateral ventricle
1. Lateral ventricle
Superiorly Interventricular foramina Superiorly
2. Third ventricle
Cerebral aqueduct Absorbed
Absorbed
3. Fourth ventricle
3.2 Lateral 3.2 Lateral
foramina foramina
(Luschka) (Luschka)
3.1 Median
foramen
(Magendie)
4. Subarachnoid space
Inferiorly
70. Circulation of CSF in subarachnoid space :
Superior
cistern
Chiasmatic
cistern
Median
Interpeduncular foramen of
cistern 4th ventricle
Pontine Cerebellomedullary cistern
cistern
Median sagittal section to show the subarachnoid cisterns &
circulation of CSF
71. Factors that facilitate the flow of CSF in
subarachnoid space ;
1. Pulsation of the cerebral & spinal arteries
2. Movements of the vertebral column
3. Respiration & coughing
4. Changing of the positions
72. Absorption of CSF into dural venous sinuses
• Main sites - arachnoid villi
(project into dural venous
sinuses, especially, superior
sagittal sinus)
• Arachnoid villi are covered by
endothelium of the venous
sinus
• Arachnoid villi tend to be
grouped together & form
elevations known as arachnoid
granulations
• CSF pressure >> the pressure
in the sinus
• The rate of absorption of CSF
through the arachnoid villi
controls the CSF pressure
73.
74.
75. CLINICAL APPLICATION
Hydrocephalus
• The term hydrocephalus is
derived from the Greek
words "hydro" meaning
water and "cephalus"
meaning head.
• It is excessive accumulation
of fluid in the brain.
78. OBJECTIVES
• Illustrate and describe the formation of the
circle of willis
• Describe the blood supply of the brain
– Arterial supply
– Venous drainage
79. Blood Supply of The Brain
• The brain receives it
arterial supply from two
pairs of vessels, the
vertebral and internal
carotid arteries which
are interconnected in
the cranial cavity to
produce an arterial
circle (of Willis).
81. Internal Carotid Artery
• Begins – bifurcation of Com Carotid A
• Perforates base of skull – carotid canal
• Enters middle cranial fossa beside dorsum sellae
• In the cavernous sinus
– Horizontal
• Emerge out – medial side of Ant clinoid process –
perforates dura & arachnoid mater – enters
subarachnoid space
• Turns posteriorly – below optic nerve
• Turns upward – lateral to optic chiasma
• Now is under anterior perforated susbtance
• Divides – into ANTERIOR & MIDDLE cerebral arteries
82. Middle cerebral
Posterior artery
Anterior cerebral
communicating
artery
artery
Internal carotid artery
in cavernous sinus
Posterior cerebral
artery
Internal carotid artery
Basilar artery In temporal bone
External carotid artery
Vertebral artery
Common carotid artery
83. Vertebral Artery
• Branch of first part of subclavian A
• Passes – foramen transvesarium C6 – C1
• Enters through foramen magnum – perforates
dura & arachnoid mater – enters subarachnoid
space
• Turns upward, forward, medially – medulla
oblongata
• Lower border of pons – joins opposite side
– BASILAR artery
84. Middle cerebral
Posterior artery
Anterior cerebral
communicating
artery
artery
Internal carotid artery
in cavernous sinus
Posterior cerebral
artery
Internal carotid artery
Basilar artery In temporal bone
External carotid artery
Vertebral artery
Common carotid artery
85. Blood Supply of The Brain
• VERTEBRAL • INTERNAL CAROTID
– Basilar – Middle cerebral
– Posterior cerebral artery – Anterior cerebral
– Anterior communicating
artery
– Posterior
communicating artery
CIRCLE OF WILLIS
86. Branches of :-
• VERTEBRAL • INTERNAL CAROTID
– Basilar – ACA
– PCA – MCA
– Pontine – Ophthalmic
– Labyrinthine – Ant ComA
– Ant Inf CA – Post Com A
– Sup cerebellar – Choroidal
– Choroidal
87. • CEREBRAL (ICA) • CRANIAL (VERT)
– Ophthalmic – Meningeal
– Post Communicating – Post Spinal
– Choroidal – Ant Spinal
– Ant Cerebral – Post Inf Cerebellar
• Cortical – Medullary
• Central
• (BASILAR)
• Communicates with
– Ant Comm Art
– Pontine
– Post Cerebral – Labyrinthine
– Mid Cerebral – Ant Inf Cerebellar
• Cortical – Sup Cerebellar
• Central – Post Cerebral
• Cortical
• Central
• Choroidal
88. Circle of Willis
• Interpeduncular fossa –
base of brain
• Anastomosis
– 2 internal carotid
arteries
– 2 vertebral arteries
• In the subarachnoid
space
98. MIDDLE CEREBRAL ARTERY
LOBE AREA
FRONTAL Motor – except for paracentral lobule
Motor speech – esp left side
PARIETAL Sensory – except for paracentral lobule
Sensory speech
TEMPORAL Auditory
104. ARTERIES to specific brain areas
Corpus striatum Middle & lateral Anterior &
striate Middle cerebral
Internal capsule artery
Thalamus PComA, basilar, PCA
Midbrain PCA, supCerebellarA, basilar
Pons Basilar, Ant, inf, supCerebellarA,
Medulla Vertebral, ASA,PSA,PICA, basilar
oblongata
Cerebellum supCerebellar, AICA,PICA
105. VENOUS DRAINAGE of THE BRAIN
• EXTERNAL • INTERNAL • SPECIFIC
– Superior – Thalamo – Midbrain
– Pons
cerebral striate – Medulla
– Superficial oblongata
middle – choroidal – cerebellum
cerebral
– Deep middle
cerebral
106. Superior cerebral
Superior
Sagittal
sinus
Superior
Superficial Sagittal
sinus Internal
Middle
cerebral
cerebral
Transverse Great
sinus cerebral
Straight
sinus
Inferior
Sagittal
sinus Occipital
sinus
basal
107. Superior Superior anastomotic V Superior cerebral
Sagittal
sinus
Inferior anastomotic V
Superficial
Middle cerebral
Transverse
sinus
108. Superior
Sagittal Inferior
sinus Sagittal
sinus
Internal
cerebral
Great
cerebral
Straight
sinus
Site of
junction
with
transverse
sinus
Occipital
sinus
basal
109.
110. EXTERNAL CEREBRAL VEIN
VEIN AREA DRAINS INTO
Superior Superior sagittal
cerebral Lateral surface of sinus
Superficial cerebral Cavernous sinus
middle hemisphere
cerebral
Deep middle Insula Joined by ant
cerebral cerebral & striate-
basal vein
Sup anas V Superior sagittal sinus
Inf anas V Inferior sagittal sinus
111. INTERNAL CEREBRAL VEIN
VEIN AREA DRAINS INTO
Thalamostriate Basal ganglia, Internal cerebral
thalamus, vein - great
Choroidal internal cerebral vein –
capsule,Tela straight sinus
choroidae of 3rd
ventricle,hippo DURAL VENOUS
campus SINUS
112. VEIN of specific areas
Midbrain Basal, great cerebral
Pons Basal, cerebellar
Medulla oblongata Anterior & posterior spinal
Cerebellum Great cerebral
113. Great
cerebral
Superior cerebral vein vein
Superior sagittal sinus Straight
sinus
Inferior sagittal sinus
Middle cerebral vein
Medial aspect of
Confluence of
hemisphere
Cavernous sinus sinus
Superior
Inferior petrosal
petrosal sinus
sinus Transverse sinus
(R & L)
IntJugular IntJugular
vein vein
Sigmoid sinus
(R & L)
114. Inferior sagittal Superior sagittal sinus Falx cerebri
sinus
Tentorium
cerebelli
Superior
petrosal
sinus
*
Confluence of
sinus
Straight
Inferior sinus
Sigmoid Transverse
petrosal
sinus sinus
sinus
116. Cavernous sinus
• Lateral to body of sphenoid bone
• Connected to opposite – intercavernous S
• Receives blood
– Middle cerebral V
• Drains into
– Int Jugular V –via Inf petrosal sinus
– Transverse S – via Sup petrosal S
• Dural Venous sinuses – emissary veins – extracranial V
117. CLINICAL APPLICATION
• Stroke or cerebrovascular accident:-
– Blockage in the artery – cerebral infarction
• Carotid artery
• Basilar artery
– Bleeding within the brain – intracerebral
haemorrhage
• Aneurysm
• Subarachnoid haemorrhage
• Intracerebral haemorrhage - hypertension
– Damages one side of the body - contralateral