Transcript The Meninges and Blood Vessels of Brain and Spinal Cord, and the

The Meninges and Blood Vessels of
Brain and Spinal Cord,
and the Cerebrospinal Fluid
The Meninges of Brain and Spinal Cord
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The spinal cord and brain are
surrounded by three membranes,
the meninges. Named from the
outside inward they are the dura
mater, arachnoid, and pia mater.
The meninges of spinal cord
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Spinal dura mater
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Spinal arachnoid mater
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Spinal pia mater
Spinal dura mater
Characters
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Above, attached to
circumference of foramen
magnum
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Below, becomes thinner at
level of S2, invests filum
terminale to attach at back
of coccyx
Epidural space
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Position: lies between spinal dura mater and periosteum of vertebral canal
Contents: a quantity of loose connective tissue, fat, lymphatic vessels and
vertebral venous plexus, the spinal nerves on each side pass through the
epidural space which is applicable for block anesthesia
Subdural space
Spinal arachnoid mater
Characters
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A thin, delicate, tubular
membrane loosely
investing spinal cord
Above, it is continuous with
cerebral arachnoid mater
Subarachnoid space
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Position: lies between pia
and arachnoid maters
containing cerebrospinal
fluid
Terminal cistern : the
largest part of subarachnoid
space extending from
termination of spinal cord to
level of S2, where it is
occupied by nerves of
cauda equina, so it is the
best site for a lumbar
puncture
Lumbar spinal puncture (spinal tap)
Spinal pia mater
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A delicate vascular membrane
that closely invests the spinal
cord
Denticulate ligament: consist
of 21 pairs triangular
ligaments extending from
spinal cord on each side
between anterior and posterior
roots of spinal nerves to
spinal dura mate; these
ligaments help to fix position
of spinal cord.
Filum terminale: an extension
of pia beyond conus
medullaris
The Meninges of Brain
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Cerebral dural mater
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Cerebral arachnoid mater
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Cerebral pia mater
Cerebral dural mater
Characters
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A thick and dense
inelastic membrane that
composed of two layers,
an inner or meningeal
and outer or endosteal
It is in loose contact with
calvaria, and most
strongly adherent to
base of skull
Four septa
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Cerebral falx
Tentorium of cerebellum－in front there is a gap, the
tentorial incisure , for passage of midbrain
Cerebellar falx
Diaphragma sellae
Sinuses of duramater
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Superior sagittal sinus
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Inferior sagittal sinus
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Straight sinus
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Confluence of sinus
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Transverse sinus
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Sigmoid sinus
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Superior petrosal
sinuses
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inferior petrosal
sinuses
Cavernous sinus
 Position: lies on each side of sella turcica
 Relations of cavernous sinus:
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Internal carotid artery and abducent nerve run through the sinus
Oculomotor and trochlear nerves and ophthalmic and maxillary
divisions of trigeminal nerve lie in the lateral wall of the sinus
Cavernous sinus nerves
The flowing of the blood in dural sinus
Sup. sagittal sinus
Inf. sagittal sinus
Straight sinus
Confluence of sinus
Transverse sinus
Sup. petrosal sinus
Sigmoid sinus
Cavernous sinus
Inf. petrosal sinus
Internal jugular vein
Cerebral arachnoid mater
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Characters: a delicate
membrane covering
brain loosely, passing
over sulci and entering
only cerebral
longitudinal and
transverse fissures
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Arachnoid granulations － project into sinuses of dura mater,
serve as sites where cerebrospinal fluid diffuses into bloodstream
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Subarachnoid cisterns
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Cerebellomedullary
cistern
Interpeduncular cistern
Pontine cistern
Superior cistern
Cerebellomedullary cistern
Cerebral pia mater
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Closely invests brain
surface, in some areas the
pia invaginates into
ventricles to take part in
the formation of choroids
plexus
Circulation of cerebrospinal fluid (CSF)
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Cerebrospinal fluid is a
clear colorless fluid, which
acts as a transport medium
for nutrients and vaster
products and provides a
protective fluid cushion for
the central nervous system.
Production: produced by the
choroids plexuses within the
lateral, third and fourth
ventricles
Circulation of cerebrospinal fluid
CSF drains from lateral ventricle
mesencephalic aqueduct
interventricular foramina
fourth ventricle
third ventricle
median and two lateral apertures
subarachnoid space arachnoid granulations superior sagittal sinus
vein
Blood vessels of brain and spinal cord
Arteries of brain
Two sources
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Internal carotid
artery: supplies
anterior 2/3 of cerebral
hemisphere and parts
of diencephalon
Vertebral artery:
supplies postterior 1/3
of cerebral
hemisphere and parts
of diencephalon, brain
stem and cerebellum
Internal carotid artery
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Hypophysial a.
Ophtalmic a.
Anterior cerebral artery
Middle cerebral artery
Anterior choroidal artery
Posterior communicating
artery
Anterior cerebral artery
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Joined the fellow of the
opposite side by the
anterior communicating
artery
Cortical branches: supply
all medial surface of the
cerebral cortex as far back
as the parietooccipital sulcus
and superior border of the
suprolateral surface of the
cerebral hemisphere
Central branches: supply
caudate nucleus, anterior
part of lentiform nucleus and
anterior limb of internal
capsule
Middle cerebral artery
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Cortical branches:
supply most of
superolateral surface of
cerebral hemisphere and
insular lobe
Central branches:
supply lentiform and
caudate nuclei, genu and
posterior limb of internal
capsule (lenticulostriate
artery)
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Anterior choroidal artery:
passes backward, enters
inferior horn of lateral ventricle,
and ends in choroid plexus. It
supplies lateral geniculate
body, posterior limb of internal
capsule, middle 3/5 of crus
cerebri,and globus pallidus
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Posterior communicating artery:
runs backward to join posterior
cerebral artery
Vertebral artery
Cranial branche
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Anterior and posterior spinal
arteries
Posterior inferior cerebellar
artery
Branches of basilar artery
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Anterior inferior cerebral artery
Labyrinthine artery
Pontine arteries
Superior cerebellar artery
Posterior cerebral artery
Blood Supply to the Brain Stem
The brain stem (medulla, pons
midbrain) receives the bulk of its
blood supply from the
vertebrobasilar system. Except
for the labyrynthine branch,
all other branches supply the
brain stem and cerebellum
The posterior cerebral has only
a small contribution, its main
target being the posterior
cerebral hemispheres
Branches of the Basilar Artery
1. Anterior Inferior Cerebellar Arteries
(AICA), originates near the lower border
of the Pons just past the union of the
vertebral arteries.
Distribution:
a. supplies anterior inferior surface and
underlying white matter of cerebellum
b. contributes to supply of central
cerebellar nuclei
c. also contributes to upper medulla
and lower pontine areas
Branches of the Basilar Artery
2. Pontine arteries, numerous smaller
branches that can be subdivided into
Paramedian and Circumferential pontine
arteries. The Circumferential can be
further subdivided into Long and Short
pontine arteries.
Distribution:
a. paramedian pontine - basal pons
b. circumferential pontine - lateral pons
and middle cerebellar peduncle, floor
of fourth ventricle and pontine tegmentum
Branches of the Basilar Artery
3. Superior Cerebellar arteries, originates
near the end of the Basilar artery,
close to the Pons-Midbrain junction.
Runs along dorsal surface of cerebellum
Distribution:
a. cerebellar cortex, white matter and
central nuclei
b. Additional contribution to rostral
pontine tegmentum, superior cerebellar
peduncle and inferior colliculus
Branches of the Basilar Artery
4. Posterior cerebral arteries, the terminal
branches of the Basilar artery. They
appear as a bifurcation of the Basilar,
just past the Superior Cerebellar arteries
and the oculomotor nerve.
Curves around the midbrain and reaches
the medial surface of the cerebral
hemisphere beneath the splenium of the
corpus callosum
Distribution:
a. mainly neocortex and diencephalon
b. some contribution to interpeduncular
plexus
Branches of the Basilar Artery
5. Labyrynthine arteries, may branch
from the basilar, but variable in its
origin. Supplies the region of the inner
ear
Posterior cerebral artery
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Cortical branches:
supply medial and
inferior surfaces of
temporal lobe and
occipital lobe
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Central branches:
supply dorsal thalamus,
medial and lateral
geniculate bodies,
hypothalamus and
subthalamus
Cerebral arterial circle ( circle of Willis )
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Formation: formed by
anterior communicating
artery, both anterior
cerebral arteries, internal
carotid arteries, posterior
communicating arteries,
and posterior cerebral
arteries
Position: lies on sella
turcica around optic
chiasma, tuber cinereum
and mamillary bodies
Area of oxygendeprives brain
Blockage
Thrombus
Plaque
Microaneurysm
Lenticulostriate arteries
Subarachnoid hemorrhage
Intracerebral
hemorhage
Arteriovenous
malformation
Classification of cerebral vein
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Superficial cerebral veins
Superior cerebral veins
 Inferior cerebral veins
 Superficial middle cerebral veins
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Deep cerebral veins
Internal cerebral vein
 Basal vein (Rosenthal)
 Great cerebral vein (Of Galen)
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Veins of brain
Superficial cerebral veins
 Drain blood from cortex
and subcortical
medullary substance and
empty into adjacent
sinuses of dura mater
Veins of brain
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Deep cerebral veins:
drain deeper parts of
hemispheres, basal
nuclei, internal capsule,
diencephalon and
choroid plexus,
ultimately form great
cerebral vein which
enter straight sinus