Dural folds dural venous sinuses.pdf

Anatomy

1. Dural folds and
duralvenous
sinuses
Dr. Mrs. R. Niranjan,
Senior lecturer,
Department of Anatomy
University of Jaffna
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Dr. Mrs. Romini Niranjan, University of
Jaffna
8/10/2022

2. Objectives
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To identify and describe-
Layers of dura mater
Folds of inner layer of
dura mater
Falx cerebri
Falx cerebelli
Tentorium cerebelli
Diaphragmasella
Dural venous sinuses
Superior sagittal sinus
Inferior sagittal sinus
Straight sinus
Transverse sinus
Sigmoid sinus
Superior and inferior petrosal
sinus
Cavernous sinus
Occipital sinus
Clinical anatomy of cavernous
sinus
Dr. Mrs. RominiNiranjan, University of Jaffna
8/10/2022

3. Dura mater
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Toughest and thickest
2 layers:
Endosteal/periosteal
and meningeal layers
2 layers are closely
arrangedexcept at
certain lines they
separate and forms
the duralvenous
sinuses
Cranial cavity are covered by outer
layer of duramater (endosteallayer
of dura)
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

4. Dural folds
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Meningeal layer
forms the folds-
1.Falx cerebri
2.Tentorium cerebelli
3.Falx cerebelli
4.Diaphragmasellae
Falx cerebri
It isa larger and
sickle shaped fold
ofmeningeal layer
ofdura mater
It lies vertically in
themidlinebetween
thecerebral
hemispheresof
thehuman brain
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

5. Falx cerebri
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Anterior –it is attaches to
thecrista galliand
internal frontal crest
Posterior -It is blends
with the upper surface of
thetentoriumcerebelli
Superior sagittal sinus
runs in itsupper fixed
margin.
Inferior sagittal sinus
runs in its lower concave
free margin
Straightsinus runs along
its attachment to
tentorium cerebelli
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

6. Tentorium cerebelli
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It is crescent-shaped
foldof dura mater
It forms the roof for
posterior cranial fossa
It covers the upper
surface of the
cerebellum and
supports the occipital
lobes of the cerebral
hemispheres.
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

7. Tentorium cerebelli
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A gap ( the tentorial notch ) is present in front for the
passage of the midbrain
It has an inner free border and outer attached border
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

8. Dural folds
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Falx cerebelli
It is asmall sickle-
shaped fold of dura
mater
It is attached to the
internal occipital
crest
Its posterior margin
contains the occipital
sinus
Diaphragmasellae
It is asmall circular
foldof dura mater that
forms theroof for sella
turcica
A small opening in its
center allows passage of
the stalk of the
hypophysiscerebri
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

9. Falxcerebelli
8/10/2022
Dr. Mrs. Romini Niranjan, University of Jaffna
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It is located below the tentorium
cerebelli
It extends into the space between the
two cerebellar hemisphere
It attached with occipital crest and the
posterior portion of the tentorium.

10. Venous Blood Sinuses
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They are blood-filled
spaces situated
between the layers of
the dura mater
They are lined by
endothelium
Their walls are thick
and composed of
fibrous tissue
They have no
muscular tissue
They have no valves
They receive
tributaries from the
brain, diploieveins
and face
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

11. Superior Sagittal Sinus
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It occupies the upper fixed
border of the falx cerebri.
It begins in the front at the
foramen cecum where it
receives a vein from the
nasal cavity
It runs backward and at the
internal occipital
protuberance it deviates to
one side (usually the right)
and becomes continuous
with the transverse sinus
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

12. Superior sagittal sinus
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It receives the superior
cerebral veins.
At the internal occipital
protuberance it is
dilated to form the
confluence of the
sinuseswhich is
connected to the opposite
transverse sinus and
receives the occipital
sinus.
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

13. Superior sagittal sinus
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Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

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Dr. Mrs. Romini Niranjan, University of Jaffna
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15. Inferior Sagittal Sinus
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It occupies the free lower
margin of the falxcerebri
It runs backward and joins
the great cerebral vein and
forms the straight sinus
Veins have no valves ; no
muscular tissue in their wall
and drain into venous
sinuses
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

16. Straight Sinus
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It occupies the line of
junction of the falx cerebri
with the tentorium cerebelli
It is formed by the union of
the inferior sagittal sinus
with the great cerebral vein.
It ends by turning to the left
( sometimes to the right ) to
form the transverse sinus.
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

17. Occipital Sinus
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It is a small sinus
occupying the attached
margin of the falx
cerebelli
It communicates with
the vertebral veins
Superiorly it drains
into the confluence of
sinuses.
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

18. Transverse Sinus
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They are paired and begin
at the internal occipital
protuberance
The right sinus usually
continuous with the
superior sagittal sinus
The left is continuous with
the straight sinus
They end by turning
downward as the sigmoid
sinuses.
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

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Dr. Mrs. Romini Niranjan, University of Jaffna
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Dr. Mrs. Romini Niranjan, University of Jaffna
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21. Superior and Inferior Petrosal
Sinuses
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They are small and situated
on the superior and
inferior borders of the
petrous part of the
temporal bone on each side.
Each superior sinus drains
the cavernous sinus into
the junction of transverse
and sigmoid sinus
Each inferior sinus drains
the cavernous sinus into
the internal jugular vein
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

22. Sigmoid Sinuses
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They are a direct
continuation of the
transverse sinuses
Each sinus turns downward
and medially and grooves
thetemporal bone.
Here it lies behind the
mastoid antrum.
It then turns downward
through the posterior part
of the jugular foramen to
become continuous with the
superior bulb of the
internal jugular vein
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

23. Cavernous Sinuses
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They are situated in the
middle cranial fossa on each
side of the body of the
sphenoid bone

Extension: from the
superior orbital fissure in
front to the apex of the
petrous part of the temporal
bone
The 3
rd
; 4
th
cranial nerves
and the ophthalmic
maxillary divisions of the
trigeminal nerve run forward
in its lateral wall of this
sinus.
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

24. Cavernous Sinuses
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They lie between the
periosteumof the
sphenoid and the inner
layer of the duramater
Contents: Internal
carotid artery, its
sympathetic nerve
plexus and abducent
nerve run forward
through it.
Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

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Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

26. Cavernous sinus
The tributaries are
1.Superior ophthalmic
vein
2.Inferior ophthalmic
vein
3.Cerebral veins
4.Central vein of the
retina
5.Sphenopareitalsinus
Cavernous sinus
thrombosis
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Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022

27. Cavernous sinus
Cavernous sinus drains posteriorly into the superior and
inferior petrosalsinuses and inferiorly into the pterygoid
venous plexus
Both sides –cavernous sinuses communicate with one
another by means of the anterior and posterior
intercavernoussinuses which run in the diaphragma
sellaein front and behind the stalk of the hypophysis
cerebri.
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Dr. Mrs. Romini Niranjan, University of Jaffna
8/10/2022
Cavernous sinus has communicating branches from the sinus of
the face
Particularly in the‘danger area’

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Dr. Mrs. Romini Niranjan, University of Jaffna
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Dr. Mrs. Romini Niranjan, University of Jaffna
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Thank you