Anatomy

2. DURAL VENOUS
SINUSES
Dr. Hafsa Nisar

3.  Blood from cerebral cortex empty
into adjacent sinuses of dura
mater

4. CEREBRAL DURA MATER
ENDOSTEAL
LAYER
MENINGEAL LAYER

6. TENTORIUM CEREBELLI

7. Dural Venous Sinuses
 Situated between the layers of
the dura mater .
 Dural sinuses are lined by
endothelium, and their walls
are thick but devoid of muscular
tissue. They have no valves.
 Function. to receive blood from
the brain through the cerebral
veins and the cerebrospinal fluid
from the subarachnoid space
through the arachnoid villi
 .

9.  The blood in the dural
sinuses ultimately drains
into the internal jugular
veins in the neck.
 Emissary veins, which
are also valveless,
connect the dural venous
sinuses with the diploic
veins of the skull and with
the veins of the scalp

10. Dural venous
sinuses
1) Superior sagittal sinus
2) Inferior sagittal sinus
3) Straight sinus
4) Transverse sinus
5) Sigmoid sinus
6) Occipital sinus
7) Superior petrosal sinus
8) Inferior petrosal sinus
9) Cavernous sinus

11. DURAL VENOUS SINUSES
PAIRED
CAVERNOUS
SUP. & INF.
PETROSAL
TRANSVERSE SIGMOID
UNPAIRED
SUP. & INF.
SAGITTAL
STRAIGHT OCCIPITAL

12. Venous sinuses

13. The superior sagittal sinus
 Occupies the
upper fixed border
of the falx cerebri

14.  It begins anteriorly at the foramen
cecum, where it occasionally
receives a vein from the nasal
cavity.
 It runs posteriorly, grooving the
vault of the skull.
 it deviates to one or the other
side (usually the right) at the
internal occipital protuberance
and becomes continuous with the
corresponding transverse sinus.

15. The superior sagittal sinus
The confluence of
the sinuses
 is formed at the
internal occipital
protuberance.
 sinus usually dilates
and becomes
continuous with the right
transverse sinus; it is
connected to the
opposite transverse

16.  Numerous arachnoid
villi and granulations
project into the
lacunae, which also
receive the diploic
and meningeal veins .
 The superior sagittal
sinus in its course
receives the superior
cerebral veins

18. 2. The inferior sagittal sinus
 occupies the free lower margin
of the falx cerebri.
 It runs backward and joins the
great cerebral vein at the free
margin of the tentorium
cerebelli to form the straight
sinus.

20. The inferior sagittal sinus receives a few cerebral veins
from the medial surface of the cerebral hemispheres.

21. The straight sinus
 It is formed by the union
of the inferior sagittal
sinus with the great
cerebral vein.
 occupies the line of
junction of the falx cerebri
with the tentorium
cerebelli.
 It ends by turning to the
left (sometimes to the
right) to form the

22. 1. The transverse sinuses
 are paired structures that begin at the internal
occipital protuberance
 The right sinus is usually continuous with the
superior sagittal sinus, and the left is
continuous with the straight sinus.
 The transverse sinuses receive the superior
petrosal sinuses, the inferior cerebral and
cerebellar veins, and the diploic veins.

23.  Each sinus occupies the
attached margin of the
tentorium cerebelli, grooving
the occipital bone and the
posteroinferior angle of the
parietal bone.
 They end by turning
downward as the sigmoid
sinuses.

24. The sigmoid sinuses
 are a direct continuation of the transverse
sinuses.
 Each sinus turns downward and medially and
grooves the mastoid part of the temporal bone.
 pass inferiorly through the posterior part of the
jugular foramen to become continuous with the
superior bulb of the internal jugular vein.

27. The sigmoid sinuses become continuous with the
superior bulb of the internal jugular vein.

28. The occipital sinus
 is a small sinus occupying
the attached margin of the
falx cerebelli.
 It commences near the
foramen magnum, where
it communicates with the
vertebral veins and drains
into the confluence of
sinuses.

29. The cavernous sinuses
 Situated in the middle
cranial fossa on each side
of the body of the sphenoid
bone.
 Each sinus extends from
the superior orbital fissure
to the apex of the petrous
part of the temporal bone.

30.  Numerous trabeculae cross their
interior, giving them a spongy
appearance.
 The two sinuses communicate with
each other by means of the anterior
and posterior intercavernous
sinuses,

31.  Tributaries : the superior and
inferior ophthalmic veins, the
inferior cerebral veins, the
sphenoparietal sinus, and the
central vein of the retina.
 The sinus drains posteriorly
into the superior and inferior
petrosal sinuses and inferiorly
into the pterygoid venous plexus.

34.  Each sinus has an
important
communication with the
facial vein through the
superior ophthalmic
vein.
 This is a route by which
infection can travel from
the facial skin to the
cavernous sinus.

39. Cavernous sinus Thrombosis
 Causes:
 Bacterial infection that has spread
from the sinuses, teeth, ears,
eyes, nose, or skin of the face
Symptoms:
 Bulging eyeball, usually on one
side of face
 Cannot move the eye in a
particular direction
 Drooping eyelids
 Headaches
 Vision loss

40.  Tests include:
 CT scan of the head
 Magnetic resonance imaging (MRI) of the
brain
 Magnetic resonance venogram
 Sinus x-ray
 Treatment:
 Cavernous sinus thrombosis is treated
with high-dose antibiotics given through a
vein (IV).
 Sometimes surgery is needed to drain

41. Petrosal sinuses
 The superior and inferior petrosal sinuses are
small sinuses situated on the superior and
inferior borders of the petrous part of the
temporal bone on each side of the skull.

42.  Each superior
sinus drains the
cavernous sinus into
the transverse
sinus
 Each inferior sinus
drains the
cavernous sinus into
the internal jugular
vein.

43. The flowing of the blood in dural
sinus
Sup. sagittal sinus
Inf. sagittal sinus Straight sinus Confluence of sinus Transverse sinus
Cavernous sinus
Sup. petrosal sinus
Inf. petrosal sinus Internal jugular vein
Sigmoid sinus