For medical, nursing, and physiotherapy undergraduates, and postgraduates

1. DURAL VENOUS
SINUSES

2. INTERIOR OF CRANIUM

3. MENINGES
• Three layers
• Three Spaces
• Fold of Dura mater
• Function

4. MENINGES

5. MENINGES

6. DURAL VENOUS SINUSES
 They are lodges along the lines of separation
between the Endosteal and the Meningeal
layers.
 They receive blood from :
1. The Brain and its meninges
2. Bones of Calvaria via Diploic veins

7. DURAL VENOUS SINUSES
 These communicate with Extra cranial veins
through Emissary veins.
 They occupy the space between the endosteal
and meningeal layers of duramater except

8. CHARACTERISTICS
 Lined by endothelium, devoid of muscular
coat and are valveless.
 They collect blood from the brain, meninges,
diploe and from internal ear and orbit.
 Absorb CSF through the arachnoid granulation
tissue.
 Receive valveless emissary veins to maintain

9. CLASSIFICATION
 Unpaired Sinuses
1. Superior sagittal
2. Inferior sagittal
3. Straight
4. Occipital
5. Anterior inter-
cavernous
6. Posterior inter-
cavernous
7. Basilar venous plexus
Paired Sinuses
1. Transverse
2. Sigmoid
3. Cavernous
4. Superior petrosal
5. Inferior petrosal
6. Spheno-parietal
7. Petro-squamous
8. Middle meningeal

12. SUPERIOR SAGITTAL SINUS
 Lies within the convex attached margin of Falx
cerebri.
 Begins at the Crista galli pass backwards and
gradually increases in size.
 Triangular in cross-section

13. SUPERIOR SAGITTAL SINUS
 On reaching Internal occipital protuberance, it
deviates to the right and becomes continuous
with Right transverse sinus.
 Sometimes it deviates to left or
 It bifurcates to open into both transverse
sinuses.

14. CONFLUENCE OF SINUSES
 It is the dilated posterior end of the superior
sagittal sinus.
 It lodges in a depression usually on the right side
of the Internal occipital protuberance.
 Right transverse sinus begins from the
confluence.
 Left transverse sinus is connected with the
confluence through a communicating vein.

16. INTERIOR OF SINUS
 Presents the following openings :
1. Openings of Superior Cerebral veins
2. Arachnoid granulations project into its interior for
absorption of CSF.
3. Numerous fibrous bands cross the inferior angle of
sinus.
4. Openings of three venous lacunae on each side of
sinus.

17. TRIBUTARIES
1. Superior Cerebral veins :
• 8-12 in number
• Collect blood from supero-lateral & medial
surface of cerebral hemispheres.
2. Parietal emissary veins :
3. Venous Lacunae :
• Three on each side, which in turn receive
Diploic and meningeal veins.

18. COMMUNICATIONS
1. With veins of scalp – parietal emissary veins
2. Vein from the nose – through patent foramen
caecum
3. With cavernous sinus – through superior
anastomotic vein or superficial middle
cerebral vein.

19. INFERIOR SAGITTAL SINUS
 It occupies the Posterior 2/3rd of the lower
concave free margin of Falx cerebri.
 It collects blood from medial surface of
cerebrum, Falx Cerebri.
 It ends by joining the Great Cerebral vein to
form the Straight sinus.

21. STRAIGHT SINUS
 It is situated in median plane within the junction
of Falx Cerebri and Tentorium Cerebelli.
 It is formed by the union of Inferior Sagittal sinus
& Great Cerebral vein.
 It terminates at Internal Occipital protuberance
by continuing as Left Transverse sinus.

22. TRIBUTARIES
1. Inferior Sagittal sinus
2. A few Superior Cerebellar veins
3. Great Cerebral vein (of Galen)

23. OCCIPITAL SINUS
 It is the smallest sinus and situated along the
attached margin of Falx Cerebelli.
 It begins as small radicles near the margin of
Foramen Magnum.
 It terminates in the confluence of sinuses.

24. ANTERIOR INTERCAVERNOUS
SINUS
 It traverses Anterior attached margin of
Diaphragma Sellae in front of infundibulum.
 It connects the cavernous sinus of both sides.

25. POSTERIOR INTERCAVERNOUS
SINUS
 It traverses Posterior attached margin of
Diaphragma sellae behind the infundibulum.
 It connects the cavernous sinus of both sides

26. BASILAR VENOUS SINUS
 It’s a plexiform venous network lying on the
Clivus of skull.
 It connects laterally the Inferior Petrosal sinus
of both sides.
 It communicates with the Internal Vertebral
Venous plexus below through the Foramen
Magnum.

27. CAVERNOUS
SINUS

30. INTRODUCTION
 These are paired sinuses situated on each side
of body of sphenoid bone.

31. EXTENT
 From Superior Orbital Fissure to the Apex of
Petrous Temporal Bone.
 Measurements :
 Length : 2 cm
 Breadth : 1 cm

33. FORMATION
 It is formed by separation between meningeal
and endosteal layers of Dura.
 It is lined by endothelium and filled with
venous blood.

34. FORMATION
 Roof and lateral wall : Meningeal layer
 Floor and medial wall : Endosteal layer.

35. STRUCTURES PASSING THROUGH THE
SINUS
1. Internal Carotid artery surrounded by a
plexus of sympathetic nerves and veins.
2. Abducent nerve : Lies infero-lateral to the ICA
and leaves through Superior orbital fissure
within the Common tendinous ring.

38. STRUCTURES WITHIN THE LATERAL
WALL OF SINUS
1. Oculomotor nerve : enters by piercing the
roof and leaves through Superior orbital
fissure within tendinous ring.
2. Trochlear nerve : enters by piercing the roof
and leaves through Superior orbital fissure
outside the tendinous ring.

40. STRUCTURES WITHIN THE LATERAL
WALL OF SINUS
3. Opthalmic nerve : enters by piercing lateral
wall of sinus and leaves through superior
orbital fissure by dividing into Lacrimal,
frontal and Naso-ciliary nerves.
4. Maxillary nerve : enters by piercing lateral
wall and leaves through Foramen Rotundum.

41. EXTERNAL RELATIONS
 Medially and below :
1. Hypophysis cerebri
2. Sphenoidal air sinus
 Laterally :
1. Cavum Trigeminale containing Trigeminal
ganglion
2. Uncus of temporal lobe

42. EXTERNAL RELATIONS
 Above :
1. A part of Optic Chiasma
2. Internal Carotid Artery

44. TRIBUTARIES
1. Superior Opthalmic vein
2. Inferior Opthalmic vein (a branch)
3. Central vein of retina (sometimes)
4. Superficial middle cerebral vein
5. Inferior cerebral veins (few)
6. Spheno-parietal sinus
7. Anterior trunk of Middle Meningeal vein
(sometimes)

47. COMMUNICATIONS
1. With Transverse sinus : via superior petrosal
sinus
2. With Internal Jugular vein : through Inferior
Petrosal sinus and a plexus of veins around
Internal carotid artery.
3. With Pterygoid venous plexus : through
emissary veins passing through Foramen Ovale,
Foramen Spinosum, Foramen Vesalii And
Foramen Lacerum.

48. COMMUNICATIONS
4. With Facial artery by two routes :
i. Superior Opthalmic vein and Angular vein
ii. Pterygoid venous plexus and Deep facial vein.
5. With opposite Cavernous sinus via Anterior
and posterior inter-cavernous sinuses.
6. With Superior Sagittal sinus – through the
superficial middle cerebral vein and superior
anastomotic vein.

49. FACTORS REGULATING BLOOD FLOW
1. Expansile pulsation of Internal carotid artery.
2. By gravity
3. Change in position of head

50. APPLIED ANATOMY
 Thombosis of Superior sagittal sinus may take
place d/t spread of infection from nose, scalp
and diploic tissue.
 Thrombosis of Sigmoid sinus may take place
from the infected middle ear or mastoid
antrum.
 Thrombosis of Inferior Petrosal sinus may take
place from infection in middle & internal ear.

51. APPLIED ANATOMY
 Septic thrombosis of cavernous sinus may be
caused through numerous communications
from dangerous area of face, orbit and
pharynx.
i. Severe pain in eye, forehead along
distribution of Opthalmic nerve
ii. Opthalmoplegia d/t involvement of 3rd,4th &
6th cranial nerve.
iii. Marked oedema of eyelids and exopthalmos.

52. APPLIED ANATOMY
 ICA can be ruptured in fracture of base of
skull, leading to establishment of arterio-
venous communication between cavernous
sinus and ICA.
i. Pulsating exopthalmos
ii. Oedema of eyelids
iii. Partial or complete opthalmoplegia
iv. Loud systolic murmur over temporal region

53. APPLIED ANATOMY
 The middle meningeal veins are closer to the
bones than the arteries. The grooves on
parietal bones are caused due to veins which
are more liable to be torn in fracture.

54. TRANSVERSE SINUS
 Introduction :
 Tributaries are :
1. Superior petrosal sinus
2. Inferior cerebral veins
3. Inferior cerebellar veins
4. Diploic vein
5. Inferior Anastomotic vein

55. SIGMOID SINUS
 Right and Left sided
 S shaped
 Extends from the Postero-inferior angle of
parietal bone to the posterior part of Jugular
foramen.
 It continues as Superior bulb of Internal
Jugular vein.

56. SIGMOID SINUS
 It grooves the mastoid part of temporal bone
and lies close to mastoid antrum and mastoid
air cells.
• Tributaries :
1. Mastoid and condylar emissary veins
2. Cerebellar veins
3. Internal auditory vein

57. SUPERIOR PETROSAL SINUS
• Connects Cavernous sinus with Transverse
sinus.
• Each sinus lodges in a groove along the upper
border of petrous part of temporal bone.
• Tributaries :
– Inferior cerebral veins
– Some cerebellar veins
– veins from tympanic cavity

58. INFERIOR PETROSAL SINUS
• Connects Cavernous sinus with Superior bulb of
Internal jugular vein.
• Each sinus lodges in a groove along the
articulation between the petrous part of
temporal bone and basio-occiput.
• Tributaries :
– Labyrinthine veins
– veins from medulla, pons and cerebellum.

59. SPHENO-PARIETAL SINUS
• Situated along the undersurface of posterior
border of lesser wing of sphenoid bone.
• Drain into cavernous sinuses.

60. PETRO-SQUAMOUS SINUS
• Lodge in petro-squamous suture
• Drain into Transverse sinus.

61. MIDDLE MENINGEAL VEINS
• Better called as Sinuses.
• They accompany the branches of middle
meningeal artery and consists of :
1. Anterior
2. Posterior trunk

62. THANK YOU