1. The document discusses the dural venous sinuses, their characteristics, classification, and the cavernous sinus in detail. 2. The dural venous sinuses drain blood from the brain and cranial cavity, absorb CSF, and receive valveless emissary veins. They are classified into unpaired and paired sinuses. 3. The cavernous sinus is a paired dural venous sinus located near the sphenoid bone. It contains the internal carotid artery and cranial nerves III and IV. Thrombosis or rupture of the cavernous sinus or internal carotid artery can cause symptoms like exophthalmos and ophthalmoplegia.

1. Dural venous sinuses
Lecture by
Dr.N.Mugunthan.MBBS.,M.S.,DNB.,MNAMS.,PhD.,
Associate Professor
MGMC&RI.

2. Learning objectives
• Dural venous sinuses – characteristics &
functions
• Classification
• Cavernous sinus in detail
• Applied anatomy
©Dr.N.Mugunthan

3. Dural venous sinuses
©Dr.N.Mugunthan

4. Characteristics & functions
Lined with endothelium
Devoid of muscular coat
Devoid of valves
Drain the blood from brain & cranial
cavity
Absorb CSF through arachnoid
granulation tissue
Receive valve less emissary vein to
maintain an equilibrium of venous
pressure
©Dr.N.Mugunthan

5. Classification
Unpaired sinuses
1. Superior sagittal sinus
2. Inferior sagittal sinus
3. straight sinus
4. occipital sinus
5. Anterior intercavernous sinus
6. Posterior intercavernous sinus
7. Basilar venous plexus
Paired sinuses
1. Transverse sinus
2. Sigmoid sinus
3. Cavernous sinus
4. Superior petrosal sinus
5. Inferior petrosal sinus
6. Spheno-parietal sinus
7. Petro-squamous sinus
8. Middle meningeal sinus
©Dr.N.Mugunthan

6. Unpaired sinuses
1. Superior sagittal sinus
2. Inferior sagittal sinus
3. Straight sinus
4. Occipital sinus
5. Anterior intercavernous
sinus
6. Posterior intercavernous
sinus
7. Basilar venous plexus
©Dr.N.Mugunthan

7. Paired sinuses
1. Transverse sinus
2. Sigmoid sinus
3. Cavernous sinus
4. Superior petrosal sinus
5. Inferior petrosal sinus
6. Spheno-parietal sinus
7. Petro-squamous sinus
8. Middle meningeal sinus
©Dr.N.Mugunthan

8. Cavernous sinus
 Paired dural venous sinus
Situation: on each side of body of
sphenoid bone.
Extent:
 Front – superior orbital fissure
 Behind -apex of petrous part of
temporal bone
©Dr.N.Mugunthan

9. Interior : traversed by reticular
fibers - spongy, hence
called – cavernous.
Measurements:
 Length : 2cm
 Breadth : 1cm
Formation: separation between
meningeal & endosteal
layer of duramater
Cavernous sinus cont…
©Dr.N.Mugunthan

10. Presenting parts
 Roof ,floor, medial & lateral wall.
 Roof & Lateral wall – meningeal
layer
 Floor & Medial wall – endosteal
layer
 Structures piercing roof:
 3rd & 4th cranial nerve
 Internal carotid artery
©Dr.N.Mugunthan

11. RELATIONS
Superiorly:
• Optic chiasma
• ICA [after piercing roof -
backward & upward(Carotid siphon)]
Inferiorly:
• Sphenoidal air sinus
Medially:
• Pituitary gland
Laterally:
• Cavum trigeminale
• Temporal lobe (uncus)
©Dr.N.Mugunthan

12. Structures passing through the sinus
1. Internal carotid artery:
Surrounded by sympathetic plexus
Runs along floor (carotid sulcus)
Turns upward pierce the roof
(carotido-clinoid foramen)
2. Abducent nerve:
Enters below petro-sphenoid
ligament
Inferolateral to ICA
©Dr.N.Mugunthan

13. Structures within the lateral wall of
cavernous sinus
• Separated from the venous
blood by endothelial lining of
the sinus
1. Oculomotor nerve
2. Trochlear nerve
(3rd & 4th nerve pierce the roof)
3. Ophthalmic nerve
4. Maxillary nerve
©Dr.N.Mugunthan

14. TRIBUTARIES
1. Superior ophthalmic vein
2. A branch from inferior ophthalmic
vein
3. Central vein of retina
4. Superficial middle cerebral vein
5. Inferior cerebral veins
6. Spheno-parietal sinus
7. Anterior trunk of middle meningeal
sinus (occasionally)
©Dr.N.Mugunthan

15. COMMUNICATIONS
1. With transverse sinus – via
superior petrosal sinus
2. With IJV –via inferior petrosal
sinus
3. With pterygoid venous plexus –
via emissary vein pass thro’
ovale,spinosum, vesalii &
lacerum
©Dr.N.Mugunthan

16. COMMUNICATIONS
4. With facial vein by 2 routes
Direct:
Sup.ophthalmic vein &
Angular vein
Indirect:
with pterygoid plexus via deep facial vein
5. With Superior Sagittal Sinus – Via
superficial middle cerebral & superior
anastomotic vein
6. With opposite cavernous sinus –via
anterior & posterior intercavernous
sinuses
©Dr.N.Mugunthan

17. Factors regulating blood flow in cavernous
sinus
Expansile pulsation of ICA
Gravity
Change of position of head
©Dr.N.Mugunthan

18. Applied anatomy
1.Thrombosis of cavernous sinus
Causes: communications from dangerous area
of face,orbit & pharynx
Symptoms:
• Pain in eye
• Oedema of eyelids
Signs:
• Ophthalmoplegia (3rd,4th & 6th nerves)
• Exophthalmos (congestion of orbital veins)
• Unilateral becomes bilateral due to
ant.&post.intercavernous sinuses
©Dr.N.Mugunthan

19. 2. # Base of skull
• ICA is ruptured
• Arterio-venous communications
Manifestations:
• Pulsating exophthalmos
• Oedema eyelids
• Ophthalmoplegia
• Systolic murmur over temporal region
Tmt: ligation of ICA (contralateral
hemiplegia)
Applied anatomy cont…
©Dr.N.Mugunthan

20. SUMMARY
• Dural venous sinuses –
characteristics & functions
• Classification
• Cavernous sinus in detail
• Applied anatomy
©Dr.N.Mugunthan