DURAL VENOUS SINUSES WITH CLINICAL ANATOMY 2021

FEATURES OF DURAL VENOUS SINUSES -CLASSIFICATION OF SINUSES PAIRED & UNPAIRED-SUPERIOR SAGITTAL SINUS-INFERIOR SAGITTAL SINUS-STRAIGHT SINUS-TRANSVERSE SINUS-SIGMOID SINUSES-SUPERIOR AND INFERIOR PETROSAL SINUSES-OCCIPITAL SINUS-BASILAR VENOUS SINUS-SPHENOPARIETAL SINUS-PETROSQUAMOUS SINUS
ANTERIOR AND POSTERIOR INTERCAVERNOUS SINUSES-CAVERNOUS SINUS-RELATIONS-STRUCTURES PRESENT IN THE LATERAL WALL-STRUCTURES PASSING THROUGH CAVERNOUS SINUS-TRIBUTARIES OF CAVERNOUS SINUS-COMMUNICATIONS OF CAVERNOUS SINUS & APPLIED ANATOMY

1. DURAL VENOUS SINUSES DR.M.MD. MUSTAFA SHARIFF DEPT. OF ANATOMY SENIOR LECTURER SRM DENTAL COLLEGE & HOSPITAL RAMAPURAM –CHENNAI-89

2. FEATURES OF DURAL VENOUS SINUSES Lie between layers of Duramater Have no muscles in their walls Lined by endothelium Valves are absent Receives venous blood and CSF

3. CLASSIFICATION OF SINUSES PAIRED & UNPAIRED UNPAIRED SINUSES 1.Superior Sagittal 2.Inferior Sagittal 3.Straight 4.Occipital 5.Anterior Intercavernous 6.Posterior Intercavernous 7.Basilar venous plexus PAIRED SINUSES 1.Cavernous 2.Superio Petrosal 3.Inferior Petrosal 4.Transverse 5.Sigmoid 6.Sphenoparietal 7.Petrosquamous

4. SUPERIOR SAGITTAL SINUS 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, grooving the vault of the skull and at the internal occipital protuberance it deviates to one side ( usually the right ) and becomes continuous with the transverse sinus.

5. It communicates through small openings with 2 or 3 venous lacunae on each side. Numerous arachnoid villi and granulations project into these lacunae which also receive the diploic; emissary and meningeal veins. It receives the superior cerebral veins . At the internal occipital protuberance it is dilated to form the confluence of the sinuses which is connected to the opposite transverse sinus and receives the occipital si nus.

6. SUPERIOR SAGITTAL SINUS

7. CLINICAL ANATOMY Thrombosis of superior sagittal sinus: The spread of infection from nose, scalp and dipole to the superior sagittal sinus may cause its thrombosis. The presenting feature of thrombosis are: Marked increase in intracranial pressure, due to defective adsorption of CSF and (b) Delirium due to congestion of superior cerebral veins

8. INFERIOR SAGITTAL SINUS It occupies the free lower margin of the falx cerebri. It runs backward and joins the great cerebral vein which is formed by the union of the 2 internal cerebral veins at the free margin of the tentorium cerebelli to form the straight sinus. It receives cerebral veins from the medial surface of the cerebral hemisphere

9. INFERIOR SAGITTAL SINUS

10. STRAIGHT SINUS 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

11. STRAIGHT SINUS

12. TRANSVERSE SINUS 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. Each sinus occupies the attached margin of the tentorium cerebelli , grooving the occipital bone and posteroinferior angle of the parietal bone. They receive the superior petrosal sinuses ; inferior cerebral and cerebellar veins and diploic veins . They end by turning downward as the sigmoid sinuses

13. TRANSVERSE SINUS

14. SIGMOID SINUSES They are a direct continuation of the transverse sinuses. Each sinus turns downward and medially and grooves the mastoid part of the temporal 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.

15. SIGMOID SINUS

16. CLINICAL ANATOMY The sigmoid sinus is separated from mastoid antrum and mastoid air cells only by thin plate of bone. The thrombosis of the sigmoid sinus is therefore secondary to infection of the middle ear or mastoid process. Further utmost care should be taken not to expose sigmoid sinus during operations on the mastoid process.

17. SUPERIOR AND INFERIOR PETROSAL SINUSES 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 transverse sinus . Each inferior sinus drains the cavernous sinus into the internal jugular vein

18. SUPERIOR AND INFERIOR PETROSAL SINUSES

19. OCCIPITAL SINUS It is a small sinus occupying the attached margin of the falx cerebelli. It communicates with the vertebral veins near the foramen magnum. Superiorly it drains into the confluence of sinuses

20. APPLIED ANATOMY Confluence of sinuses ( torcular herophili ): It is the region where the superior sagittal and straight sinuses end and the right and left transverse sinuses begin. The occipital sinus also drains into the confluence. The confluence of sinuses is situated near the internal occipital protuberance.

21. BASILAR VENOUS SINUS It consists of network of veins lying between the two layers of dura on the clivus. It connects the two inferior petrosal sinuses and communicates with the internal vertebral venous plexus . It receives blood from the pons and medulla. Thrombosis of the basilar venous plexus is, therefore, usually fatal.

22. SPHENOPARIETAL SINUS The Sphenoparietal sinus lies along the posterior free margin of the lesser wing of the sphenoid and drains into the anterior part of the cavernous sinus . PETROSQUAMOUS SINUS This sinus lies in the petrosquamous suture if present and drains into the transverse sinus.

23. ANTERIOR AND POSTERIOR INTERCAVERNOUS SINUSES The anterior and posterior intercavernous sinuses connect the cavernous sinuses. They pass through diaphragma sellae in front and behind the opening for infundibulum of the pituitary gland, respectively. Intercavernous sinuses and cavernous sinuses together form the circular sinus.

24. CAVERNOUS SINUS Location:- They are situated in the middle cranial fossa on each side of the body of the sphenoid bone. Extent:- Each sinus extends from the superior orbital fissure in front to the apex of the petrous part of the temporal bone behind

25. CAVERNOUS SINUS

26. RELATIONS Superior:- Optic chiasma,Optic tract, Internal carotid artery, Anterior perforated substance Inferior:- Foramen lacerum,Junction of body and greater wing of sphenoid bone Medial:- Pituitary gland , sphenoid air sinus

27. Lateral:- Temporal lobe , cavum trigeminale Anterior:- Superior orbital fissure, Apex of Orbit Posterior:- Crus cerebri, Apex of petrous temporal bone RELATIONS

28. STRUCTURES PRESENT IN THE LATERAL WALL From above downwards Oculomotor nerve Trochlear nerve Ophthalmic nerve Maxillary nerve

29. STRUCTURES PASSING THROUGH CAVERNOUS SINUS Internal carotid artery surrounded by sympathetic plexus Abducent nerve

30. TRIBUTARIES OF CAVERNOUS SINUS From orbit:- Superior opthalmic vein Inferior ophthalmic vein Central vein of retina From meninges:- Sphenoparietal sinus Anterior trunk of middle meningeal vein

31. TRIBUTARIES OF CAVERNOUS SINUS From brain:- Superficial middle cerebral vein Inferior cerebral vein

32. COMMUNICATIONS OF CAVERNOUS SINUS Transverse sinus via superior petrosal sinus. Internal jugular vein via inferior petrosal sinus. Pterygoid venous plexus via emissary veins communicate through foramen ovale,lacerum. Facial vein via deep facial veins.

33. Opposite cavernous sinus via anterior and posterior Intercavernous sinus. Superior sagittal sinus via superficial middle cerebral vein and superior anastomotic vein. Internal vertebral venous plexus via basilar venous plexus.

34. APPLIED ANATOMY Cavernous sinus thrombosis:- Septic thrombosis of cavernous sinus may be caused by its numerous communications Symptoms:- Severe pain in eye and forehead Opthalmoplegia (paralysis of ocular muscles) Exophthalmus (abnormal protrusion of the eyeball or eyeballs)

35. Arteriovenous communication: If the internal carotid artery is ruptured in the fracture base of the skull, an arteriovenous communication/fistula is established between the artery and cavernous sinus. Consequently, arterial blood rushes into the cavernous sinus, enlarging it and forcing blood into the connecting veins.

36. Arteriovenous communication gives rise to the following signs and symptoms: 1. Pulsating exophthalmos; the eyeball protrudes and pulsates with each heartbeat 2. A loud bruit (loud systolic murmur) is easily heard over the eye. 3. Ophthalmoplegia due to involvement of the 3rd, 4th, and 6th cranial nerves. 4. Marked orbital and conjunctival edema due to raised venous pressure in the cavernous sinus.

37. REFERENCES HEAD & NECK IIIRD VOLUME VISHRAM SINGH EXAM-ORINTED ANATOMY SHOUKAT N.KAZI HEAD & NECK AK DATTA 5 TH EDITION GRAYS ANATOMY STUDENTS EDITION CLINCAL ANATOMY SNELL 8 TH EDITION CLINICAL ANATOMY MOORE 5 TH EDITION HEAD & NECK BD CHAURASIA’S 4 TH EDITION HEAD & NECK DR. AS.MONI

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