Venous Drainage of the Brain Presentation pptx

venous drainage of brain
dural venous sinus
brain
blood supply
dura
sagittal sinus

1. Venous Anatomy of the Brain Dr.A.Supriya (1 st year Post Graduate –Dept of Neurosurgery)

2. Peculiarities of Veins in CNS The cerebral veins DO NOT run together with the arteries They are VALVELESS,thin walls lack muscular tissue At numerous sites the veins are most adherent to the brain than arteries,this helps in imaging as the displacement of veins may provide more localizing information in neuroradiological studies Cerebral veins may pose obstacles during surgery of deep seated lesions and in meningioma surgeries along the SSS

3. Cerebral venous system (Gross Anatomy) C. V. drainage comprises of 3 segments:- 1) Outer/Superficial segment:- drains scalp, muscles, tendons by scalp veins 2) Intermediate segment:- draining skull, diploe, duramater by diploic veins, emissary veins, meningeal veins & dural venous sinuses 3) Cerebral segment:- draining brain proper by Superficial & Deep Cortical Veins

4. Cerebral venous system (Gross Anatomy)

5. Diploic veins

6. Emissary veins

7. Emissary veins

8. Meningeal Veins The small venous channels that drain the dura mater covering the cerebrum are called the meningeal veins They are actually small sinuses that usually accompany the meningeal arteries Course between the arteries and the overlying bone The meningeal veins receive diploid veins from the calvarium. The meningeal veins drain into the large dural sinuses along the cranial base at their lower margin and into the venous lacunae and superior sagittal sinus at their upper margin

9. Meningeal Veins

10. DURAL VENOUS SINUSES These are venous spaces, the wall of which are formed by dura mater,located between meningeal and periosteal layers of duramater Have an inner lining of endothelium, unlike other veins,these are composed of tough fibrous tissue of dura Hence they exhibit greater tautness and DO NOT collapse when injured Receive venous blood from brain, meninges and bones of skull. There are 23 venous sinuses, of which 8 are paired and 7 are unpaired.

11. DURAL VENOUS SINUSES

12. Dural venous sinuses Unpaired • 1. Superior sagittal • 2. Inferior sagittal • 3. Straight • 4. Occipital • 5. Ant. Intercavernous • 6.Post.Intercavernous • 7. Basilar venous plexus • Paired • 1. Transverse • 2. Sigmoid • 3. Cavernous • 4. Sup. Petrosal • 5. Inf. Petrosal • 6. Sphenoparietal • 7. Petrosquamous • 8. Middle meningeal

13. Superior Sagittal Sinus

14. Superior Sagittal Sinus Largest of venous sinuses Starts from Foramen caecum,grooves along the vault of the skull, extends posteriorly , ends at the internal occipital protruberance, where it continues as transverse sinus,majority of the venous drainage goes to right transverse sinus As it runs upwards and backwards,the sinus becomes progressively larger in size - 4mm diameter at the frontal region whereas 10mm at lambda Traingular in cross section

15. Superior Sagittal Sinus

16. SSS - Lacunae VENOUS LACUNAE Enlarged venous spaces, called lacunae, are contained in the dura mater adjoining the superior sagittal sinus • The lacunae may extend along the medial extent of the hemisphere adjacent to the falx and as far as 3 cm lateral over the convexity. • Entering or occluding a lacuna at operation does not necessarily result in occlusion of the cortical veins or the superior sagittal sinus because most of the veins course deep to the lacunae and usually empty directly into the sinus.

17. SSS deviation The SSS was deviated to the right side of the sagittal suture in 54% at the bregma and 64% at the midpoint of the sagittal suture and the lambda. The maximal deviation was approximately 10mm to the right side. It is usually located approximately 3.5mm at the bregma, 4.5mm at the midpoint of the sagittal suture, and 5.7mm at the lambda.

18. Inferior Sagittal Sinus It is a small channel that lies in the posterior 2/3 rd of lower concave free margin of falx cerebri Originates above the anterior portion of corpus callosum,enlarges as it courses posteriorly to join the Straight sinus Arises from union of veins from the adjacent parts of Falx,corpus callosum and cingulate gyrus Often forms “hook” like bend with apex directed forward

19. Inferior Sagittal Sinus

20. Inferior Sagittal Sinus Largest tributaries are peri callosal veins SSS may communicate through venous channels in the falx

21. Straight Sinus Originates behind the splenium of the corpus callosum at the union of the inferior sagittal sinus and the great vein It continues posteriorly and downward in the junction of the tentorium and falx. It may drain into either transverse sinus, but most commonly drains predominantly into the left transverse sinus.

22. Straight Sinus

23. Tranverse Sinus Two on both sides - right and left Originate at the torcular herophili and course laterally from the internal occipital protuberance , between the attachments of the tentorium to the inner surface of the occipital bone Becomes the Sigmoid sinus at the site just behind the petrous ridge, where the transverse and superior petrosal sinuses meet.

24. Transverse Sinus

25. Tranverse Sinus Right transverse sinus that is usually larger and receives the majority of the drainage from the superior sagittal sinus. The left transverse sinus is usually smaller and receives predominantly the drainage of the straight sinus. Thus, the right transverse sinus, right sigmoid sinus, and right jugular vein contain blood from the superficial parts of the brain And the left transverse sinus, left sigmoid sinus, and left internal jugular vein contain blood mainly from the deep parts of the brain drained by the internal cerebral, basal, and great veins

26. Sigmoid sinus Sigmoid sinus originates at the site just behind the petrous ridge, where the transverse and superior petrosal sinuses meet. Exits cranium as IJV

27. Tentorial Sinuses These are 2 constant sinuses – but rarely symmetrical – right and left tentorial sinuses Right tentorial sinus – formed by convergence of veins from superior surface of cerebellum Left tentorial sinus – formed by lateral and iinferior surfaces of occipital and temporal lobes

28. Cavernous sinuses The paired cavernous sinuses are situated on each side of the sella turcica,in middle cranial fossa and are connected across the midline by the anterior and posterior intercavernous sinuses

29. Cavernous sinuses Anteriorly, each cavernous sinus communicates with the sphenoparietal sinus and the ophthalmic veins Middle portion communicates through small veins that pass through the foramina spinosum and ovale Posteriorly, the cavernous sinus opens directly into the basilar sinus, which sits on the clivus. It communicates through the superior petrosal sinus with the junction of the transverse and sigmoid sinuses and through the inferior petrosal sinus with the sigmoid sinus

30. Cavernous sinuses

31. Cavernous sinuses In all communications, blood can flow in either directions. Can be sources of infection and thrombosis In cases of ottitis media and mastoid abcess the infection can pass through the superior and inferior petrosal sinuses to the cavernous sinus via the labyrinthine veins and the mastoid emissary veins. Dangerous area of the face: three points of triangle are the 2 corners of mouth and the bridge of nose. Infections from the face can spread in retrograde direction and cause thrombosis of the cavernous sinus via facial vein and pterygoid plexus.

32. Superior Petrosal Sinus The superior petrosal sinus courses within the attachment of the tentorium to the petrous ridge Its medial end connects with the posterior end of the cavernous sinus, and its lateral end joins the junction of the transverse and sigmoid sinuses.

33. Sphenoparietal, Sphenobasal, and Sphenopetrosal Sinuses The sphenoparietal sinus is the largest of the meningeal channels coursing with the meningeal arteries along the lesser wing of sphenoid It accompanies the anterior branch of the middle meningeal artery above the level of the pterion.

34. Occipital Sinus Smallest of Sinuses Lies in the attatched margin of Falx Cerebelli Communicates cranially with confluence of sinuses , caudally with vertebral venous plexus Sometimes it can deviate to one side to join sigmoid sinus – Oblique occipital sinus

35. CONFLUENCE OF SINUSES Latin confluens sinuum Torcular herophilli Is junction of following dural venous sinuses-SSS,Straight sinus,occipital sinus,Transverese sinus.

36. Anastamotic Veins The largest veins on the lateral surface are the veins of Trolard and Labbé and the superficial sylvian vein

37. Anastamotic Veins – Vein of Trolard The vein of Trolard, also called the superior anastomotic vein, is the largest anastomotic vein crossing the cortical surface of the frontal and parietal lobes between the superior sagittal sinus and the sylvian fissure Located at a site that would correspond to the precentral, central, or postcentral vein (most common)

38. Anastamotic Veins - Vein of Labbé The vein of Labbé, also called the inferior anastomotic vein, is the largest anastomotic channel that crosses the temporal lobe between the sylvian fissure –usually the midpoint of sylvian fissure to the anterior most part of transverse sinus

39. Anastamotic Veins – Sup. Sylvian Vein The superficial sylvian vein usually arises at the posterior end of the sylvian fissure and courses anteriorly and inferiorly along the lips of the fissure It penetrates the arachnoid covering the anterior end of the sylvian fissure and joins the sphenoparietal sinus

40. Cerebral venous system (Gross Anatomy) C. V. drainage comprises of 3 segments:- 1) Outer/Superficial segment:- drains scalp, muscles, tendons by scalp veins 2) Intermediate segment:- draining skull, diploe, duramater by Diploic veins, Emissary veins, Meningeal veins & Dural venous sinuses 3) Cerebral segment:- draining brain proper by Superficial & Deep Cortical Veins

41. Cortical veins Superficial Cortical veins Deep Cortical veins

42. Superficial Cortical veins The superficial venous network is comprised of vessels coursing on the cortical surface, and collecting blood from the outer 1–2 cm of the cerebral cortex and subcortical white matter. This group of cortical veins terminate by exiting the subarachnoid space to become bridging veins that cross the subdural space and empty into the venous sinuses in the dura mater.

43. Bridging Veins Divided into 4 groups based on their site of termination:- 1. Superior sagittal group 2. Tentorial group, which drain into transverse or lateral tentorial sinus 3. Sphenoidal group, drain into sphenoparietal or cavernous sinus 4. Falcine group, drain into straight or inf sagittal sinus

44. Superficial Cortical veins Divided into 3 groups based on whether they drain the lateral, medial, inferior surface of the hemisphere Lateral (Frontal,temporal,parietal,occipital) Medial (Frontal,temporal,parietal,occipital) Inferior (Frontal,temporal,parietal,occipital)

45. Superficial Cortical veins - Frontal Divided into groups that drain the Lateral Medial Basal / Inferior surfaces of the lobe

46. Superficial Cortical veins Frontal-Lateral Ascending group Descending group Drain into SSS Frontopolar Anterior frontal Middle frontal posterior frontal Precentral central veins. Drain into Sylvian vein Fronto Sylvian

47. Superficial Cortical veins Frontal-Lateral

48. Superficial Cortical veins Frontal-Medial Ascending group Descending group Drain into SSS Anterior Medial Frontal Centro Medial Frontal posterior Medial Frontal Paracentral Drain into ISS Anterior Cerebral Pericallosal (Anterior)

49. Superficial Cortical veins Frontal-Medial

50. Superficial Cortical veins Frontal-Basal / Inferior Anterior Posterior Drain into SSS Anterior Orbitofrontal Drain into Basal Vein Posterior Orbitofrontal Olfactory

51. Superficial Cortical veins - Parietal Lateral Medial

52. Superficial Cortical veins Parietal-Lateral Ascending group Descending group Drain into SSS Central Post central Anterior Parietal Posterior Parietal Drain into Sylvian vein Parieto Sylvian

53. Superficial Cortical veins Parietal-Lateral

54. Superficial Cortical veins Parietal-Medial Ascending group Descending group Drain into SSS Paracentral Anterior Medial Parietal Posterior Medial Parietal Drain into Great Vein of Galen Pericallosal (Posterior)

55. Superficial Cortical veins Parietal-Medial

56. Superficial Cortical veins - Temporal Lateral Basal/Inferior

57. Superficial Cortical veins Temporal-Lateral Ascending group Descending group Drain into Sylvian vein Temporo Sylvian Drain into Basal Sinuses Anterior temporal veins Middle temporal veins Posterior temporal veins

58. Superficial Cortical veins Temporal-Lateral

59. Superficial Cortical veins Temporal-Basal/Inferior Lateral Medial Drain into Tentorial Sinuses Anterior Middle Posterior temporobasal veins Drain into Basal vein Medial temporal vein Uncal vein Hippocampal vein

60. Superficial Cortical veins - Occipital Divided into groups that drain the Lateral Medial Basal / Inferior surfaces of the lobe

61. Superficial Cortical veins - Occipital Lateral occipital veins are directed forward rather than backward , and enter the superior sagittal sinus for a distance of 4 to 5 cm proximal to the torcular herophili Medial surface of the occipital lobe is drained by the anterior and posterior calcarine veins The inferior surface of the occipital lobe is drained by the occipitobasal vein. – finally medial and inferior surface veins darin into Basal vein

62. Superficial Cortical veins - Occipital

63. Cerebral venous system (Gross Anatomy) C. V. drainage comprises of 3 segments:- 1) Outer/Superficial segment:- drains scalp, muscles, tendons by scalp veins 2) Intermediate segment:- draining skull, diploe, duramater by Diploic veins, Emissary veins, Meningeal veins & Dural venous sinuses 3) Cerebral segment:- draining brain proper by Superficial & Deep Cortical Veins

64. Deep Cortical Veins Drain the deep white matter,Choroid plexus,Diencephalon,Basal Ganglia Drain into Internal cerebral veins and Great cerebral vein of Galen

65. Deep Cortical Veins 2 groups Ventricular group Internal Cerebral veins Cisternal group Basal veins and Great vein of Galen

66. Deep Cortical Veins

67. Deep Cortical Veins- skyblue and purple

68. Deep Cortical Veins –Internal Cerebral Located near the midline in the tela choridea of the roof of 3 rd ventricle Extend caudally from interventricular foramina to quadrigeminal cistern Recieves Thalamo striate vein Choroidal vein Septal vein Epithalamic vein Lat.Ventricular vein There these paired veins join with Basal vein to form Great Cerebral Vein(Galen)

69. Deep Cortical Veins – Basal Vein Basal vein of Rosenthal arises near medial part of the anterior temporal lobe Recieves blood from Anterior cerebral vein Deep middle cerebral vein Inferior striate vein

70. Deep Cortical Veins –Great Cerebral of Galen Recieves drainage from Paired internal cerebral veins Paired basal veins Paired ccipital veins Posterior callosal vein This short vein passes caudally beneath the splenium of corpus callosum Empties into Straight sinus

71. Outlook of Venous Drainage

72. APPLIED ASPECTS CAVERNOUS SINUS THROMBOSIS Infections of dangerous area of face, Mortality -60% CEREBRAL VENOUS THROMBOSIS F:M 3:1,RISK FACTORS-OCP,PREGNANCY,Alcohol intake Symptoms –headache,vomiting,altered sensorium Signs –focal neurological deficits(60%),seizures(40%)

73. REFERENCES Rhotons Cranial anatomy of neurosurgery Greys anatomy book IB SINGH neuroanatomy Greenbergh handbook of neurosurgery

74. THANK YOU