Cerebral hemisphere and Lateral ventricular Venous Anatomy

Venous anatomy of the cerebral hemispheres and lateral ventricles with discussion of superficial and deep venous anatomy of the supratentorial and incisural space of brain. Different aspects for various surgical approaches for different regions of brain pathologies.

1. Cerebral Venous Anatomy Moderated by : Dr V.C. Jha Dr Gaurav Verma Dr Nitish Kumar Dr Vivek Sinha Presented By:- Dr Rahul Jain SR-3 Neurosurgery

2. Introduction The cerebral veins are divided into a superficial group and a deep group . The superficial group drains the cortical surfaces. The deep group drains the deep white and gray matter and collects into channels that course through the walls of the ventricles and basal cisterns to drain into the internal cerebral, basal, and great veins The superficial venous system drains the superficial one-fifth of the thickness of the cerebrum, whereas the deep venous system drains the other four-fifths of the depth of the cerebrum.

3. THE SUPERFICIAL VEINS Drain the cortical surfaces . Four groups of bridging veins Superior sagittal group that drains into the superior sagittal sinus Sphenoidal group that drains into the sphenoparietal or cavernous sinus Tentorial group that converges on the sinuses in the tentorium Falcine group that empties into the inferior sagittal or straight sinus, or their tributaries

4. Superior sagittal group is composed of the veins that drain into the superior sagittal sinus. Includes the veins from the superior part of the medial and lateral surfaces of the frontal, parietal, and occipital lobes and from the anterior part of the orbital surface of the frontal lobe. Usually have a free segment of vein, 1 to 2 cm in length, in the subdural space between the vein's exit from its bed in the pia-arachnoid and its entrance into the sinus. Sphenoidal group is formed by the bridging veins that empty into the sinuses that course on the inner surface of the sphenoid bone.

5. Formed by the terminal ends of the superficial sylvian and occasionally the deep sylvian veins. Drains the part of the frontal, temporal, and parietal lobes adjoining the sylvian fissure into the sphenoparietal or cavernous sinus. Tentorial Group drains into the sinuses coursing in the tentorium, called the tentorial sinuses , or into the transverse and superior petrosal sinuses. Drain the lateral surface of the temporal lobe and the basal surface of the temporal and occipital lobes. This group includes the temporobasal and occipitobasal veins and the descending veins , including the vein of Labbé , from the lateral surface of the temporal lobe.

6. Falcine Group formed by the veins that empty into the inferior sagittal or straight sinus, either directly or through the internal cerebral, basal, and great veins. The cortical area drained by the falcine group corresponds roughly to the limbic lobe. The largest cortical areas are the parahippocampal and cingulate gyri, but the area also includes the paraterminal , paraolfactory gyri, and the uncus . The superior sagittal, sphenoidal, or tentorial group may drain the majority of the hemisphere if its tributaries are large.

7. superior sagittal group (dark blue) ; tentorial group (green) ; sphenoidal group (red) ; falcine group (purple)

8. Dural Sinuses and Veins Dural sinuses into which the cortical veins empty are the superior and inferior sagittal, straight, transverse, tentorial , cavernous, sphenoparietal , sphenobasal , and sphenopetrosal sinuses . These sinuses form the terminal part of the superficial cortical venous system.

9. Superior Sagittal Sinus and Venous Lacunae Courses in the midline beginning just behind the frontal sinuses and grows larger as it continues posteriorly in the shallow groove on the inner table of the cranium. communicate through the foramen cecum with the veins of the nasal cavity. It drains into the transverse sinus (predominantly right side) at the internal occipital protuberance through a plexiform confluent venous complex, called the torcular herophili .

10. The superior sagittal sinus drains the anterior part of the inferior surface of the frontal lobe and the superior portions of the lateral and medial surfaces of the frontal, parietal, and occipital lobes . The veins from each cortical area join the superior sagittal sinus in a characteristic configuration . The veins arising near the frontal pole are directed posteriorly, in the usual direction of flow within the sinus , at their junction with the sinus. The veins arising from the posterior part of the frontal, parietal and occipital lobe are directed forward as they join the sinus, in a direction opposed to the direction of flow within the sinus.

11. Enlarged venous spaces, called lacunae , are contained in the dura mater adjoining the superior sagittal sinus. Lacunae are largest and most constant in the parietal and posterior frontal regions. Lacunae receive predominantly the drainage of the meningeal veins, which accompany the meningeal arteries in the dura mater. Cortical veins that empty into the superior sagittal sinus characteristically pass beneath rather than emptying directly into the lacunae to reach the sinus .

12. Inferior Sagittal Sinus Courses in the inferior edge of the falx . Originates above the anterior portion of the corpus callosum and enlarges as it courses posteriorly to join the straight sinus . The largest tributaries of the inferior sagittal sinus are the anterior pericallosal veins . Straight sinus originates behind the selenium of the corpus callosum at the union of the inferior sagittal sinus and the great vein. Drains predominantly into left transverse sinus.

13. Transverse Sinus Right and left transverse sinuses originate at the torcular herophili and course laterally from the internal occipital protuberance in a shallow groove between the attachments of the tentorium to the inner surface of the occipital bone. Transverse sinus exits the tentorial attachments to become the sigmoid sinus at the site just behind the petrous ridge, where the transverse and superior petrosal sinuses meet . Left transverse sinus is usually smaller and receives predominantly the drainage of the straight sinus.

14. 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 . The difference in symptoms caused by blockage of the venous drainage on one side or the other and the differences in Queckenstedt's sign with compression of the jugular veins on either the left or right side.

15. Tentorial Sinuses Medial tentorial sinuses are formed by the convergence of veins from the superior surface of the cerebellum. Lateral tentorial sinuses are formed by the convergence of veins from the basal and lateral surfaces of the temporal and occipital lobes. The lateral tentorial sinuses arise within the lateral part of the tentorium and course laterally to drain into the terminal portion of the transverse sinus. The medial tentorial sinuses course medially to empty into the straight sinus or the junction of the straight and transverse sinuses.

16. Cavernous Sinus They are paired, are situated on each side of the sella turcica and are connected across the midline by the anterior and posterior intercavernous sinuses.

17. 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 . Sphenoparietal sinus is the largest of the meningeal channels coursing with the meningeal arteries. The sinus coursing along the sphenoid ridge below pterion level may turn inferiorly to reach the floor of the middle cranial fossa. Then it courses posteriorly to empty into a lateral extension of the cavernous sinus on the greater sphenoid wing.

18. The variant in which the sinus exits the cranium by joining the sphenoidal emissary veins and the pterygoid plexus is referred to as the sphenobasal sinus , The variant in which the sinus courses further posteriorly along the floor of the middle fossa and drains into the superior petrosal or lateral sinus is called the sphenopetrosal sinus . The superficial sylvian veins commonly empty into the sphenoparietal sinus. If the sphenoparietal sinus is absent or poorly developed, the sylvian veins may drain directly into the cavernous sinus or they may turn inferiorly around the anterior pole and inferior surface of the temporal lobe to empty into the sphenobasal or sphenopetrosal sinuses .

19. Anastomotic Veins The largest veins on the lateral surface are the veins of Trolard and Labbé and the superficial sylvian veins. The Vein of Trolard is the largest anastomotic vein joining the superior sagittal sinus with the veins along the sylvian fissure . The Vein of Labbé is the largest vein connecting the veins along the sylvian fissure with the transverse sinus. The superficial sylvian vein courses along the surface of the sylvian fissure and drains predominantly into the dural sinuses along the sphenoid ridge.

20. Vein of Trolard AKA superior anastomotic vein, largest anastomotic vein crossing the cortical surface of the frontal and parietal lobes between the superior sagittal sinus and the sylvian fissure. Vein of Trolard correspond to the precentral, central, or postcentral vein . The vein of Trolard usually joins the superior sagittal sinus as a single channel that is directed forward against the direction of flow as it joins the sinus.

21. Vein of Labbé AKA inferior anastomotic vein, is the largest anastomotic channel that crosses the temporal lobe between the sylvian fissure and the transverse sinus. It usually arises from the middle portion of the sylvian fissure and is directed posteriorly and inferiorly toward t he anterior part of the transverse sinus.

22. Superficial Sylvian Vein Usually arises at the posterior end of the sylvian fissure and courses anteriorly and inferiorly along the lips of the fissure. Superficial sylvian vein receives the frontosylvian , parietosylvian , and temporosylvian veins and commonly anastomoses with the veins of Trolard and Labbé . It penetrates the arachnoid covering the anterior end of the sylvian fissure and joins the sphenoparietal sinus.

23. Cortical Veins Three groups based on whether they drain the lateral, medial, or inferior surface of the hemisphere. The largest 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 . The veins draining the adjacent areas on the medial, lateral, and inferior surfaces may join along the margins of the hemisphere to form a single bridging vein before emptying into one of the sinuses.

24. THE DEEP VEINS Deep venous system collects into channels that course through the walls of the ventricles and basal cisterns and converge on the internal cerebral, basal, and great veins. During operations on the lateral ventricles, the deep veins more commonly provide orienting landmarks than the arteries because the arteries in the ventricular walls are small and poorly seen and the veins are larger and are easily visible through the ependyma . The deep veins are divided into a ventricular group , composed of the veins draining the walls of the lateral ventricles, and a cisternal group , which includes the veins draining the walls of the basal cisterns.

25. VENTRICULAR GROUP Arise from tributaries that drain the basal ganglia, thalamus, internal capsule, corpus callosum , septum pellucidum , fornix, and deep white matter. These tributaries converge on the lateral edge of the lateral ventricles, where they split medial or lateral groups based on whether they course through the forniceal or the thalamic side of the choroidal fissure . Both groups course along the walls of the ventricle in a subependymal location toward the choroidal fissure.

26. The choroid plexus in the lateral ventricle has a C-shaped configuration that parallels the fornix. It is attached along the choroidal fissure, a narrow cleft between the fornix and the thalamus , in the medial part of the body, atrium, and temporal horn . The choroidal fissure extends from the foramen of Monro along the medial wall of the body, atrium, and temporal horn to its inferior termination, the inferior choroidal point, located just behind the uncus and hippocampal head. The veins coursing in the walls of the lateral ventricles exit the ventricles by passing, in a subependymal location, through the margin of this fissure to reach the internal cerebral, basal, or great veins.

27. Frontal horn The medial group of veins in the frontal horn consists of the anterior septal veins, and the lateral group consists of the anterior caudate veins. The anterior septal veins are formed by tributaries from the deep white matter near the frontal pole, reach septum pellucidum and course over foramen of monro , enter the velum interpositum , and terminate in the internal cerebral vein. The anterior caudate veins are formed from small tributaries terminate near the foramen of Monro in the thalamostriate or thalamocaudate veins.

28. Body of the Lateral Ventricle The medial group of veins in the body is formed by the posterior septal veins, and the lateral group consists of the thalamostriate , thalamocaudate , and posterior caudate veins . Thalamostriate is the best known of the subependymal veins because it is the one most frequently seen on angiography. The angle formed by the junction of the thalamostriate and the internal cerebral veins at the thalamic tubercle, the venous angle , as seen on the lateral view of the cerebral angiogram, approximates the site of the foramen of Monro

29. Atrium and Occipital Horn Medial group of veins in the atrium and occipital horn consists of the medial atrial veins, and the lateral group is composed of the lateral atrial veins. Medial atrial veins drain forward on the medial wall of the atrium and occipital horn. They pass through the choroidal fissure or crus of the fornix and terminate within the velum interpositum or quadrigeminal cistern in the internal cerebral or basal veins or their tributaries.

30. Lateral atrial veins drain the anterior and lateral walls of the atrium and occipital horn and the adjacent part of the roof and floor . Pass through the choroidal fissure to reach the ambient or quadrigeminal cisterns. There they join the internal cerebral , basal, or great vein . Transverse hippocampal veins course medially across the collateral trigone and hippocampus on the floor of the temporal horn and penetrate the fimbria.

31. Temporal Horn The medial group of veins courses on the roof, and the lateral group of veins courses on the floor. The roof is drained predominantly by the inferior ventricular vein, with a lesser contribution from the amygdalar vein, and the floor is drained by the transverse hippocampal veins . The veins from the temporal horn join the basal vein or its tributaries.

32. Choroidal Veins Superior and inferior choroidal veins are the most consistent veins on the choroid plexus. The superior choroidal vein , the largest of the choroidal veins , runs forward on the choroid plexus in the body of the lateral ventricle and terminates near the foramen of Monro in the thalamostriate or internal cerebral veins or their tributaries . Inferior choroidal vein , the next most consistent choroidal vein, courses anteriorly in the temporal horn along the inferior end of the choroid plexus. The superior and inferior choroidal veins frequently anastomose through the veins draining the glomus of the choroid plexus.

33. Internal Cerebral Veins Paired, originate just behind the foramen of Monro and course posteriorly within the velum interpositum . The length of the internal cerebral vein varies from 19 to 35 mm (average, 30.2 ). They follow the gentle convex upward curve of the striae medullaris thalami and, further distally, as they course along the superolateral surface of the pineal body, they follow the concave upward curve of the inferior surface of the splenium .

34. The veins from the frontal horn, body, and part of the atrium terminate in the internal cerebral veins as they course through the velum interpositum . Veins draining the temporal horn drain into the segment of the basal vein coursing through the ambient and crural cisterns, V eins from the atrium drain into the segments of the basal, internal cerebral, and great veins coursing through the quadrigeminal cistern . The internal cerebral veins, as they course through the velum interpositum , receive tributaries from the thalamus, the fornix, and the walls of the third ventricle, in addition to tributaries from the walls of the lateral ventricle.

35. CISTERNAL GROUP drains the area beginning anteriorly in front of the third ventricle and extending laterally into the sylvian fissure and backward to include the walls of the chiasmatic , interpeduncular, crural , ambient , and quadrigeminal cisterns, divided into three regions depending on their relationship to the brainstem and tentorial incisura: an anterior incisural region located in front of the brainstem, a middle incisural region situated lateral to the brainstem, and a posterior incisural space located behind the brainstem. Major veins in the cisternal group are the basal and great veins.

36. The basal vein is formed below the anterior perforated substance by the union of veins draining the walls of the anterior incisural space. I t proceeds posteriorly between the midbrain and the temporal lobe to drain the walls of the middle incisural space, and terminates within the posterior incisural space by joining the internal cerebral or great vein. The anterior and middle incisural regions are drained, almost totally, by tributaries of the basal vein. The veins in the posterior incisural region join the internal cerebral and great veins, as well as the basal vein.

37. Anterior Incisural Region Located anterior to the brainstem and extends upward around the optic chiasm to the subcallosal area and laterally below the anterior perforated substance. The cortical areas bordering the anterior incisural region, which may also be drained by the basal vein, include the insula and the orbital surface of the frontal lobe . The insular veins, one of the major contributing groups to the first part of the basal vein. The major venous structure in the anterior incisural space is the anterior segment of the basal vein.

38. The anterior perforated substance, on which numerous veins converge to form the basal vein, is in the central part of the roof of the anterior incisural space . Segment begins at the union of the posterior orbitofrontal, superficial and deep sylvian , and uncal veins below the anterior perforated substance, and passes posteriorly to end where the peduncular vein joins the basal vein at the anterolateral part of the cerebral peduncle . Tributaries of this segment are the deep middle cerebral , anterior cerebral, insular, orbitofrontal, olfac tory , uncal , peduncular , and inferior striate veins.

39. Middle Incisural Space drained by the middle segment of the basal vein, is located between the midbrain and the temporal lobe. The major venous trunk in this space is the middle segment of the basal vein, which courses along the upper part of the cerebral peduncle and below the pulvinar to reach the posterior incisural space. the inferior ventricular vein, which drains the roof of the temporal horn ; The anterior longitudinal hippocampal vein, which courses anteriorly along the dentate gyrus toward the inferior choroidal point;

40. the anterior hippocampal vein, which originates on the uncus and the posterior portion of the amygdaloid nucleus and proceeds posteriorly along the anterior hippocampal sulcus to form a common stem with the inferior ventricular or anterior longitudinal hippocampal vein ; the lateral mesencephalic vein, which courses along the lateral mesencephalon; the temporal cortical veins from the posterior two-thirds of the uncus; The medial temporal veins from the adjacent part of the parahippocampal and occipitotemporal gyri

41. Posterior Incisural Region situated posterior to the midbrain and corresponds to the pineal region This space is occupied by the quadrigeminal cistern. The venous relationships in the posterior incisural region are the most complex in the cranium because the internal cerebral, basal, and great veins and many of their tributaries converge on this area . The internal cerebral veins exit the velum interpositum to reach the posterior incisural space, where they join to form the vein of Galen.

42. The posterior segment of the basal vein begins at the posterior margin of the ambient cistern, where the vein passes to the posterior margin of the midbrain to reach the quadrigeminal cistern, and it terminates in the internal cerebral or great veins . Tributaries Atrial veins posterior longitudinal hippocampal vein superior vermian vein, the largest vein from the infratentorial part of the posterior incisural space , tectal veins medial occipitotemporal veins , Thalamic veins

43. The deep thalamic veins are divided into anterior, superior, inferior, and posterior thalamic veins . The superior thalamic vein is the largest of the thalamic veins. The superficial thalamic veins course along the ventricular surface of the thalamus in a subependymal location and drain into the adjacent veins in the ventricle, velum interpositum , or basal cisterns . Superior Vermian Vein - which arises on the vermic surface forming the floor of the posterior incisural space and receives the superior hemispheric veins from the adjacent cerebellar surface and the vein of the cerebellomesencephalic fissure and empties into the great vein.

44. DISCUSSION AND OPERATIVE APPROACHES Venous phase of the cerebral angiogram may prove helpful in localizing expanding lesions by revealing poor filling and displacement and alteration in the direction of flow. The veins on the lateral surface are larger than those on the medial and inferior surfaces. The largest veins on the lateral surface are usually in the region of the central sulcus. The fact that sacrifice of the individual cortical veins only infrequently leads to venous infarction, hemorrhage , swelling , and neurological deficit is attributed to the diffuse anastomoses between the veins.

45. Obliteration of the superficial and deep bridging veins, including the great, basal, and internal cerebral veins, is inescapable in some operative approaches; however, the number of these veins and their branches to be sacrificed should be kept to a minimum because of the possible undesirable sequelae. Another option is to divide only a few of their small tributaries, which may allow the displacement of the main trunk out of the operative field. The increase in size of draining vein usually signifies that the vein drains a larger area than normal and increases the likelihood of ill effect if it is sacrificed.

46. The increase in size usually signifies that the vein drains a larger area than normal and increases the likelihood of ill effect if it is sacrificed . In removing a parasagittal tumor deep to these sinuses, the dura is opened along the edges of the sinus while preserving the sinus' proximal junction with the cortical veins and its distal junction with the superior sagittal sinus. The tumor is then separated from the lower margin of the meningeal sinus without sacrificing the sinus . The lacunae may extend along the medial extent of the hemisphere adjacent to the falx and as far as 3 cm laterally over the convexity. Parasagittal meningiomas usually arise from the arachnoid granulations in the lacunae and do not necessarily occlude the adjacent cortical veins.

47. These veins should be carefully separated from the deep margin of the tumor by micro-operative techniques, rather than obliterating them when they are exposed along the margin of the tumor . The corpus callosum may be reached in the area between the anterior and posterior frontal veins without sacrificing any bridging veins because there is frequently a several- centimeter segment of the superior sagittal sinus between the anterior and middle frontal veins or between the middle and posterior frontal veins where no tributaries join the superior sagittal sinus. Obliteration of the bridging veins to the superior sagittal sinus in the region of the precentral, central, or postcentral gyri frequently causes a contralateral hemiparesis that is more prominent in the lower than the upper extremity and is usually transient.

48. In the subfrontal approach, bridging veins are rarely encountered in the area between the frontal lobe and the orbital roof. The veins most commonly sacrificed in this approach are those along the medial part of the exposure, which drain into the anterior end of the superior sagittal sinus, and those on the lateral side of the exposure, which empty into the sphenoparietal and cavernous sinuses adjacent to the sphenoid ridge. Reaching lesions in the basal cisterns by the frontotemporal ( pterional ) and subtemporal approaches may require the sacrifice of one or more bridging veins entering the dual sinuses adjacent to the sphenoid ridge, which courses toward the cavernous sinus.

49. Obliteration of the superficial or deep sylvian veins along the sphenoid ridge may cause seizures and a facial palsy plus aphasia if the occlusion is on the left side. It may be possible to preserve the bridging veins entering the sinuses along the sphenoid ridge if the frontotemporal approach is entirely above the sphenoid ridge or if the subtemporal approach is entirely below the temporal pole. Further posteriorly under the temporal lobe, temporal, occipital, temporobasal , and occipitobasal veins and the vein of Labbé are encountered; their sacrifice causes some degree of venous infarction and edema of the temporal lobe.

50. references Rhotons 4 th edition