Intracranial Venous System
- Superficial cortical veins are thin-walled, valveless, and traverse the subarachnoid space within the cerebral sulci
- 8-12 smaller cortical veins over hemispheres
- Dominant superior anastomotic vein of Trolard
- Variable superficial middle cerebral veins
- Dominant middle anastomotic vein of Labbé
- Inferior: middle cerebral veins, basal vein of Rosenthal
- Medullary veins
- Small, linear venous branches originating in the subcortical white matter
- Course towards ventricles, terminate in subependymal veins
- Subependymal veins
- Along the margins of the ventricles
- Septal veins
- Course posteriorly along septum pellucidum
- Join with transverse sinus to form internal cerebral veins at interventricular foramen
- Thalamostriate veins
- Receive caudate veins that course anteriorly between caudate nucleus, thalamus
- Curve over caudate nuclei
- Terminate at interventricular foramen (of Monro) by uniting with septal veins to form internal cerebral veins
- Internal cerebral veins
- Deep paired paramedian veins
- Course posteriorly in cavum veli interpositi
- Terminate in rostral quadrigeminal cistern by uniting with the basal veins of Rosenthal to form vein of Galen
- Formed by thalamostriate and septal veins
- Great cerebral vein of Galen
- Short, U-shaped midline vein formed from union of internal cerebral veins, basal veins of Rosenthal
- Curves posteriorly and superiorly under corpus callosum splenium in quadrigeminal cistern
- Unites with inferior sagittal sinus at falcotentorial apex to form straight sinus
- Brainstem/posterior fossa veins
- Superior (galenic)
- Anterior (petrosal)
- Posterior (tentorial)
Dural venous sinuses
Endothelial-lined venous conduits encased within dural reflections
- Outer (periosteal) and inner (meningeal) dural layers
- Valveless, however can be complex
- Fenestrated, septated, and/or multi-channeled
- Contain arachnoid granulations and arachnoid villi
- Extension of arachnoid through dural wall into lumen of venous sinus
- Cerebrospinal fluid (CSF) resorption into venous circulation
- CSF-equivalent filling defects in dural sinuses
- Can be large and irregular, pitfall for dural venous sinus thrombosis
- Receive venous blood from supratentorial superficial (cortical) veins and deep (subependymal) veins
- Variable parallel conduits with extracranial veins via diploic calvarial veins
- Superior sagittal sinus
- Curvilinear sinus and coursing typically along the inner medial calvarium.
- Originates from the ascending frontal veins, anteriorly; courses posteriorly in midline at junction of the falx cerebri with the calvarium.
- Collects superficial cortical veins and increases in diameter as it courses posteriorly.
- Terminates in the torcula, at the falcotentorial apex, joining with vein of Galen to form straight sinus.
- Straight sinus
- Runs from falcotentorial apex posteroinferiorly to the sinus confluence
- Receives tributaries from the falx cereberi, the tentorium, and cerebral hemispheres.
- Torcular Herophili (also: torcula, venous sinus confluence)
- Formed by the union of the superior sagittal sinus, straight sinus, and transverse sinuses with highly variable interconnections and often asymmetric, right commonly larger than left.
- Contained between the attachment of tentorial leaves to the calvarium.
- Can extend laterally to posterior border of petrous temporal bone and receive tributaries from the tentorium, cerebellum, and inferior temporal/occipital lobes.
- Transverse-Sigmoid sinuses
- Sigmoid sinus is the anteroinferior continuation of the transverse sinus.
- Sigmoid sinuses terminate by becoming the internal jugular veins at the skull base.
- Cavernous sinuses
- Complex trabeculated venous compartment along the sides of the sella turcica, extending from the superior orbital fissure anteriorly to the clivus and petrous apex posteriorly. Important tributaries to the cavernous sinuses include the ophthalmic veins and sphenoparietal sinus. Each cavernous sinus communicates inferiorly with the pterygoid venous plexus, medially with the intercavernous sinus to the contralateral cavernous sinus, and posteriorly with the superior and inferior petrosal sinus, and clival venous plexus.
- Important contents
- C4 segment of the ICA
- CN VI
- Enters the dura mater through Dorello canal
- Traverses along the inferolateral aspect of the cavernous internal carotid artery
- CN III, IV, V1 and V2
- Travel within lateral dural wall
- Superior petrosal sinus
- The superior petrosal sinus courses along the petrous ridge from the cavernous sinus to the sigmoid sinus
- Inferior petrosal sinus
- The inferior petrosal sinus courses along the petrooccipital fissure from the clival venous plexus to the jugular bulb at the skull base.
- Sphenoparietal sinus
- The sphenoparietal sinus courses along the margin of the lesser sphenoid wing from the Sylvian fissure to cavernous sinus or inferior petrosal sinus.
- Occipital sinus
- Usually the smallest dural sinus, the occipital sinus arises from the foramen magnum, courses along the midline posterior fossa and terminates at the torcula.
- Clival venous plexus
- The clival venous plexus is located along the clivus from dorsum sellae to foramen magnum.
- Notable Normal Variants
- Variations are the rule, not the exception
- Superior sagittal sinus
- Absent anterior superior sagittal sinus (may begin posteriorly near coronal suture)
- Parasagittal course, drainage to transverse sinus directly
- Transverse-Sigmoid sinuses
- Absence or hypoplasia of part or all of one transverse sinus
Figure 1: Lateral DSA of the intracranial venous structures.
Figure 2: Detailed lateral view DSA of the posterior intracranial venous structures.
Figure 3: Frontal view DSA of the left intracranial venous structures.
- Variable size
- Variable configuration
- Jugular diverticulum
- Dehiscent jugular bulb
- “Vein of Galen” malformation
- Primitive median prosencephalic vein persists as outlet for diencephalic, choroidal venous drainage
- Associated with abnormal arteriovenous shunt
- Associated persistent embryonic falcine sinus
- High position of the torcula (Lambdoid-torcular inversion) with Dandy-Walker spectrum
The cerebral venous system is highly variable, but can be conceptualized as having 3 dominant patterns of superficial, deep supratentorial, and deep infratentorial drainage pathways.
The superficial drainage of the brain is radial or centrifugally from the Sylvian fissures by way of cortical and dominant anastomotic venous branches:
- Laterally, by the superficial vein of Labbé which drains into the transverse sinus
- Superiorly, by the superior cerebral veins and superficial vein of Trolard which empties into the superior sagittal sinus
- Internally, by the superficial middle cerebral vein which drains from the Sylvian fissure into the cavernous sinus.
- The vein of Labbé may arise from the posterior extent of the superficial middle cerebral vein.
Deep Supratentorial Drainage
The deep venous drainage of the supratentorial cerebrum converges on the internal cerebral veins and the vein of Galen.
- Medullary veins radiate inferiorly from the superficial white matter to drain to the subependymal and thalamostriate veins.
- Deep veins of central and nuclear regions (Choroidal, caudate, terminal, lateral, atrial, and ventricular veins) drain to the medial subependymal septal vein and the lateral subependymal thalamostriate veins which unite with the internal cerebral veins.
- The internal cerebral veins commonly arise at the foramen of Monro and runs on either side of the roof of the third ventricle.
- The internal cerebral veins unite to form the vein of Galen.
- The vein of Galen drains to the straight sinus.
Deep Infratentorial Drainage
The anatomy of the posterior fossa venous drainage is complex.
- Superior vermian, posterior pericallosal, mesencephalic, and internal occipital veins drain into the vein of Galen which also receives drainage from the basal vein of Rosenthal, which in turn receives venous supply from the insular lateral mesencephalic veins (and deep middle cerebral and anterior cerebral veins of the cerebrum).
- The vein of Galen and inferior sagittal sinus drain to the straight sinus, which in turn drains into the torcula along with the superior sagittal sinus
- The torcula drains into the paired transverse sinuses, which also receive drainage from the superior petrosal sinuses, diploic veins, and lateral cerebellar veins. The transverse sinuses course laterally in the leaves of the tentorium and continue as the sigmoid sinuses, which also drain the occipital sinuses.
- The sigmoid sinus terminates as the internal jugular vein
- The inferior vermian veins and superior hemispheric veins drain into the straight sinus.
- Each transverse sinus receives blood from the inferior and superior cerebellar hemispheric venous system.
- The deep middle cerebral vein courses deep in the Sylvian fissure, and it meets with the anterior cerebral vein to form the basal vein of Rosenthal arising along the brain stem. The basal vein of Rosenthal receives blood from the anterior pontomesencephalic vein in front of the brain stem, the lateral mesencephalic veins, and the precentral cerebellar vein.
- Anterior venous drainage converges on the cavernous sinuses. These venous channels receive blood from superior and inferior ophthalmic veins, the sphenoparietal sinus, and the superficial middle cerebral vein. The cavernous sinus communicates via
- An extensive network across midline to the opposite cavernous sinus via the intercavernous sinus
- Posteriorly via the superior petrosal sinus to the transverse sinuses just before the latter dive inferiorly to the sigmoid sinus
- Inferiorly into the inferior petrosal sinuses, which subsequently drain directly to the jugular bulbs. The inferior petrosal sinus also drains the internal auditory canal venous system
Venous vascular territories
- Highly variable compared to arterial territories
- Cortical venous drainage is ideally radial, centrifugal from the Sylvian regions
- Cerebral cortex and subcortical white matter drained by cortical veins to superior sagittal sinus
- Posterior and inferior temporal lobe, temporoparietal region drained by vein of Labbé to transverse sinus
- Anterior temporal lobe, insular cortex, parenchyma around Sylvian fissure drained by sphenoparietal sinus to cavernous sinus
- Central and deep white matter, basal ganglia drained by medullary and subependymal veins to internal cerebral veins, vein of Galen, straight sinus
- Medial temporal lobe drainage via basal vein of Rosenthal to vein of Galen
Contributors: Daniel Murph, MD; Andrew DeNardo, MD; John Scott, MD and Daniel Sahlein, MD
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