1. CEREBRAVASCULAR ANATOMY VENOUS SYSTEM&PATHOLOGIES
Eylül YERAL

2. The cerebral venous system, unlike the majority of the rest of the body, does not even remotely follow the cerebral arterial system
The cortical veins lie superficially, unlike cortical arteries, and are adherent to the deep surface of the arachnoid so that they keep the sulci open
Cortical veins then drain to the nearest dural venous sinuses. Such as the superior sagittal sinus and the straight sinus to the the confluence of sinuses, then to the transverse sinuses, sigmoid sinuses and internal jugular veins.

3. The whole system may be divided into some sections: Cerebral Veins
superficial
deep
Dural venous sinuses

4. The cerebral veins drain the brain parenchyma and are located in the subarachnoid space. They pierce the meninges and drain further into the cranial venous sinuses.
The cerebral veins lack muscular tissue and valves. 
-superficial (cortical) cerebral veins
-deep (subependymal) cerebral veins

5. Superficial Venous System
Comprised of the sagittal sinuses and cortical veins. 
The cortical veins course along the cortical sulci, drain the cortex and some of the adjacent white matter.
Can be subdivided into superior, middle and inferior groups. 
Important veins of superficial cerebral venous system;
-Superficial middle cerebral vein
-Superior anastomotic vein of Trolard
-Vein of Labbé

8. Superficial Middle Cerebral Vein
Runs along the lateral sulcus-also known as Sylvian Vein
Drains into the sphenoparietal sinus or cavernous sinus
Connected with superior sagittal sinus via great anastomotic vein of Trolard, and with transverse sinus via posterior anastomotic vein of Labbé.

10. Vein Of Labbé
Largest channel that crosses the temporal lobe between the Sylvian fissure and the transverse sinus 
Surgically it is of importance in planning temporal lobectomy for refractory temporal epilepsy, as the vein should be preserved, often requiring some cortical tissue to be left behind. This is especially the case in the 10% of cases where the vein is located anteriorly. 

11. Deep Cerebral Veins
Drain deeper parts of hemispheres, basal nuclei, internal capsule, diencephalon and choroid plexus
Consists of the lateral sinuses, sigmoid sinuses, straight sinus and draining deep cerebral veins (subependymal and medullary veins)
-Medullary veins are numerous and originate 1-2 cm below cortical gray matter and pass through deep medullary white matter and drain into subependymal veins. 
-Subependymal veins receive medullary veins and aggregate into greater tributaries, mainly into septal veins, thalamostriate veins, internal cerebral veins, basal vein of Rosenthal and vein of Galen.

13. Vein Of Galen
Formed by the union of the two internal cerebral veins and basal veins of Rosenthal
 Drain into the confluence of the inferior sagittal sinus and the anterior extremity of the straight sinus

14. Vein Of Galen Malformation
The most frequent arteriovenous malformation in neonates.
Results from an aneurysmal malformation with an arteriovenous shunting of blood
Develops during weeks 6-11 of fetal development as a persistent embryonic prosencephalic vein of Markowski
Typically result in high-output congestive heart failure or may present with developmental delay, hydrocephalus, and seizures.(vary with the type of malformation)
Has been associated with capillary malformation-arteriovenous malformation (CM-AVM), which is a newly recognized autosomal dominant disorder, caused by mutations in the RASA1 gene in 6 families

16. Presentation commonly with high output cardiac failure in neonates while mostly hydrocephalus in infants and children
Angiography:gold std
Classification
Lasjaunias classification:
Choroidal: tend to present earlier (neonate) with more severe shunts&high output cardiac failure
Mural: present later (infant) and typically with hydrocephalus. Fewer fistulas-high outflow restriction
-Yasargil Classification
type I: small pure cisternal fistula between the vein of Galen and either the pericallosal arteries (anterior or posterior) or posterior cerebral artery
type II: multiple fistulous communications between the vein of Galen and the thalamoperforating vessels
type III: high flow mixed type I and II
type IV: parenchymal arteriovenous malformation (AVM) with drainage into the vein of Galen

18. Tx&Prognosis Arterial feeder and fistula occlusion
Transtorcular or transvenous embolisation of the dilated vein
Prognosis  is largely determined by the presence or absence of cardiac failure.  Thus choroidal types and those presenting in the neonatal period do poorly.

19. Dural Venous Sinuses
Venous channels located intracranially between the two layers of dura mater (endosteal layer and meningeal layer)
Unlike other veins in the body they run alone, not parallel to arteries
They are valveless, allowing for bidirectional blood flow in intracranial veins.
Together the dural venous sinuses form the major drainage pathways from the brain, predominantly to the internal jugular veins.

20. Dural Venous Sinuses transverse sinus sigmoid sinus
Paired
Unpaired
transverse sinus
sigmoid sinus
superior petrosal sinus
inferior petrosal sinus
cavernous sinus
sphenoparietal sinus
basilar venous plexus
superior sagittal sinus
inferior sagittal sinus
straight sinus
occipital sinus
intercavernous sinus

24. Cavernous Sinuses
Located on either side of the pituitary fossa and body of the sphenoid bone between the endosteal and meningeal layers of the dura. (lateral and superior to the sphenoid sinus and are immediately posterior to the optic chiasm)
Boundaries:
Roof: fold of dura mater attached to the anterior and middle clinoid processes
Anterior wall:medial end of the superior orbital fissure
Posterior:petrous apex
Medial: endosteum of body of the sphenoid bone
Lateral:dura mater from the ridge of the roof to the floor of the middle cranial fossa
Floor: greater wing of sphenoid bone

25. Cavernous Sinus
Receive venous blood from the facial veins (via the superior and inferior ophthalmic veins) as well as the sphenoid and middle cerebral veins(-inferior &superior petrosal sinuses-sigmoid-ijv)
Because of this complex is made of valveless veins, blood can flow in any direction depending on the prevailing pressure gradients. Since the cavernous sinuses receive blood via this distribution, infections of the face including the nose, tonsils, and orbits can spread easily by this route.

26. Cavernous Sinus

27. Cavernous Sinus Thrombosis
Rare, high mortality&morbidity
Etiology,
Infections:
-Most commonly results from contiguous spread of infection from the sinuses or middle third of the face(furuncle), or less commonly dental abscess or orbital cellulitis
-Staph. Aureus (%55)
Sinus compression, e.g. trauma, tumour
Procoagulable conditions, e.g. Protein C/S deficiency, OCP use, malignancy
Idiopathic (25%)
Headache(m.common)
focal cranial nerve abnormalities
periorbital edema and visual disturbances

28. Cavernous Malformations
Mostly single lesions
 Multiple lesions may be familial and screening of family members may be indicated (familial multiple cavernous malformation syndrome)
Along with capillary telangiectasias, are commonly seen following cerebral radiotherapy
Mostly asymptomatic- or hemorrhage and seizures
Composed of a "mulberry-like" cluster of dilated thin-walled capillaries, with surrounding hemosiderin.(Unlike AVMs,there is no normal brain between the interstices of these lesions. )
%80 supratentorial
Characteristic popcorn appearance in MRI
Symptomatic lesions should, when possible, be resected and complete resection is curative 

32. Cerebral Venous Angioma(DVA)
A congenital malformation of veins which drain normal brain
Most common cerebral vascular malformation
Characterised by the caput medusae sign(collection of dilated medullary veins converge in an enlarged transcortical or subependymal collector vein) in angiography. The appearance has also been likened to a palm tree
Usually incidental findings but patients can present with intracranial haemorrhage(1-5%) and also with ischaemic stroke and epilepsy.
Most common location: frontoparietal region (36-64%)
%75 solitory lesions but %20 of cases are associated with cavernous malformations and are referred to as mixed vascular malformations (MVM)

35. References
Handbook of Neurosurgery (ebook), 7th Edition, by Mark S. Greenberg