The Venous System Flashcards
How does the extracranial venous system accuses the sinuses
Via the ‘emissary’ vessels crossing the skull
Uncommon but potential route for infection
Name the 3 types of intracranial veins
Where do they drain into
- Superficial veins
- Deep veins
- Dural veins
Drain to the internal jugular bulb and vein
Where do superficial cerebral veins drain to
Superior sagittal sinus
Deep intracranial venous drainage
- Internal cerebral veins - bilateral, formed by the union of the posterior and anterior terminal veins
- Great cerebral vein (of Galen), union of the internal cerebral veins - most common location for malformation of infants and foetuses, drains to the straight venous sinus
What are venous sinuses
A series of large veins that reside between the dural sublayers and ultimately drain blood to the internal jugular vein
** CSF drains into these via arachnoid granulations as the end of the CSF route where it then merges with the venous blood
Where are venous sinuses located
What is their function
What are they lined with
What empties into them
Where do they ultimately drain into
- Large vessels that reside between the periosteal and meningeal sub layers of the dura mater
- Contain and transport venous blood
- Endothelial lined spaces
- Large veins from the surface of the brain empty into them
- CSF arrives into them as well via the arachnoid granulations
- Ultimately drain to the internal jugular veins
Where does the superior sagittal sinus run
Where does it begin
Where does it end
- Runs along the superior border of the falx cerebri
- Begins at the crista gali of the ethmoid bone
- Ends near the internal occipital protuberance at the CONFLUENCE OF THE SINUSES
How does the inferior sagittal sinus compare to the superior
Where does it run
Where does it drain into
- Inferior sagittal sinus is smaller and shorter than the superior
- Runs inside the inferior border of the falx cerebri
- Drains into the straight sinus which runs along the midline joint between the falx cerebri and the tentorium cerebelli to drain into the confluence of the sinuses
Where do the superior sagittal and straight sinuses drain into the confluence of sinuses
At the internal occipital protuberance
Where does blood go when it leaves the confluence
Travels laterally in both directions in the transverse sinues which run in the posterior margin of the tentorium cerebelli
Where do the transverse sinuses (along with a network of other smaller venous sinuses - sphenoidal, clival) drain into
The sigmoid sinus which ultimately drains to the internal jugular bulb and vein located at the jugular foramen and returning blood to the heart
Corresponding dural venous sinus associated with the falx cerebri
Superior sagittal
Inferior sagittal
Corresponding dural venous sinus associated with the tentorium cerebelli
Transverse sinus - sigmoid
Veins that drain the skull
Deploic veins
What do emissary vessels supply
The venous sinuses
Sub-ependymal veins drain the lateral and 3rd ventricles
What do superficial veins traverse
Sub-arachnoid space
Mainly follow sulci
Where do venous sinuses reside
Between the periosteal and meningeal sublayers of the dura mater
Where is the superior sagittal sinus
At the superior most point of the longitudinal fissure
Runs anterior to posterior - superior portion of falx cerebri
Where does the inferior sagittal sinus run
Inside the inferior border of the falx cerebri
Superior to the corpus callosum
Where does the ISS drain
Where the falx cerebri meets tentorium cerebelli
* falco-tentorial apex
Great vein of gallen also drains at this junction
-> drain into straight sinus (runs from apex of tentorium cerebelli to the confluence of sinuses)
Where does the SSS drain into
The confluence of sinuses
Where does blood go after the confluence of sinuses
Laterally into transverse sinuses
Where does blood go from the sigmoid sinus
Internal jugular bulb and vein
Tentorial notch
Gap through which the brainstem passes
Emissary vessels function
Bring extracranial blood into the intracranial space specifically to the venous sinuses (potential route for infection)
