The Venous System

Question 1

How does the extracranial venous system accuses the sinuses

Answer 1

Via the ‘emissary’ vessels crossing the skull

Uncommon but potential route for infection

Question 2

Name the 3 types of intracranial veins

Where do they drain into

Answer 2

1. Superficial veins
2. Deep veins
3. Dural veins

Drain to the internal jugular bulb and vein

Question 3

Where do superficial cerebral veins drain to

Answer 3

Superior sagittal sinus

Question 4

Deep intracranial venous drainage

Answer 4

• 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

Question 5

What are venous sinuses

Answer 5

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

Question 6

Where are venous sinuses located

What is their function

What are they lined with

What empties into them

Where do they ultimately drain into

Answer 6

• 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

Question 7

Where does the superior sagittal sinus run

Where does it begin

Where does it end

Answer 7

• 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

Question 8

How does the inferior sagittal sinus compare to the superior

Where does it run

Where does it drain into

Answer 8

• 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

Question 9

Where do the superior sagittal and straight sinuses drain into the confluence of sinuses

Answer 9

At the internal occipital protuberance

Question 10

Where does blood go when it leaves the confluence

Answer 10

Travels laterally in both directions in the transverse sinues which run in the posterior margin of the tentorium cerebelli

Question 11

Where do the transverse sinuses (along with a network of other smaller venous sinuses - sphenoidal, clival) drain into

Answer 11

The sigmoid sinus which ultimately drains to the internal jugular bulb and vein located at the jugular foramen and returning blood to the heart

Question 12

Corresponding dural venous sinus associated with the falx cerebri

Answer 12

Superior sagittal

Inferior sagittal

Question 13

Corresponding dural venous sinus associated with the tentorium cerebelli

Answer 13

Transverse sinus - sigmoid

Question 14

Veins that drain the skull

Answer 14

Deploic veins

Question 15

What do emissary vessels supply

Answer 15

The venous sinuses

Question 16

Sub-ependymal veins drain the lateral and 3rd ventricles

Question 17

What do superficial veins traverse

Answer 17

Sub-arachnoid space

Mainly follow sulci

Question 18

Where do venous sinuses reside

Answer 18

Between the periosteal and meningeal sublayers of the dura mater

Question 19

Where is the superior sagittal sinus

Answer 19

At the superior most point of the longitudinal fissure

Runs anterior to posterior - superior portion of falx cerebri

Question 20

Where does the inferior sagittal sinus run

Answer 20

Inside the inferior border of the falx cerebri

Superior to the corpus callosum

Question 21

Where does the ISS drain

Answer 21

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)

Question 22

Where does the SSS drain into

Answer 22

The confluence of sinuses

Question 23

Where does blood go after the confluence of sinuses

Answer 23

Laterally into transverse sinuses

Question 24

Where does blood go from the sigmoid sinus

Answer 24

Internal jugular bulb and vein

Question 25

Tentorial notch

Answer 25

Gap through which the brainstem passes

Question 26

Emissary vessels function

Answer 26

Bring extracranial blood into the intracranial space specifically to the venous sinuses (potential route for infection)