Venous Supply to Orbit & Eye Flashcards
What do the vortex veins provide drainage for?
Provide drainage for the UVEAL tract (choroid, ciliary body & iris).
Where do the vortex veins pierce the sclera?
Obliquely and open posterior to the equator
What are the superior vortex veins and what do the superior vortex veins drain into?
Lateral & Medial
Drain into the superior ophthalmic vein, muscular or lacrimal branches
What are the inferior vortex veins and what do the inferior vortex veins drain into?
Lateral & Medial
Drain into the inferior ophthalmic vein
What does the superior ophthalmic vein drain?
Main venous channel for the superior orbit
Where does the superior ophthalmic vein drain into?
The cavernous sinus
Where does the superior ophthalmic vein begin?
Inner angle of the orbit
What course does the superior ophthalmic vein follow?
The Ophthalmic artery, passing between the 2 heads of the lateral rectus muscle, through the medial SOF and ends at the cavernous sinus
Where does the Inferior Ophthalmic Vein begin?
At the floor and medial wall of the orbit
How does the Inferior Ophthalmic vein travel?
Travels backward and divides into 2 branches
What does the inferior ophthalmic vein drain?
Channel for inferior drainage
Where are the dural venous sinuses?
Between the periosteal (under Dura mater) and meningeal (superior to Arachnoid mater) layers of the dura. It’s between these two layers of outer dura mater that the venous sinuses run
What veins drain into the dural venous sinuses?
Superficial veins from the brains surface run into these sinuses such as the superficial cortical veins and into the superior sagittal sinus to eventually reach the internal jugular vein. CSF is drained into the venous sinuses through arachnoid granulations. .
Where does the dural venous sinus system drain into?
The internal jugular vein which returns blood to the right side of the heart through the branchothalamic veins on either side to the vena cava.
What are the 5 main unpaired dural venous sinuses along the sagittal midline of the brain?
1) Superior sagittal sinus
2) Inferior sagittal sinus
3) Straight sinus
4) Occipital sinus
5) Intercavernous sinuses
What are the 5 main paired dural venous sinuses along the sagittal midline of the brain?
1) Transverse Sinuses
2) Sigmoid Sinuses
3) Cavernous Sinuses
4) Superior Petrosal Sinuses
5) Inferior Petrosal Sinuses
What is the superior sagittal sinus? Where does it receive venous blood from?
The largest dural venous sinus. Receives venous blood from many tributaries of the cerebral hemisphere and superficial cortical veins.
What do the superior cerebral veins feed into?
Superior sagittal sinus
Where does the superior sagittal sinus extend from?
Frontal crest of the frontal bone (foramen caecum) to the internal occipital protuberance of the occipital love
What does the superior sagittal sinus combine with to form the confluence of sinuses?
Superior sagittal sinus, straight sinus, occipital sinus and transverse sinuses
What forms the confluence of sinuses?
Superior sagittal sinus, straight sinus, occipital sinus and transverse sinuses
Where does the superior sagittal sinus reside?
Within the superior border of the falx cerebri
Where is the inferior sagittal sinus?
Inferior margin of the falx cerebri
What does the Inferior Sagittal Sinus drain?
Venous drainage from falx cerebri and numerous small venous veins that drain into the medial surface of the cerebral hemispheres
Posteriorly, what does the inferior sagittal sinus combine with to form the straight sinus?
Great Cerebral Vein (“Vein of Galen”)
What forms the Straight Sinus?
Inferior Sagittal Sinus & the Great Cerebral Veins (“Vein of Galen”)
Where does the Inferior Sagittal Sinus drain into?
Straight Sinus
Where is the straight sinus located?
Where the falx cerebri meets the tentorium cerebelli
As the straight sinus continues posteriorly, where does it receive venous drainage from?
Superior Cerebellar Vein before joining the confluence of sinuses
What is the Great Cerebral Vein (“Vein of Galen”)?
Deep cerebral vein that feeds into the straight sinus.
What form the Great Cerebral Vein (“Vein of Galen”)?
2 Internal cerebral veins and join the Basal vein of Rosenthal to form the Vein of Galen
What does the straight sinus drain into?
Confluence of sinuses (Torcular Horophili)
What is the Torcular Horophili?
Confluence of Sinuses
How does the straight sinus run?
Posteriorly and inferiorly
Where is the Occipital sinus?
On the inner surface of the occipital bone within the falx cerebri
What’s the smallest of the venous sinuses?
Occipital Sinus
Where does the Occipital Sinus extend from?
Foramen magnum to the occipital protuberance
Where does the occipital sinus drain?
Confluence of sinuses at the occipital protuberance
What are the Intercavernous sinuses?
Sinus that provides a connection between the left and right paired cavernous sinuses consisting of anterior and posterior channels that lie either side of the pituitary stalk
What are the transverse sinuses also known as?
Lateral sinuses (paired left and right)
Where are the transverse sinuses formed?
Confluence of sinuses
At what point do the transverse sinuses become the sigmoid sinuses?
As they approach the petrous part of the temporal bone
Where does transverse sinuses drain into?
The Sigmoid Sinuses
Which sinus contains a bigger sinus on either the left or right due to asymmetrical drainage of blood?
Transverse sinuses
Why might one transverse sinus be bigger than its paired sinus?
Due to asymmetrical drainage of blood. The larger is considered the “dominant” sinus
Where does the transverse sinus extend?
Extend laterally from the confluence of sinuses
Where are the Sigmoid Sinuses?
They’re a continuation of the transverse sinuses at the internal surface of the petrous part of the temporal bone
Where do the Sigmoid sinuses run?
Along the temporal and occipital bones
What do the Sigmoid Sinuses become? and where?
When the sigmoid sinuses pass through the jugular foramen they become the internal jugular veins.
Where are the cavernous sinuses?
Sphenoid bone of the skull base
Where does the cavernous sinus receive drainage from?
Ophthalmic vein, superficial middle cerebral vein and sphenoparietal sinus
What drains the cavernous sinuses?
Superior and inferior petrosal sinuses
What is the cavernous sinus?
Large venous plexus either side of the sella turcica (concave in basisphenoid containing the pituitary gland). Anterior border is SOF and posterior border petrous apex of temporal bone.
Where do the petrosal sinuses drain into?
Return venous blood to the transverse sinuses and internal jugular veins respectively.
What are petrosal sinuses?
The smallest sinuses that are located in relation to the petrel parts of the temporal bones. Paired and have superior and inferior branches.
What does the superior petrosal sinus drain? and into what?
The cavernous sinuses into the transverse sinuses. Also some from inferior cerebral vein, cerebellar veins and the labyrinth vein
What does the inferior petrosal sinus drain?
Assists in the drainage of the cavernous sinuses
Where do the inferior petrosal sinuses drain into?
Internal jugular veins at the jugular foramen
How are the left and right inferior petrosal sinuses connected?
Basilar venous plexus
What does the basilar venous plexus do?
It interconnects the left and right inferior petrosal sinuses and also communicates inferiorly with the vertebral venous plexus.
What is your mnemonic for remembering the unpaired and paired venous sinuses?
Sit In Sweden Or In Turkey, Singing Carols, Santa Incoming Presents
What are the unpaired and paired venous sinuses?
Sit - Superior Sagittal
In - Inferior Sagittal
Sweden - Straight
Or - Occipital
In - Intercaverous
Turkey - Transverse
Singing - Sigmoid
Carols - Cavernous
Santa - Superior Petrosal
Incoming Presents - Inferior Petrosal
