NEUROANATOMY - Venous Sinuses Flashcards
Where does the superior sagittal sinus lie?
Between the inner dura and outer endosteum and runs above the falx cerebri
What is the route of the superior sagittal sinus?
Begins above foramen caecum, runs between layers of falx cerebi, and becomes continuous with transverse sinus (dilation at this point is called confluence of sinuses).
What does the superior sagittal sinus contain?
Contains arachnoid villi through which CSF is absorbed into the bloodstream
What is the route of the straight sinus?
Located where falx cerebri meets tentorium cerebelli.
Formed from inferior sagittal sinus and great cerebral vein, it runs backwards to drain into the transverse sinus at the internal occipital protuberance.
What is the route of the inferior sagittal sinus?
At the lower margin of the falx cerebri, it runs backwards to join the great cerebral vein to form the straight sinus
What are the paired venous sinuses? (6) What are the unpaired venous sinuses? (5)
UnPaired (midline):
* Superior sagittal sinus
* Inferior sagittal sinus
* Straight sinus
* Occipital sinus
* Intercavernous sinus
Paired
1. Transverse
2. Sigmoid
3. Cavernous
4. Superior Petrosal
5. Inferior Petrosal
What is the route of the transverse sinus?
Right and left transverse sinus formed at the confluence from superior/inferior sagittal and occipital. Pass along border of tentorium cerebelli along inner surface of occipital bone –> at border of temporal bone (petrous part) becomes the sigmoid sinus.
What is the difference between the right and left transverse sinus?
Right is typically continuous with superior sagittal and left is continuous with the straight sinus.
What is the route of the occipital sinus?
smallest venous sinus and situated at inner surface of occipital bone. Forms at edge of foramen magnum and drains into confluence of sinuses at internal occipital protuberance.
What is the route of the sigmoid sinus?
It is in close proximity to which type of air cells?
Continuation of transverse sinus at petrous part/mastoid process of temporal bone.
Take an S shaped course along temporal and occipital bones and pass through jugular foramen to become internal jugular veins
Close proximity to mastoid air cells, so infection in the mastoid region can cause thrombosis here.
What is the route of the occipital sinus?
Small sinus attached at the margin of falx cerebeli and drains into the confluence of sinuses
Where is the cavernous sinus situated?
Middle cranial fossa within the body of the sphenod bone and sella turcica. Extends from superior orbital fissure anteriorly to apex of temporal bone posteriorly.
What does the cavernous sinus drain from and then drain into?
Drains from superior and inferior ophthalmic vein, inferior and superficial middle cerebral vein and sphenoparietal sinus and drains into superior and inferior petrosal sinuses (posteriorly) and pterygoid plexus (inferiorly)
What is the intercavernous sinus?
Connects the two cavernous sinuses - usually two channels either side of the pituitary stalk.
What are the borders of the cavernous sinus?
Anterior? Posterior? Medial? Lateral? Roof? Floor?
Anterior: SOF
Posterior: Petrous temporal bone/sphenoid air sinus.
Medial: Body of sphenoid bone/sphenoid sinus
Lateral: Meningeal layer of dura mater
Roof: Meningeal layer of dura mater
Floor: Endosteal layer of dura mater
What structures run across the floor (within) of the cavernous sinus? (2)
What structures pass through the lateral wall of the cavernous sinus? (4)
CAT. 1. Internal carotid with sympathetic plexus
2. Abducents nerve (VI)
Lateral wall: OTOM
1. Oculomotor (III)
2. Trochlear (IV)
3. Ophthalmic (VI)
4. Maxillary (VII)
What is the route of the superior and inferior petrosal sinuses?
Start at posterior border of cavernous sinus.
passes along surface of temporal bone and empties into transverse sinus.
Diagram of venous sinus flow.
