hello all this is dr. Alsup and in this session we will be discussing the dural
venous sinuses recall that these venous sinuses are endothelial lined spaces that form in areas
where that meningeal dura will reflect away from the periosteal dura or the dura this closest to
the bone there are similar to veins and that they will drain mostly deoxygenated blood back towards
the heart but the composition of the walls of the venous sinuses are certainly different most
sinuses are draining toward the internal jugular vein so almost all roads head inferior so let's
get started starting with the longest and one of the most prominent will be your superior sagittal
sinus and you can see it visible here through the dura in this anterior superior view you can see
some of those arachnoid granulations associated with the lacunae of the superior sagittal sinus
as well quite prominent in this particular image you can also see that the superior sagittal sinus
runs along the length of the superior falx cerebri and note that in this particular dissection the
sinus has been open so that's why it looks so dark here so running the length of the falx
cerebri it ultimately drains into the confluence of sinuses which is going to be located superior
lateral to the internal occipital protuberance so recall that the falx cerebri actually attaches to
the internal occipital protuberance so that makes sense that it's going to drain right around there
so that confluence which we'll talk a little bit more about it's going to be around this area here
all right same image but let's add in a few other sinuses the inferior sagittal sinus will traverse
the inferior concave border of the falx cerebri so it's a bit more difficult to see it hasn't been
open like we have here on the superior sagittal sinus you can see a little bit of the blue back
in this area here but anything that's along this free border of the falx cerebri would become part
of the inferior sagittal sinus it will join with the great cerebral vein which you can see a little
bit right here to form the straight sinus which I am outlining about where that would be located
there the straight sinus runs along the line of attachment of the Falx cerebri to the tentorium
cerebelli so that's your Falx cerebri that we've been discussing in your tentorium cerebelli
is here and where they meet up the straight sinus will run it like the superior sagittal sinus will
drain into the confluence of sinuses so let's talk about that confluence you can see right
around this area here you see quite a bit more blue the the confluence of sinus is what is going
to be forming that right there it is exactly what it sounds like it's a large area where multiple
things in this case venous sinuses are going to drain three major sinuses drain here so that's
superior sagittal sinus the straight sinus and the smaller occipital sinus which will run in the falx
cerebelli as mentioned before this is typically located superior lateral to the internal occipital
protuberance and the confluence will then flow bilaterally into pair transverse sinuses so you'll
have a right and a left transverse sinus but we'll see that a bit better in a moment now looking at a
superior view note that the falx cerebri has mostly been removed but the tentorium cerebelli is still
present so here's your tentorium cerebelli still in this particular image and let's locate some of
the sinuses we just discussed in this particular view so here is the straight sinus you would have
it a little bit on the other side as well the straight sinus you can see even a little bit of
the great cerebral vein right here the confluence of sinuses is located about right here and you'll
have an extension a little bit over in this region as well you can see that it's nice and large it's
going to be particularly blue in this area and it's in this image that we're really starting
to get a nice view of those transverse sinuses so recall that the confluence of sinuses will drain
into the transverse sinuses they're going to move laterally along the occipital bone as indicated
by the grooves of the transverse sinuses on the actual bone moving anteriorly we can begin to
conceptualize the expansive cavernous sinuses these paired sinuses are going to be lateral
to the sella turcica region so this is the sella turcica region so it's going to be lateral to that
they are also going to extend between the superior orbital fissure which would be up in this region
so from the superior orbital fissures back to around the apices of the the petrous parts of
the temporal bone so you can see that it's going to be around this region right here that's going
to be part of the cavernous sinus so very expansive venous sinuses here now numerous
neurovascular structural structures will traverse the cavernous sinuses but we will discuss that in
more detail in later sessions because we would really need to do a deeper dive and remove some
of the dura to see those structures better now just kind of drew a line over the top of the
petrous part of the of the temporal bone and you can see that there is a little bit of blue right
around this region here that's likely part of the superior petrus sinus which is located on
the superior portions of the petrous part of the temporal bone so this is a different type
of sinus the cavernous sinuses actually will end up draining into the petrous sinuses so there's
superior and inferior you can really only see the superior here because we'd have to remove
some of the some of the tentorium cerebelli and the superior petrus sinus will drain into
the proximal sigmoid sinus all right last image same superior view but note that the tentorium
cerebelli has been removed to get a better view of some of the deeper and the most distal sinuses
you can see a bit of the confluence of sinuses here and how it is going to flow into and I'm
tracing the transverse sinus here note that only the right transverse sinus has been opened that's
why it looks so blue here there's of course a left transverse sinus over here that's not quite
as visible just because we haven't opened up that sinus now once at the level of the petrous part of
the temporal bone there is a name change of this sinus into the sigmoid sinus so here is going to
be your sigmoid sinus so where it's making that sharp turn inferiorly not as visible in
this image you will have what's referred to as the inferior petrosal sinus so we saw the superior up
here on the superior portions the inferior will be on the inferior side of the petrous part of
the temporal bone it is this inferior petrosal sinus that will meet or drain into the sigmoid
sinus and once you get that confluence of those two you will have the formation of the internal
jugular vein at the jugular foramen lastly another difficult to identify dural venous
sinuses the occipital sinus you can see a bit of the falx cerebelli right here this
little thing right here which would have run in between the cerebellar hemispheres if the brain
was here that is where the occipital sinus will be located in that region so not particularly
easy to see in a dissection but that is where it would be it like the superior sagittal sinus
and the straight sinus will drain into the confluence of sinuses all right so that was
a lot of dural venous sinuses fine I am happy we got to spend some time working through how
to locate these and please do take time to review and try to identify these on your own as always
please feel free to reach out to me with any questions and thank you for your attention