This tutorial is on the foramina of the skull.
So foramina are openings which allows structures to pass through in the body.
So if you just look at this model, you can just see these little holes here, which if
you've watched the other tutorials I've done in the skull, you'll have seen and probably
wondered what they were.
These are called foramen and the plural is 'foramina'.
And again, these are all Latin, coming from the Latin names that they have.
So a foramen allows a structure to pass through, so things like blood vessels and nerves.
In the skull, they're really important to know because many important blood vessels
pass through these foramina to supply the brain and several important nerves pass through
them to carry information to and from the brain.
It's quite a complicated topic, so I'm going to break it into a few parts just to make
things a bit more digestible.
So this part, I'll start from an external view, looking at the skull and the various
foramina.
I'll go to an interior view and take a look at them from there.
And then there are other parts of this tutorial which we'll follow on.
I'll talk about all the different structures that pass through.
It's really important that you know about these because med schools in particular love
to ask questions about which structures pass through which foramen.
So to begin with, I'm going to talk about the foramina that you can see from the outside
view of the skull.
So starting superiorly, looking into the orbits of the skull, we can see quite a few little
holes, which are quite important to know.
Most medially, you've got this little hole here and this is called the optic canal.
When I talk about these, you've got them on both sides.
So they're bilateral.
You've got the optic canal here, which is most medial.
You've got this big opening here, which isn't technically a foramina.
It's referred to as a fissure.
As you can see, it's a big sort of opening in the skull.
So this is the superior orbital fissure.
If you look just inferior, you can probably guess, you've got the inferior orbital fissure.
So in the orbit, you've got this optic canal, you've got this superior orbital fissure and
you've got the inferior orbital fissure.
These are bilateral, so they're on both sides.
Just to demonstrate what structures pass through, I'll just show you some nerve and some blood
vessels.
And again, I'll be talking about these in detail in the next few parts because there's
quite a lot to get through.
So as you can see there's this big nerve here coming through the optic canal.
You've got blood vessels and you've got all these little nerves coming through this fissure.
And again, if we just zoom out a bit, you can see these vessels just emerging.
So that's the foramen, which you can see in the orbit.
We'll just get rid of that.
So just moving on to these ones here just inferiorly, you've got these little foramen
which lie in the maxilla.
So this is called the infraorbital foramen because it's below, infra-, below the orbit.
You've got these on both sides.
These, you get the infraorbital nerves and vessels which pass through this.
The supraorbital foramen, which is just a little notch here is also referred to as the
supraorbital notch.
So again, supra-, above the orbit.
And this allows the supraorbital nerves and vessels to pass.
So if you just move a little bit laterally, we've got this little hole here.
This is the zygomatico facial foramen.
And again, you've got this on both sides.
This allows the zygomatico facial nerve to pass through.
Try not to worry about what passes through in this tutorial.
Just try and remember the names.
I'm trying to remember them in terms of their position because all terms in anatomy are
relatively logically named.
It makes it a little bit easier to try and remember if you remember why they're named
that.
So infraorbit, below the orbit, infraorbital foramen.
And then right down here, you've got these little holes, these foramina.
These are the mental foramen and they allow the mental nerves and vessels to pass.
So those are the foramina you can see externally.
So next one I'm going to do is I'm going to switch to a view inside the skull.
So if you just see what I'm doing, I'm just going to get rid of the outside of the skull
and we're going to take a look from inside.
I'm just going to bring it around and we can have a good look.
So we're now looking at the base of the skull from the inside.
I got rid of the outside of the skull and we're looking down at this base of the skull
at the foramen from that perspective.
So if I just go back to that.
So anterior is up here and this is posterior just so you can orientate yourselves.
So just before I start talking about the foramina of the skull, I'm just going to talk about
the cranial fossa because you'll often hear people referring to these.
So again, anatomy is like another language.
It's a lot of words you'll hear repeatedly because they actually mean something in Latin.
It's useful to try and remember what these words mean.
So a 'fossa' is just a ditch in Latin.
It's like a little hallowing.
So if you look from a lateral view, you can see that there are three little ditches here
in the brain, fossa.
You've got the anterior one, which is the anterior cranial fossa, the middle cranial
fossa and the posterior cranial fossa, which is most inferior also -- so three cranial
fossa.
It's useful to know about these because people will describe structures which pass through
various cranial fossae (which is plural).
From a superior view, which I'm now showing you again looking down at the skull, you've
got the anterior cranial fossa which is this part.
This anterior cranial fossa forms the roof of the nasal cavity and the central part.
So this central part of the anterior cranial fossa forms the roof of the nasal cavity.
You've got the cribriform plate and the crista galli, which you might remember from my other
tutorials.
And then laterally, these lateral portions house the frontal lobes of the brain.
So that's the anterior cranial fossa.
And then you've got the middle cranial fossa.
It's all this bit, which I'm showing you with the mouse.
So all around here, this is the middle cranial fossa.
Posteriorly, you've got the dorsum sellae, this structure here.
That's the back of the middle cranial fossa, this dorsum sellae, which you might remember
from another tutorial.
And then you've got the posterior cranial fossa right at the back, which contains the
brain stem and cerebellum.
It's the most inferior fossa.
So just again looking laterally...