...anterior, middle and posterior.
Let's get rid of that.
If I bring in the brain, you can see how it just sits in this fossa.
I'll just get rid of the outer membrane and now you can see the cerebellum and the brain
stem sitting in the posterior cranial fossa.
You can see the temporal lobe sitting in the middle cranial fossa and you can see the frontal
lobe sitting in the anterior cranial fossa.
So now that I've covered that, we can go back to talking about
the foramen or foramina.
Just to remind you, I'm going to be doing this in few parts.
So if you're getting a bit bored by this and you want to see all the cranial nerves and
how they pass through, I'll be using views like this from the base of the skull, showing
you what kinds of structures pass through and views like this showing you how the cranial
nerves pass through.
But this tutorial, I'm just focusing on the foramina themselves.
So again, looking superiorly down at the base of the skull, I'm just going to work from
anterior to posterior and talk about these foramina.
So these holes here right at the front are the optic canals.
You saw them from the outside.
So these little holes here, which sit medially in the orbit.
That's the optic canal.
And then if you remember the superior orbital fissure, that's this here.
And just going back to the external view, the superior orbital fissure here, which you
can see.
So then we've got a few more which you couldn't see from the external view that I showed you
just before.
You've got these holes in the middle cranial fossa.
So posteriorly and laterally in the middle cranial fossa, you've got a little round hole
on either side here.
This is called the foramen spinosum.
That's the most lateral and posterior in the middle cranial fossa.
And then you've got this big oval-shaped structured -- well, not structure, hole.
It's just aptly named the foramen ovale.
And then -- you can't quite see it from here, so I'm going to rotate the skull around.
So you can see just below the superior orbital fissure, you can see this little round hole
here.
And again, this is named the foramen rotunda because of its shape.
That lies anterior to the foramen ovale.
So you've got the spinosum, the ovale, the rotundum and then you've got this huge laceration
here.
This is called the foramen lacerum.
In life, this is actually filled with cartilage.
So no structures actually pass through this one.
So again, laterally, you've got the foramen spinosum, then you've got the foramen ovale
and then you've got the foramen rotunda.
So that's the foramen of the middle cranial fossa.
Now we're just going to look at the foramen that you've got in the posterior cranial fossa.
This one here is the internal auditory meatus.
And then if you work yourself slightly inferiorly and posteriorly, you've got another foramen,
which is the jugular foramen.
Quite a few structures pass through that.
Working even further down, more inferiorly, you've got the hypoglossal canal.
And then obviously, you've got this huge one in the middle and that's the foramen magnum.
So again, 'magnum' in Latin means 'great', so it's the 'great foramen'.
The brain stem passes through here and this is where it becomes the spinal cord.
This is the foramen magnum.
So just looking at this view (because in a lot of atlases, you've got this superior view),
you've got the -- I can't quite see it.
You've got the internal auditory meatus, you've got the jugular foramen and then you've got
the hypoglossal canal and the big foramen magnum.
So just to very quickly recap what I've been over, you've got the optic canal at the front,
the superior orbital fissure, the foramen rotundum, you've got the foramen spinosum,
the foramen ovale, the foramen lacerum in the middle cranial fossa.
And then in the posterior cranial fossa, you've got the internal auditory meatus, the jugular
foramen and the hypoglossal canal, as well as the big foramen magnum down here.