Hi all This is Dr. Kingston and in
this video I'll be talking
about the pterygopalatine fossa.
The objectives for this session are
to identify the walls and boundaries of
the fossa and to describe
the major structures residing there.
To find the pterygopalatine fossa,
we first have to find the pterygomaxillary fissure.
But before we go ahead and find that it is a good idea to
orient yourself to the images in the slide
because they are not intuitive.
But they do a good job of showing what they need to,
once you've got a little bit more
of an idea of what's going on.
So on the left over here is
a lateral view of the skull and it
zoomed in on the infratemporal region.
So the bones making up
the walls of this area are colored and labeled.
So you've got maxilla in orange,
you've got zygomatic and temporal in purple,
and then you've got sphenoid in green.
And we have a very small little slip of palatine bone,
bone here in sky blue.
Coming over to the right.
Then what you're looking at over here is essentially
just the inside of the image on the left.
So it's the same bones.
You're just looking at it as if someone has
cut the skull directly down the middle of the orbit here.
So we're seeing the inside of the maxilla here,
where we were seeing the outside over here.
Same thing with the zygomatic and the sphenoid.
All right, so now that we've got ourselves oriented here,
Let's pop in the pterygomaxillary fissure.
And just like its name says,
this is a crack that is
located in-between the lateral pterygoid plate,
so the sphenoid, and the maxilla.
This is going to be our pathway
in to observe the pterygopalatine fossa.
So I find it helpful to think of
the pterygopalatine fossa is a cave.
The pterygo- maxillary fissure is
the big gaping entrance to the cave that we can
walk through and explore what's in there and
find some smaller passages inside.
The boundaries of the fossa are very
similar to those of the pterygomaxillary fissure.
So we've got the maxilla anteriorly
and the greater wing of the sphenoid here posteriorly.
But because the fossa is three-dimensional,
where that fissure is just two-dimensional,
it's also going to have a roof and a medial wall.
So the roof is made up by the body of the sphenoid.
And the medial wall,
which we can't see very well, would be in here.
It's going to be made up by the palatine bone.
Now, once you make your way into
this cave of the pterygopalatine fossa,
you spot a number of other openings.
The fossa has communications with
a number of other spaces in the head.
So we already know that it's open to
the infratemporal fossa through
that pterygomaxillary fissure laterally.
If we move medially,
we find the sphenopalatine foramen,
which will take us into the nasal cavity.
And now we're going to jump over
to the right side image for the others here
because they're easier to see from
a medial view. Posteriorly on the body of the sphenoid,
there are two passage ways.
So we have the foramen
rotundum is the more superior of the two,
and the pterygoid canal is the more inferior.
Hopefully foramen rotundum sounds familiar to you.
That is the passageway that is
going to take the maxillary nerve or
the maxillary division of
trigeminal out of the middle cranial fossa.
All right, anteriorly here we
find the inferior orbital fissure,
which will lead into the orbit
and eventually out onto the midface.
And inferiorly then we're going to
find the greater and lesser palatine canals,
which are going to lead into the oral cavity.
Now with all of these communications,
it has probably already
occurred to you that there must be a decent number
of things passing in and
out of the pterygopalatine fossa.
And you are definitely correct.
There's really only one full-time resident here.
And that is the pterygopalatine ganglion.
That is going to take up most of the room in the fossa.
So remember the pterygopalatine ganglion
is one of our parasympathetic ganglia,
and it's going to be housing postganglionic
parasympathetic cell bodies for neurons
that are going to head out to the lacrimal gland
and to the mucous glands in the nasal and oral cavities.
It is going to be receiving
preganglionic axons from the facial nerve
via the greater petrosal nerve.
The rest of the structures in
the pterygopalatine fossa are
kinda playing peekaboo as they
move in and out of the region.
These are going to be branches of
the maxillary nerve as it comes out
of foramen rotundum and branches
from the third part of the maxillary artery.
I am going to leave that description
intentionally broad for right now.
The maxillary nerve branches
and maxillary artery branches in
this region both have
enough material that they really
deserve their own learning objectives.
So we will be going through them in
great detail in sessions to come here.
Alright, so that is where I will
leave this learning objective.
And here is a practice question for you.
Correct answer here is B,
the nasal cavity and the sphenopalatine foramen.
So over here on the left,
that big hole right there is on
the medial wall of the pterygopalatine fossa.
And that is going to connect
this space into the nasal cavity.
And that brings us to the end.
Thank you for watching.