If we were to do a
section through the abdomen,
then we will see these peritoneal cavities: the
greater and lesser sac and the various compartments
in more detail. Now what is this rather complicated
diagram on the screen. Well this is a
section, a sagittal section, through the abdomen
and here we have got the vertebral column.
So this is posterior, we have got the
vertebral column, we have got the aorta.
This is the diaphragm here
and the liver, the stomach
the transverse colon. This is just
the part of small intestines
and here we have
got the pancreas.
Here we can see the bladder and we have got the
rectum and this is going to be the anterior abdominal wall.
Now the peritoneum lines the
anterior abdominal wall.
It lines the anterior abdominal wall
so here we can see we have got
parietal peritoneum just in
green here, parietal peritoneum.
Now if we were to follow that, if we
were to follow all the way up
with the run over
underside of the diaphragm
we'll then importantly see actually
run down to attach to the liver.
And this is an important transition
between parietal peritoneum
and visceral peritoneum. With the visceral
peritoneum now running over the liver.
We can see this piece of
green is completely continuous
and we have parietal peritoneum and
we now have visceral peritoneum.
The same continuous sheet but the
visceral peritoneum is over the organ
over the body wall.
We can then follow that and see
that it extends away from the liver
to the stomach. So we can see we now
have a layer that is going from the liver
to the stomach. We can then follow it
all the way around the stomach.
And then dangling down from the
stomach we find we have this
membrane this apron like membrane that
is running down from the stomach.
Once it gets inferiorily
it then runs back up
and it goes over the transverse colon
towards the posterior abdominal wall
in line with the pancreas
and then it returns towards the
transverse colon, surrounds it
and then runs back to the pancreas.
So what we have described
is the lesser omentum here.
We have described the lesser omentum here.
We have described the greater omentum here.
Lesser omentum, the greater omentum. Remember
these peritoneal structures that are suspending the liver.
We can then see that running
back towards the pancreas.
And then running towards the transverse colon
we have found the transverse mesocolon
suspending the transverse colon.
We can then follow this parietal
peritoneum down in this direction
and we see how we
have these two layers
along the posterior abdominal wall and
they are radiating over the small intestine.
So we have parietal
peritoneum and we have
visceral peritoneum. And
what we have got here
is the mesentery.
We can now see how these mesenteries allow
these organs to move around within the abdomen.
Now everything in
this space here,
this free space is known
as the greater sac...
is known as the greater sac.
If we now look at the peritoneum
that's forming this lesser sac
we can now look at in blue. The same principles
have applied. But this time we now
posterior to the stomach. We can see we have a running
parietal peritoneum here over the diaphragm
it's then connecting to the liver and
then it's running over the liver here
as visceral peritoneum. It then
runs towards the stomach
where we have now got
the lesser omentum again
running over the stomach, the underside of the
stomach here, so run on the inside of the greater omentum.
And then it's running up back towards
the posterior abdominal wall.
And all of this in here is the
lesser sac or the omental bursa.
The lesser sac or the omental bursa. And if
you remember from the previous slide
these two sacs can communicate.
This is the lesser omentum
This is the lesser omentum
which we can see here.
Lesser omentum between the
liver and the stomach.
And in this slide we can see the lesser
omentum, and the liver and the stomach.
And we can communicate the greater
sac here. The greater sac
that communicate with the lesser sac via
the epiploic foramen or the omental foramen.
And that's just going to be a little
aperture here that allows it to communicate
in the greater sac to the lesser sac.
Greater sac towards the lesser sac.
We can also pick up some other
important peritoneal ligaments.
Remember a peritoneal ligament is a double layer.
We have got a layer here and a layer here.
And this important is
our coronary ligament.
And we will look at that in more detail
when we will come to the liver.
So we can see have got
a whole series of
greater omentum, lesser omentum.
We have got the greater sac.
We have got the lesser sac.
And we can see, we will be able to
develop the idea of peritoneal ligaments.
The final part I want to do just on this
section is, looking at the greater sac again
and this supracolic and infracolic compartment.
This is relatively straight forward.
All you have to do
is just lift out the
transverse mesocolon and the greater omentum
and form this great kind of separation
in this kind of direction. Everything
down here is infracolic compartment.
And everything above is
the supracolic compartment.
So we can see in the infracolic
compartment we have got the colon.
We have got the small intestines and in the
supracolic compartment we have got the stomach.
We have got the liver, for example.
Just different regions of the abdomen
within this greater sac.