Okay, so this tutorial is an introduction to the blood supply to the abdominal organs.
So I'm going to talk about the arterial supply and the venous drainage of the abdominal viscera.
So we're looking here at a model of the circulatory system and we're looking at the abdominal
region.
So here you can see the abdominal aorta and to the right of it, you can see the inferior
vena cava.
So first, let's just talk about the arterial supply to the abdominal viscera.
So I'll get rid of the veins.
So I got rid of the inferior vena cava and the veins.
We're looking at the abdominal aorta.
The abdominal aorta begins at the aortic hiatus of the diaphragm and it ends when it bifurcates
into the common ileac arteries.
The beginning of the abdominal aorta is roughly at the level of T12 and the end of the aorta
is roughly at the level of lumbar vertebra L4.
So you've got quite a few branches coming off the abdominal aorta, but it's the anterior
branches which supply the gut and the accessory organs in the abdomen.
So there are three branches which supply the abdominal organs.
Right at the top, you've got this branch here called the celiac axis or the celiac artery
or the celiac trunk.
You'll hear it called by different things.
And then you've got the superior mesenteric artery just below it.
And right at the bottom, you've got the inferior mesenteric artery.
So remembering what these branches supply is fairly straightforward.
The top branch supplies the foregut, that's the celiac axis.
The next branch down, the superior mesenteric artery supplies the midgut.
And the bottom artery, the inferior mesenteric artery supplies the hindgut structure.
So you might have noticed that there's a lot of branching from these articles and I'll
talk about these in a lot more detail in separate tutorials.
This is just an introductory to the blood supply to the guy.
So for the purposes of this tutorial, just remember that the top branch is the celiac
axis and you've got the superior mesenteric artery and the inferior mesenteric artery.
They supply the foregut, the midgut and the hindgut respectively.
So we'll just bring these structures in and show you what they are exactly.
The foregut runs from the abdominal esophagus down to the major duodenal papilla where the
bile duct empties into the descending part of the duodenum, so roughly mid-way down the
duodenum.
So the abdominal esophagus is the bit of esophagus distally just after it perforates the diaphragm.
So the foregut runs from this part of the esophagus.
It contains the stomach, the first part of the duodenum and it ends at the major duodenal
papilla.
So the foregut also includes the pancreas (which you can see lying behind the stomach
here) and it also includes the liver and the gallbladder as well as the spleen over here.
The spleen isn't part of the gut, but embryologically, it develops with these structures.
So the foregut runs from the abdominal esophagus down to the major duodenal papilla in the
descending part of the duodenum and it also includes the accessory organs of digestion
-- the liver, the gallbladder and the pancreas and it also includes the spleen.
So these structures are supplied by the celiac trunk or celiac artery.
So the celiac trunk lies in the transpyloric plane.
That's the level of L1.
It lies at the upper border of L1, almost T12 level.
So you can see this vertebra here, that's thoracic vertebra T12.
So just at the upper border of L1/T12.
So the celiac artery has three branches.
You've got the splenic artery, the left gastric artery and the common hepatic artery.
It's worth knowing these branches.
So next down, we've got the superior mesenteric artery, which supplies midgut structures.
You can see here, it lies at the lower border of L1, just below the celiac trunk.
The midgut runs from where we left off, so just at the level of the major duodenal papilla
and it covers all the small intestine and extends to two-thirds of the length of the
way across the transverse colon.
So the midgut extends from just below the major duodenal papilla.
It includes the jejunum and the ileum and it encompasses the cecum and the appendix.
It includes the ascending colon and then it includes two-thirds of the transverse colon.
So it ends about this point here.
So it covers the proximal two-thirds of the transverse colon.
That's the midgut and it's supplied by the superior mesenteric artery.
So then we've got the inferior mesenteric artery, which supplies the hindgut structures.
You can see it here, the inferior mesenteric artery.
You can see this is lumbar vertebra L3.
It lies at the inferior border of lumbar vertebra L3 and it supplies the hindgut structures.
So I just switched back to this view.
We're going to start off from two-thirds of the way along the transverse colon.
So the hindgut includes the distal third of the transverse colon, the descending colon
as you can see here, then you've got the sigmoid colon, the rectum and midway down the anal
canal.
So that's the hindgut supplied by the inferior mesenteric artery.