hello all this is dr alsup and in this dissection video we are going to talk through how to identify
the vasculature associated with both the abdominal wall and those associated with the intestine
and so let's start with the abdominal wall first which is all about the epigastric vasculature
we actually saw one of these in the thoracic wall dissection the superior epigastric which i am
kind of outlining that vasculature right there the superior epigastric artery is one of the terminal
branches of the internal thoracic artery and it's the one that descends into the abdomen and you can
see a bit of it here but the dominant supply for the abdominal wall as you can see here by the size
is the inferior epigastric artery and then of course the vein is going to drain the similar area
the inferior epigastric artery is a branch of the external iliac artery
and these arteries will anastomos or communicate deep to the rectus abdominis which you can see
here has been reflected inferiorly you'll also be able to see this vasculature
when the abdominal wall has been reflected so if you think about reflecting the anterior
abdominal wall inferiorly and looking at the deep surface you can still see the inferior epigastric
vasculature either through the lateral umbilical fold or if the peritoneum is
removed like in this particular image you can see it quite well and always remember that the
inferior epigastric vasculature is going to be located medial to the deep inguinal ring
all right moving to the deeper viscera and recall that the superior mesenteric artery or the SMA
which you will often hear us refer to it as is going to be the main blood supply to structures
derived from the mid gut so this includes the majority of the small intestine and a good amount
of the large intestine two the SMA is large and it's relatively long as well um particularly in
comparison to the celiac trunk which we'll talk about more detail in other sessions and
that celiac trunk is going to supply the foregut branches that come off of the SMA towards the left
are going to be branches that are destined for the small intestine whereas branches coming off
on the right are going to be more heading towards the large intestine and we'll talk about those
in more detail in a moment so you can see the multiple branches um or the multiple jejunal and
ileal branches of the sma heading this way and as you will see in the next image these branches will
produce these very complex arterial arcades within the mesentery of the small intestine
the SMV which i'm outlining right now is typically located just to the right of the
superior mesenteric artery and is typically fairly large in caliber kind of similar to
the artery and we'll see this vein again as we talk through a bit more
of the the structures if we remove some of the viscera it's a little bit easier to see
and real quick before i move on here are some of those arterial arcades that we
were talking about that forms within the mesentery and that goes to supply
the small intestine so it's really complex in this region the veins will do a similar thing
okay so in this image some of the small intestine has been removed to focus a bit more on the
blood supply on the right side of the large intestine here is the sma again here is the smv
and note that the transverse colon has been reflected superiorly almost to where you can't see
it you can see a little bit of it right there so the transverse colon has been reflected superiorly
typically the most inferior branch of on the right for the sma is going to be the iliocolic
artery right here and it also tends to be one of the largest branches of the sma
the iliocolic will supply predominantly the cecum but it will also send branches to the ileum
and also will give off a branch to the appendix which you can see right here
so that would be the appendicular artery right here now before i move on to the next branch
let's talk a little bit about the marginal artery which i'm going to kind of trace
here and it will extend all the way over towards the left side of the body as well
the marginal artery can be seen throughout the inferior border of the large intestine and all
of these branches of the sma and of the ima on the other side that will send branches to the marginal
artery that will directly supply the large intestine so you'll see it kind of throughout
the the whole span or almost the whole span of the large intestine occasionally there'll
be kind of breaks in the marginal artery but oftentimes it'll pick back up again
okay moving on you have the right colic artery uh which will supply the ascending
colon in this case it's coming off of a common trunk with the iliocolic
you can see extending to the marginal artery and lastly on this image you can see the middle colic
artery which is a bit out of place because recall the transverse colon has been reflected superiorly
okay in this view we are looking a bit more inferiorly than we were in the previous
image here is the sma and as we move inferiorly on the descending aorta or the abdominal aorta
you can see what i'm outlining right here the ima or inferior mesenteric artery
now um you can see coming off of the ima three major types of branches
you will have the left colic which will supply the descending colon through the marginal artery
you can see a bit of the marginal artery right here the sigmoid arteries which i'm outlining
right here are going to as its name would suggest supply the sigmoid colon these
branches will descend inferior laterally and typically there are more than one sigmoid artery
as is the case here and the branch that descends a little bit more towards the midline is going to be
the superior rectal artery and it often looks like a continuation of the inferior mesenteric artery
and right here you'll see a bit of the inferior mesenteric vein and
we'll talk about this in a bit more detail in the next image
all right this last image is a good review image i would take some time on your own to kind of see
what you can label and then you can kind of refer back to the blue link images to
see how you did but there's a few things i really want to hone in on on this image
first i want you to note again the marginal artery and how it kind of extends throughout the whole
inferior border or the majority of the inferior border of the large intestine the transverse colon
again has been reflected superiorly so there is a bit longer of a span there than would be typical
but what i really want to draw your attention to here is to review the sma and ima and
look at the same named veins so the sma again so your sma right here is going to be superior to the
inferior mesenteric artery which is located right here the sma has a prolific amount of branches
all right compared to the inferior mesenteric artery there's going to be
branches all over the place in terms of the sma and the smv or the superior mesenteric
vein is very closely associated with the sma so it's just right just to the right of the artery
the inferior mesenteric artery is smaller in caliber so it's going to be smaller it's
going to have less branches and i always like to think of the inferior mesenteric vein or your imv
as kind of doing its own thing it is quite it's comparatively quite a bit more lateral to the ima
than say what you have in comparison to the sma and the smv so the eye the inferior mesenteric
vein is a bit more lateral to the inferior mesenteric artery the imv's most typical pattern
has it draining into the splenic vein which is going to be kind of deep to these structures right
here the splenic vein and the superior mesenteric vein will join to form the hepatic portal vein
excellent that was a lot of vasculature fun thank you for your time and attention here and please
reach out if you have any clarification questions have a great rest of your day