hello all and welcome to this discussion regarding the pertinent arteries and the anterior neck
session this is dr alsup we will have a focus on the blood supply of the anterior neck as the name
would suggest but we're also going to focus on the blood supply of the thyroid and parathyroid glands
so let's get started let's focus on the common carotid first and we and i'll point out on both
of these images where we can find the common carotid so you can see it located right here
as well as quite prominently on this kind of more anterior lateral image here
the common carotid is either a direct branch of the aortic arch on the left side which is
what we're seeing on both of these images or the brachiocephalic trunk on the right
we will see that a little bit more in subsequent sessions so those direct branchings this artery
is also the only one associated with the carotid sheath or at least the largest one
associated with the carotid sheath it is going to be the medial most large structure with the vagus
which is going to be more intermediate and deep and the internal jugular vein which will be the
lateral most structure associated with the carotid sheath so you can see in this particular image
here it is the medial most you can't really see the vagus nerve very well because it is deep
this is the ansa cervicalis which we'll talk about in terms of the strap muscles that usually sits
kind of either right within the carotid sheath or on top of the carotid sheath and then lastly here
is that internal jugular vein so you can see it's a fairly large prominent structure in this region
if you see an artery in the anterior neck region you are going to just assume that
this is the common carotid i think it's one of the easier arteries to locate
if you're looking over in this image you can see what we refer to as the carotid bifurcation
which is where it splits into the common carotid splits into its two terminal branches
this typically occurs at about the c3 or c4 level or just a little bit above the thyroid
the superior border of the thyroid cartilage which you can see here the head is tilted a
little bit higher in this particular donor so it looks a little bit higher than the superior
portion of the thyroid cartilage so let's talk about those branches of the common carotid
the terminal branches of the common carotid are the internal
carotid so this is going to be the internal carotid on this particular image this will be
over here so in this particular view we're looking at an anterior lateral view
this is a completely posterior view which we will see a bit more of this view in our
third session larynx and pharynx session we're looking at the pharynx right here
i want to start with the internal carotid because this one i think is easy to identify
because it is the branch of the common carotid carotid artery that does not have any branches
in the neck and you can see that pretty well here there's branches all over the place when we're
talking about the external carotid and absolutely none when we're talking about the internal carotid
it is typically the more lateral of the terminal branches but i don't want you to
focus on that so much focus more on the fact that there are no branches
the internal carotid will travel to the cranium it will enter via the carotid canal and supply
blood to the brain importantly as well as the orbit and the forehead so we'll spend a lot more
time on the internal carotid when we get to the cranial cavity and brain session
the external carotid and so this is the external carotid
on this image and it's pretty easy to id over here because of all the branches on the posterior view
the external carotid is the primary source of blood to the face and superficial head
and it has eight branches but we're just going to focus on one in this
particular session which is going to be your superior thyroid artery you can see that here
it will descend to the thyroid gland and the fact that it descends is important all other
branches of the external carotid will either move horizontally or it they will ascend so this is the
only branch that is descending so that's a nice way to be able to identify this one it has several
branches but the one that we want you to focus on and be able to identify is this one right here
which is referred to as the superior laryngeal artery you can see that over here as well
this artery accompanies the internal branch of the superior laryngeal nerve
which you can see right here so that's going to be a branch of the vagus nerve
this pair will pierce through the thyrohyoid membrane you can see that thyroid hyoid
membrane right here and you can see it kind of entering into that region and it's going
those that pair is going to serve and supply the superior larynx so you can see the
bulk of the superior thyroid will continue down to this region to get to the superior thyroid gland
the last artery that we want you to focus on in this session
is the supply to the inferior portions of the thyroid gland as well as the majority
of the parathyroid glands and this is going to be your inferior thyroid artery
so you can see just a little bit of it in both of these images this is not a branch
of the external carotid but rather a branch of the thyrocervical trunk which is a branch of the
first part of the subclavian artery so this is the subclavian artery here we'll talk about that
in more detail in some subsequent sessions and you can see this relatively short thyrocervical trunk
and it almost immediately will branch into three to four branches the one that ends up
traveling medially towards the inferior thyroid gland and here's your thyroid gland right here
this is going to be your inferior thyroid artery you can see the other
ones are either continuing to ascend for the ascending cervical or moving laterally
now i want you to notice and you can see it particularly well in this image
the close relationship with this nerve right here so you can see right about here-ish how closely
these two are related this is this nerve is the recurrent laryngeal nerve so this is an important
anatomical relationship this close relationship between the inferior thyroid artery and the
recurrent laryngeal nerve because if there's a need to ligate this artery say for some sort of
surgery involving the thyroid gland you have to be very mindful of this close relationship with
this nerve because it has serious implications in terms of the function of the larynx all right
so this has been a review of the arteries we want you to identify for the interior next session
as always please feel free to reach out to me with any questions and please have a great day