all right hello anatomy friends let us talk about some arteries a lot of our videos have
focused a lot on the joints and the muscles so it is important to talk about what's actually
supplying blood to these structures so we will focus first on the axillary artery and how we
divide up the axillary artery what are the main branches and then we'll finish talking about the
important area and a stenosis that that are going to be some of the branches from axillary artery
and the subclavian okay so as you hopefully recall from some of the active learning sessions there is
going to be one main artery that really supplies the upper limb and it basically just changes its
name in certain areas so we're looking here at the root of the neck we know this because here's your
thyroid gland you can see the common carotid coming off the thyroid cervical trunk here and
then this right here is the subclavian artery so we would remember dissecting this when we
were dissecting the root of the neck you can see a little bit of the lung here this is your anterior
scalene muscle if you recall that remember that is the muscle that kind of subdivides
the subclavian artery and the axillary artery is going to begin right about here --is-- and
the reason I know this is because I can see your first rib here so this is the first rib it's been
cut I also know this is the first rib because the anterior scalene attaches on the first rib
so just distal to the first rib is where the name change occurs and now we are calling this vessel
or this artery the axillary artery and so we're now out of the root of the neck and we're moving
more into the axial axillary region as its name would suggest now before we move on there are go
to be two arteries that are going to come off of the subclavian that are going to play a role in
terms of the posterior scapular anastomosis that we'll see later but I just want to have a
nice review we've looked at these previously well back in the first or excuse me the second block
but let's review real quickly while we're here all right so this is the subclavian artery this
is the first part of the subclavian artery and this is your thyroid cervical trunk off of the
thyroid cervical trunk which is right here it's at first part of the subclavian you're going to have
an artery called the Supra scapular so you have a lot coming off the thyroid cervical trunk you'll
also have the transversus cervical here which is usually superior to the super scapular but I
do want to point that one of those branches of the thyroid cervical trunk is the suprascapular artery
and it is heading back towards the posterior part of the scapula and you can kind of see it heading
in that direction so that's going to be one of the branches that's going to anastomose on the back of
the scapula the other one is right here and this is your dorsal scapular it is typically in the
third part of the subclavian and that makes sense if this is the anterior scalene lateral to the
anterior scalene there's only one branch wishes the dorsal scapular and you can see that pretty
clearly here the thyroid cervical trunk is on the first part or medial to the anterior scalene and
so super scapular and dorsal scapular we'll see again when we're looking at the posterior scapula
but wanted to show you here where it's actually coming off of the subclavian artery okay so let's
move down into the axillary artery and axillary vein now in this particular image you do not see
the axillary vein you can see kind of where the where it has been cut in this region but it would
be anterior to the axillary artery but we wanted to focus the the artery and the artery branches
because typically they're a little bit easier to see and the veins just kind of follow along
with the arteries as well so similar to what we had with the subclavian artery this artery
will be subdivided into parts as well and this is going to be subdivided by the pectoralis major so
the pectoralis major remember is going to kind of be located in about this ish region so the
muscle belly would be right here you can see a little bit of the tendon right here and it will
subdivide from there maybe went a little to a kind of distal right here but this is where the belly
would be so this would make this the first part of the axillary artery this would be the second
part and so the second part would be deep to the muscle belly of pectoralis major or excuse
me minor and then the third part is going to be lateral to the pectoralis minor the first part is
going to be medial second part is deep third part is lateral or distal similar to what we had with
the subclavian with the anterior scalene now if we're talking branches the cool thing about the
number of branches that's going to correspond with the part number so the first part will only have
one branch and this is going to be the superior thoracic we're not having you identify this one
but we do want you to conceptually understand that this is coming off of the first part you
can see it kind of heading towards the intercostal regions the second part has two branches but we're
only having you identify one which is the thorah chromium and you can see that right about here
ish and that it's a fairly short trunk before it starts to send off numerous branches to different
areas some of the more important areas are pectoralis major and minor as well as the
deltoid they'll be branches to that as well so it's a fair short trunk and then almost immediate
branches the second branch of the second part of the axillary is the lateral thoracic and you can
actually see that here we're not having you ID'd that but I am going to point it out since you can
see it on this image and that's heading to supply the serratus anterior okay so first part has one
branch second part has two branches third part so distal to or lateral to the pectoralis minor is
going to have three part or three branches so the first and typically the largest and this one's a
little on the smaller side but this is your sub scapular and the subscapular is another example
of a fairly short trunk before it splits into its two terminal branches and those are Thoracodorsal
which you can see here and the reason I know this is Thoracodorsal is because it looks like
it's going to supply your latissimus dorsi all right so it's the one that's going to continue
inferiorly to head towards the muscle belly region of the latissimus dorsi how I can differentiate
it from the other terminal branch of subscapular which is the circumflex scapular is that Thor echo
dorsal should be heading inferiorly circumflex scapular is going to kind of move backwards to
head towards the scapula so one's heading down one's heading laterally to get to the scapula
so that's how you're going to tell the difference between those two terminal branches the other two
branches of the third part of the axillary are the anterior circumflex and you can see this
heading anteriorly and the posterior circumflex which is typically considerably larger in terms
of diameter than the anterior circumflex and you can see that is the case on this particular donor
here so anterior circumflex posterior circumflex these are heading to kind of loop around the
surgical neck region and that's an important point here the surgical neck of the humerus
remember that one that is not the anatomical neck which is right next to the head this is
that kind of thin portion of the shaft just distal to the greater and the lesser tubercles so the anterior circumflex in the posterior circumflex well circumflex or circumvent or go
around basically the surgical neck region now looking back at this again hopefully this is a
familiar image to you you can see the posterior circumflex here as well as the axillary nerve so
remember the axillary nerve is one of the terminal branches of the brachial plexus it's going to go
supply the deltoid which you can see is reflected here and these two kind of travel together on the
posterior side of the surgical neck of the humerus so that relationship between those two if you have
a fracture to the surgical neck of the humerus not only can you not only could that affect the
posterior circumflex from the world but it could also affect the axillary nerve which is going
to be with supplying or innervating the deltoid muscle as well as teres minor so this is heading
in this posterior region here so you could also see posterior circumplex here okay so to that
promised anastomosis that I talked about on the posterior scapula now we know we're looking at a
posterior view and I might sound like a broken record because I've said this in quite a few
videos that I've recorded by now I'm looking at a posterior view because here is that scapular
spine and if you continue laterally then it will transition into the acromion there are
going to be three main branches that are going to play a role in terms of the scapular anastomosis
and specifically these three branches will send smaller branches that will actually Ness the most
with one another so let's figure out which one is which for me when I am trying to identify or
differentiate between these I always trying to find the dorsal scapular first I feel like it's
one of the easier ones to locate and it is always very much kind of following along the border the
medial border of the scapula and so you remember that medial border is going to be right along here
because acromian's always lateral so this is the medial border and this fairly large artery
the dorsal scapular is going to just follow along this medial border here so this is dorsal scapular
here now review we just discussed this but these are the kind of things that I hope that you're
remembering what is the dorsal scapular artery or branch of it is a branch of the third part
of the subclavian alright so with this is coming all the way from the subclavian additionally the
suprascapular is also coming from the subclavian or that first part of the subclavian and it is
going to be located on the superior portions of the scapula and sending branches to this posterior
portion here so subclavian this is subclavian branch this is subclavian branch and then you're
going to have an axillary artery branch which is your circumflex scapular as we just saw on
that anterior view coming off of the subscapular subscapular artery excuse me so what this is going
to do is going to kind of wrap around this more lateral border of the scapula so you can see kind
of the the larger diameter the bulk of the artery and then it's sending these small branches to the
posterior portion so you have an area here where you can have an estimate ease between branches
of both the subclavian and the axillary so if you have say some type of occlusion that occurs
right around the beginning of the axillary artery even in the second part of the axillary artery the
posterior scapula can still have blood supply because you are having some subclavian artery
branches associated with it so this is one of my favorite pictures it's a this is a particularly
difficult dissection but you can really clearly see the basic locations of these three main
branches of the posterior scapular anastomosis so to review dorsal scapular along the medial border
super scapular is going to be associated with the superior portion of the scapula it's going to go
through what's called the suprascapular notch kind of above it and then send off branches here and
then your circumflex scapular which is a branch of the axillary is going to kind of loop around this
lateral border of the scapula to send branches to anastomose alright so that is a kind of a review
of the arteries in the axillary region as well as the posterior scapular anastomosis hopefully this
is a nice review from the overview session and the the shoulder and brachial plexus session as always
we love talking arteries when us anonymous and so please feel free to to reach out and hopefully we
can help with some tricks of the trade in terms of identifying some of these branches but as
always understanding what these branches are going to supply will help you understand why
a certain artery needs to be heading in certain directions alright have a good rest of your day