hi let's talk about the subclavian artery in this video i'll describe
to you how we distinguish the three parts of the subclavian artery from one another
the major branches from each part of the subclavian artery and what they supply
and then finally i'll show you where the subclavian artery turns into the axillary artery
so let's begin here by looking at this right root of the neck image this is an anterior view of the
right root of the neck the subclavian vein has been cut away there so normally this would have
continued on here but this allows us to see the the inferior attachment site for the anterior
scalene muscle the anterior scalene muscle is an excellent reference point for the root of the neck
especially with respect to the subclavian artery so here we can see the subclavian artery this is
a right subclavian artery so it originates from the brachiocephalic trunk and everything from this
bifurcation all the way up to the medial border of the anterior scalene muscle
is the first part of the subclavian artery
everything behind the anterior scalene muscle is the second part and everything lateral to the
anterior scalene muscle is the third part and that goes right up to the lateral edge of the first rib
after the lateral edge of the first rib it's no longer the subclavian artery it is the
axillary artery and that axillary artery will traverse the axilla and then beyond the inferior
border of teres major it will become the brachial artery so let's take a look at the branches of
the parts of the subclavian artery so again to remind you there's the beginning of the first part
and there is the boundary between the first and the second part and we have three branches there's
the vertebral branch which is a large branch heading superiorly there's the internal thoracic
which is a large branch heading inferiorly and then there's the thyrocervical trunk so let's
take these one at a time the vertebral artery branches from the first part of the subclavian
artery and then it heads superiorly and medially typically it's going to take a medial turn between
the 7th and the 6th cervical vertebrae and then it will enter the transverse foramina of c6 through
1 before then entering into the foramen magnum of the skull along the way it will send branches to
the spinal cord it will also serve some of the deep neck muscles along the way
and once it enters into the foramen magnum it will meet up with its counterpart the vertebral
artery from the other side to form the basilar artery so vertebral artery plus vertebral artery
equals basilar artery the basilar artery serves the brain stem and posterior aspects of the brain
and typically anastomosis with branches from the internal carotid which is coming from the
the anterior brain which we'll see the the next branch is the internal thoracic
artery the internal thoracic artery is going to weave itself down through the innermost
intercostal muscles alongside of the sternum as it descends the thorax it will send branches out to
serve the anterior body walls so the intercostal spaces those spaces between the ribs as well as
aspects of the mediastinum and then down to the the diaphragm and some portions
of the the anterior lateral abdominal wall as well which is neat and then we have this thyrocervical
trunk but let's address that on the next slide where we have a little bit of real estate
so let's think about this name thyrocervical firo thyroid cervical neck trunk so it is a trunk
that is going to serve various elements of the neck and you don't get this from its name uh
shoulder as well so let's let's take a look and see what we can see so here is that trunk and
there are four basic branches here there is the inferior thyroid artery that inferior thyroid
artery is going to ascend superiorly and medially to serve the thyroid gland which we can see here
it's also the dominant blood flow to the parathyroid glands and it will even
serve the larynx via an inferior laryngeal artery but we can't see that branching point
the next and most adjacent branching point is the ascending cervical artery the ascending cervical
artery is going to serve deep neck muscles such as the scalene muscles etc and then we have
the rather large transverse cervical artery the transverse cervical artery is heading over to
serve the trapezius muscle with blood sometimes this transverse
cervical artery about one out of every three cases it will supply the dorsal scapular
artery which is typically a third part of the subclavian branch we can see right
there and then finally from the thyroid cervical trunk going across and then back is going to be
the suprascapular artery suprascapular artery heads over the superior border of the scapula
by the suprascapular notch and it's going to supply two of the rotator cuff muscles with blood
these are the supraspinatus and infraspinatus which are located on the posterior aspect
of the scapula one is above the spine the other is below the spine and there are
also typical collateral connections between the suprascapular artery and other scapular arteries
um this image has that very important landmark the anterior scalene reflected
and we can see this beauty here this is the costocervical trunk costo
costal rib cervical neck and there are two branches to this there's the deep cervical
artery the deep cervical artery not pictured here serves the deep neck muscles and then there
is another branch that is winding down but not visible here called the highest intercostal
sometimes called the supreme intercostal artery that gives rise to um anterior first and second
intercostal arteries to serve the spaces between the first and second and second and third ribs
moving right along uh that anterior scalene has been laid down again and we have our third part
of the subclavian artery and its only branch which is the dorsal scapular artery
that dorsal scapular artery runs alongside the medial aspect of the scapula or the shoulder
blade and it's going to serve three muscles with blood the lever scapulae
which is an elevator of the scapula as well as rhomboid minor in major muscles
a third of the time this is going to be a branch of the transverse cervical artery but two-thirds
of the time it's from this third part of the subclavian then finally we can see there's our
rib one there's our lateral border of rib 1. beyond this boundary we have the axillary artery
that axillary artery supplies the axilla and shoulder with blood and it's an important
reference point for uh various divisions and uh chords of the brachial plexus so the the
anterior divisions are anterior to the axillary artery the posterior divisions of the brachial
plexus are posterior to it uh posterior cord is posterior to the axillary artery and medial
and lateral cords of the brachial plexus are medially and laterally respectively located
with respect to the axillary artery so that's uh that's an interesting naming convention which
leads us to our terminal assessment question for the video and that is which muscle can be found
sandwiched between the subclavian vein and subclavian artery is it the anterior scalene
artery oh i remember the anterior scalene artery is a very important
muscle with respect to the subclavian artery so we know that it's bordering the subclavian
artery we know that the first part is medial to the subclavian to the anterior scalene
muscle the second part of the subclavian artery is behind the anterior scalene muscle so that's
looking really good to us as as an answer if the anterior scalene muscle is behind the
i'm sorry if the subclavian artery is behind the anterior scalene muscle if we recall that anterior
scalene muscle attaches to the scalene tubercle of rib 1. so we have our lovely anterior scalene
muscle coming down attaching to that tubercle of the rib right there's our rib one going across
usually cut off behind that is our subclavian artery and in front of that is our subclavian vein
s-c-a-s-c-v so that's looking like a great answer middle scalene metal scalene is also
attaching to rib 1 but it is behind the subclavian array that's not a good answer
posterior scalene that's with the middle scalene behind the artery sternocleidomastoid now that's
way over here in the neck and trapezius no that's way back there on the back so anterior scalene
muscle final answer for the muscle that is betwixt the subclavian vein which is anterior to the
muscle and subclavian artery which is posterior to the muscle thank you very much for your time