hi let's talk about the major vascular pathways of the head neck and upper limbs
in this video we'll diagram the major vascular pathways both artery and vein of the head neck
and upper limbs let's begin with the aorta the aorta is the largest artery of the body
it's likely the most impressive vessel of all of the body its three parts are the ascending aorta
the arch of the aorta and the descending aorta the ascending aorta leaves the heart
conducting blood from the left ventricle and it feeds directly into the arch of the aorta
from there it descends and it has two parts the part within the thorax is known as the
thoracic part or thoracic aorta once it crosses the diaphragm it's known as the
abdominal part or the abdominal aorta but let's focus on the branches of the arch of the aorta
the first major branch is the brachiocephalic trunk let's think about that name brachio
of the arm cephalic of the head so they're going to be two major branches here the right subclavian
artery and the right common carotid artery subclavian arteries conduct blood largely to
the upper limbs but they also supply the walls of the thorax and abdomen as well as the brain
as well as elements of the neck so the subclavian arteries do a lot and we'll talk in granular
detail about them in a subsequent video the common carotid artery is going to ascend the neck within
the carotid sheath recall that that contains the common carotid artery the internal jugular vein
as well as the vagus nerve and it's going to bifurcate into internal and external carotids
which we'll see the next branch off of the break off of the arch of the aorta is the
left common carotid artery which mirrors the right common carotid artery and then the typically final
branch is the left subclavian artery so we'll have two subclavian arteries and two
common carotid arteries coming off ultimately from the arch of the aorta it's just that
the vessels on the right side come from that brachiocephalic trunk so the subclavian artery
on the right originates at the brachiocephalic trunk on the left comes from the arch of the aorta
it's tripartite so from its origin until its terminus which is at the lateral margin of
rib one there are three parts and these parts are designated by their relationship to this
muscle here which is the anterior scalene muscle everything medial to the anterior scalene is the
first part any branch that comes off behind the anterior scalene is from the second part
and anything that comes off of the artery lateral to the edge of the anterior scalene is
of the third part the subclavian artery when it crosses that plane of the lateral margin of rib 1
becomes the axillary artery that will be transmitted through the axilla the common carotid
arteries as i've said previously are ascending the neck within the carotid sheath and i'll
draw those margins of the sheath there those are condensations of deep cervical fascia and
the major constituents are the common carotid and its branches the internal jugular vein
the vagus nerve sometimes ances which is a motor branch of the cervical plexus
can either be embedded or within that sheath and superiorly we'll also have the glossopharyngeal
so cranial nerve 9 and the accessory cranial nerve 11 transmitted through
the superior portion of that sheath now the two terminal branches of the common carotid artery
are the internal carotid artery and the external carotid artery and these names are very helpful
the internal carotid artery keeps ascending it has no branches in the neck it enters the cranium
through the carotid canal of the temporal bone and then it goes superiorly to serve the brain as
part of the cerebral circle of willis it has some branches then that will exit the skull namely the
ophthalmic branch which is transmitted through the orbit which serves the orbit and portions of the
forehead with blood the external carotid artery is going to supply the portions of the neck uh
the face and the scalp as we'll see so here's a lovely illustration of the external carotid artery
we'll notice that it is anterior in position to the internal carotid artery its first major
branch is the superior thyroid artery which we've discussed already and there's a branch off of that
the superior laryngeal artery the next major branch is the lingual artery that's going into
the sublingual space to serve the tongue and other contents of the sublingual space
sometimes this artery shares a common trunk with the next artery which is the facial artery
the facial artery hops over the mandible and supplies the face with blood there are also
a few posterior branches here so the ascending pharyngeal artery the ascending pharyngeal artery
goes deep to serve the pharynx with blood there's an occipital artery which serves the occiput
with blood a posterior auricular artery auricular means ear so there's the external acoustic meatus
so one might imagine an earlobe there that artery runs posterior to that ear serving the oracle
of the ear as well as the skull posterior to that ear there's also a maxillary artery which we can't
see here but is a terminal branch of the external carotid the maxillary artery serves the deep face
so the infra-temporal fossa and it's ultimately going to even serve the the nasal cavity and
then the other terminal branch is the superficial temporal artery that superficial temporal artery
serves portions of the face as well as the majority of the scalp with blood we can see
here as a posterior view so the vertebral column has been cut away we can see the common carotid
artery there's the internal carotid artery heading up into the cranium you can see superior thyroid
lingual facial and then a couple of other branches that i'd rather not speculate on their
origin without seeing where they're targeting the veins are quite elegant in their overall layout
so when we think about the venous drainage of the head neck and upper limbs let's think about that
same pattern of arterial flow so the arteries have the subclavians and the common carotids well the
veins have subclavian veins that drain everything that the subclavian arteries provide with blood
so there are right and left subclavian veins and there are right and left internal jugular veins
we discuss these in the context of the carotid sheath so we can see that these ijv are descending
the neck they would be in that carotid sheath they're meeting up with those subclavian veins
to form the venous angle the venous angle is just that juncture of
of internal jugular vein with subclavian vein that marks the beginning of the brachiocephalic veins
so there is a left and a right brachiocephalic vein we can see the left brachiocephalic vein
there the left brachiocephalic vein is crossing over the midline and it is running anterior
to all of the branches of the arch of the aorta and sometimes
even the superior portion of the arch of the aorta itself so it's in very close proximity
that left brachiocephalic vein is longer and more oblique than the right brachiocephalic vein
and where these two veins come together we form the superior vena cava the superior vena cava
is draining all of the blood superior from the diaphragm
down into the right atrium of the heart so we've discussed all of the major vascular pathways of
the head neck and upper limbs many of these will go into much finer more granular detail as this
sequence and as the course progresses this is your summary slide thank you very much for your time