hi let's talk about the branches off of the arch of the aorta the arch of the aorta is supplied
by the ascending aorta so the ascending aorta moves into the arch of the aorta
and then it is continuous with the descending aorta so let's focus on the branches from the
arch the first major branch is the brachiocephalic artery brachio arm cephalic head and there are two
branches to the brachiocephalic artery there is the right subclavian artery that right subclavian
artery is heading out through the root of the neck and will transform itself into the axillary artery
and then into the brachial artery and we'll discuss that later and then there is the right
common carotid artery that right common carotid artery is going to ascend the neck within the
carotid sheath the carotid sheath is going to have major contents of that common carotid artery
internal jugular vein and vagus nerve as well as contributions from the glossopharyngeal nerve and
the accessory nerve at the top of the sheath and in some cases we might also see ansys cervicalis
embedded within that sheath but needless to say that common carotid artery is heading up
towards the superior portion of the neck where it's going to bifurcate into the internal and
external carotid arteries to be discussed the next major branch off of the aortic
arch is the left common carotid artery which will have typically all of the same branches as
the right common carotid artery and then finally the left subclavian artery which is going to have
all of the same branches as the right subclavian artery so as you notice there are right and left
subclavian arteries and right and left common carotid arteries the only difference
in terms of the arch of the aorta is that on the right side there is this brachiocephalic trunk
now let's take a look at that common carotid artery so here we have the contents of the carotid
sheath all dissected out there is the internal jugular vein there is cranial nerve 10 the the
vagus nerve and some of its branches descending down within the sheath and here is the common
carotid artery and we can see that common carotid artery bifurcating into an external carotid artery
and an internal carotid artery and that
internal carotid artery is more posteriorly oriented in the external carotid artery is more
anteriorly oriented and so that external carotid artery is going to supply elements of
the neck with blood elements of the face with blood elements of the sublingual space elements
of the infratemporal fossa with blood elements of the skull with blood whereas the internal carotid
artery has no branches in the neck it ascends up but before it does so at its origin
there's a dilation known as the carotid sinus so let's let's pay attention to the
the image here this is a posterior view of the bifurcation of the common carotid artery there
is the external carotid there is the internal carotid and we can see that dilation of the
internal carotid there known as the carotid sinus and within the walls of the carotid sinus we have
specialized stretch receptors or baroreceptors that give feedback to the central nervous system
with respect to blood pressure up to the brain and there's also an association with this region
known as the carotid body which is a chemo sensor for the blood that's traveling up into
the internal carotid most of the uh the donors at this age uh lack a carotid body it is atrophied at
this point and so this this isn't something that we'll be able to see on this particular specimen
but the internal carotid artery ascends it enters into the skull through the carotid canal which is
an osseous pathway through the temporal bone and it's going to give rise to branches within
the cranial cavity things like the middle cerebral artery the anterior cerebral artery
the posterior communicating branch which can meet branches of the vertebral artery coming from the
subclavian to form the cerebral arterial circle of willis and it also produces the
ophthalmic artery which runs through the orbit and even exits branches from the orbit to serve the
uh the superior portion of the uh the face with blood as well thank you very much for your time