hi let's talk about the arteries of the superior mediastinum and root of the neck
the story of any artery really begins with that of the aorta and the aorta
begins as a vessel that leaves the left ventricle and becomes the ascending aorta
that ascending aorta transitions into the arch of the aorta or aortic arch
and that arch has three major branches from it there's the brachiocephalic trunk
the left common carotid artery and the left subclavian artery the arch of the aorta then
transitions into the descending aorta which has both thoracic and abdominal parts
the other major artery leaving the heart comes from the right ventricle and that's
the pulmonary trunk the pulmonary trunk is going to divide into left and right pulmonary arteries
and we can see a remnant of a novelty of fetal circulation called the ligamentum
arteriosum at the origin of the right pulmonary artery now ligamentum arteriosum would conduct
relatively rich oxygenated blood coming from the placenta having traveled through fetal circulation
through the pulmonary trunk to the arch of the aorta so in effect it's a bypass of
pulmonary circulation for that blood as we take a closer look at
the branches coming from the arch of the aorta and you'll have to excuse this image because there's
still pericardium on these great vessels but we can see the brachiocephalic trunk the left common
carotid artery and the left subclavian artery that brachiocephalic trunk is going to branch
into the right subclavian artery and the right common carotid artery the subclavian arteries are
going to serve predominantly the upper limbs but they'll also serve the head and neck as well as
the walls of the thorax and abdomen whereas the common carotid arteries are going to bifurcate
into the internal and external carotid arteries the internal carotid artery predominantly supplies
the cranial cavity with blood the brain with blood and it does send a branch out through
the orbit the ophthalmic artery which supplies the orbit the eye various related features and
the superficial brow whereas the external carotid artery serves the neck face and head with blood
let's take a look at a subclavian artery in the root of the neck the subclavian artery
if you recall has three parts that are defined by their relationship to the anterior scalene muscle
the first part of the subclavian artery is everything medial to the edge of the
anterior scalene muscle the second part is anything behind that anterior scalene muscle
and the third part is anything lateral to the anterior scalene muscle
out to the lateral margin of the first rib where it then becomes the axillary artery
now that first part of the subclavian artery has three branches one of which is germaine to
today's or this session's lab and that is the internal thoracic artery that internal thoracic
artery is going to descend the thorax sending out branches of the pericardiacophrenic artery
anterior intercostal branches one through six and then its terminal branches will be the
musculophrenic artery and the superior epigastric artery thank you very much for your time