hi let's talk about the nerves of the superior mediastinum and root of the neck previously
we've discussed the carotid sheath and its major constituents namely the common carotid artery
the internal jugular vein and the vagus nerve or cranial nerve 10. we can see the vagus
nerve descending down it's leaving the jugular foramen and it remains within the carotid sheath
down through the root of the neck and it will continue on down towards the roots
of the lungs where it passes posterior to the roots of the lungs and it's going to contribute
branches along the way to many structures important structures in
the uh the soft palate as well as the neck and the thorax and ultimately we'll head into the
abdominal cavity to supply the foregut and the midgut with preganglionic parasympathetics
at the root of the neck on the right side the vagus nerve is going to send a major branch called
the recurrent laryngeal nerve that recurrent laryngeal nerve wraps around the right common
i'm sorry the right subclavian artery and heads towards the tracheoesophageal groove
where it is going to ascend along with the inferior laryngeal artery
to supply the larynx with innervation it will be motor innervation to all of the intrinsic
laryngeal muscles with the exception of the cricothyroid muscle it's going to return
somatic sensory information from the mucosa of the larynx inferior to the vocal folds and it
will also supply visceral motor or preganglionic parasympathetic fibers to the mucosa of the larynx
inferior to the vocal folds on the right side we can see the vagus nerve coming down here
it's going to send the right recurrent laryngeal nerve around the concavity of the aorta and it's
going to ascend in that tracheoesophageal groove there now both the right and the left recurrent
laryngeal nerves are going to send branches to the cardiac plexuses the left for the superficial
cardiac plexus and both the left and the right to the deep cardiac plexus which can be found
deep to the arch of the aorta and superficial or anterior to the trachea we can also see in
this image the phrenic nerves as they traverse the superior mediastinum on the way down to innervate
the diaphragm the phrenic nerves originate from the cervical plexus the cervical plexus
consists of contribution of ventral primary rami of cervical nerves one
through four and it also arises slightly from the brachial plexus the brachial
plexus consists of ventral primary rami of cervical nerves 5 through 8 and t1 now the
phrenic nerve roots are vprs of c3 and five and the mnemonic goes c345 keeps the diaphragm alive
because the phrenic nerve is going to innervate the diaphragm or the heavy diaphragm because
there are two of them here we can see the phrenic nerve descending down through the root of the neck
just anterior to that anterior scalene muscle here crossing over some of the branches from the
thyrocervical trunk namely the transverse cervical artery here and the suprascapular artery there
and we can see that that phrenic nerve then dives deep so it's going to be between
the anterior scalene muscle and what would be the subclavian vein over here as it descends down into
the thorax so we've discussed the two major nerves of the root of the neck and superior mediastinum
the phrenic nerve which is more lateral and the vagus nerve which we can see here
which is more medial and the vagus nerve additionally will have
recurrent laryngeal nerve branches in this region thank you very much for your time