Vagus Nerve Anatomy
HIDEInteractive Transcript
0:01
This is a diagram of the course of the vagus nerve
0:04
and its branch, the recurrent laryngeal nerve.
0:07
As you can see,
0:08
the vagus nerve courses posteriorly
0:11
in the carotid sheath.
0:13
Now, you will also see that the
0:15
sympathetic nervous system plexus
0:17
courses posteriorly in the carotid sheath.
0:19
The difference is that the vagus nerve is kind of in
0:22
between the carotid artery and the jugular vein,
0:26
whereas the sympathetic nervous system
0:28
plexus is behind both of them.
0:30
So the vagus nerve pathology in schwannomas tends to
0:33
displace the carotid artery anterior medially,
0:37
but the jugular vein posterior laterally,
0:40
as opposed to sympathetic nervous system plexus lesions,
0:43
which push both anteriorly.
0:46
This diagram also shows that,
0:48
at least for those of us looking in the neck,
0:50
one of the primary roles of the vagus nerve
0:54
is the innervation of the larynx.
0:56
The predominant innervation of the larynx is through
0:59
the recurrent laryngeal nerve. By recurrent,
1:01
we mean that the vagus nerve comes down and then the
1:05
recurrent laryngeal nerve comes back up and it courses
1:09
underneath the aortic arch on the left side and
1:13
the subclavian artery on the right side.
1:17
This is demonstrating the right side, for example.
1:19
And then this nerve comes back up and innervates
1:22
the muscles of the larynx.
1:24
So this involvement of the recurrent laryngeal nerve
1:28
is the most common source of vocal cord paralysis.
1:32
It is true that there are superior laryngeal nerves
1:35
which come from the vagus which have
1:37
a minor role in innervating the larynx.
1:40
Suffice it to say that schwannomas of the vagus nerve
1:45
are going to be between the carotid artery and the jugular
1:49
vein, displacing the carotid artery, as I said,
1:52
anterior medially, and the jugular vein posterior laterally.
David M Yousem, MD, MBA
Professor of Radiology, Vice Chairman and Associate Dean
Johns Hopkins University
© 2024 MRI Online. All Rights Reserved.