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Dr. P here.

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I want to talk to you about the descent of the vagus nerve.

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Now, here's the vagus and glossopharyngeal nerve.

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As we work our way down

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you can see the nerves crossing anterolateral,

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and you're going to follow them into a space right between

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the internal carotid artery and the jugular vein.

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Now, I'm going to go down as far as I can,

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and this is where you're going to find the vagus nerve on

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your way down, traveling between these two structures.

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So sometimes you're going to have to infer its location.

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And this is especially important when you're looking at

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glomus vagale tumors or schwannomas of the vagus nerve.

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Now, I'm going to go as low as I can.

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I've got the internal carotid artery.

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I can't see the external branches all that well,

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and I'm not down to the level of the common

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carotid artery yet, but that's relevant.

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So keep these two structures in mind.

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For the right and left vagus nerves descend from the

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cranial vault through the jugular foramen,

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and they penetrate the carotid sheath between the

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internal and external carotid arteries.

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And then they pass posterolateraly.

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We're not at the level

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of the common carotid artery, but if we were,

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if this were the common carotid artery,

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the perforation is kind of in a posterolateral orientation

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to the common carotid artery into the carotid sheath.

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Now, for those of you that are medical students

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or studying for anatomic exams,

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the cell bodies of the visceral afferent fibers

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of the vagus nerve are located bilaterally,

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bilaterally in the inferior ganglion of the vagus nerve,

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which is known as, board question, the nodose ganglion.

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Now, the right vagus nerve gives rise to the

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right recurrent laryngeal nerve,

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which I'm not going to show now because we're in the brain,

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and it hooks around the right subclavian artery and

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ascends into the neck between the trachea and the

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esophagus, in the right tracheoesophageal groove.

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The right vagus then crosses anterior

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to the right subclavian artery.

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It runs behind the superior vena cava and descends

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posterior to the right mainstem bronchus and then

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contributes to cardiac, pulmonary, and esophageal plexuses.

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It forms the posterior vagal trunk as

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the lower part of the esophagus,

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and then it enters the diaphragm

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through the esophageal hiatus.

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Now, you can stop right now if you want,

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but for you med students and residents out there,

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the left vagus nerve then enters the thorax on the

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opposite side between the left common carotid

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artery and the left subclavian artery,

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and it descends on the aortic arch.

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It gives rise to the left recurrent laryngeal nerve,

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which hooks around the aortic arch to the left of the

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ligamentum arteriosum and ascends between the

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trachea and esophagus in the left TE groove.

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The left vagus further gives off thoracic cardiac

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branches. It breaks into a pulmonary plexus,

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it continues into the esophageal plexus,

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and finally, it enters the abdomen as the anterior

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vagal trunk in the esophageal hiatus of the diaphragm.

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Probably more than you wanted to know,

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but Dr. P out.