The vagus nerve is the 10th Cranial nerve. It is the largest nerve of the parasympathetic nervous system and is involved in regulating the activity of almost all internal organs. The vagus nerve emerges lateral to the olive and courses laterally and caudally toward the posterior portion of the Jugular foramen, through which the vagus nerve exits the bony skull.
Anatomy
Course in the neck
In the neck, the vagus nerve courses together with the Common carotid artery and the internal jugular vein within a common connective tissue sheath, the carotid sheath, toward the thorax. At the superior thoracic aperture, the right vagus nerve courses over the right subclavian artery, while the left vagus nerve courses over the aortic arch.
Course in the thorax
In the thoracic cavity, the vagus nerve traverses the superior mediastinum and later the posterior mediastinum. There, the right and left vagus nerves lie against the esophagus, with fibers from both sides intermingling to form the esophageal plexus; they then emerge as the anterior and posterior vagal trunks and pass with the esophagus through the diaphragm via the esophageal hiatus into the abdominal cavity. At the heart, the right vagus nerve innervates the sinoatrial node and the left vagus nerve the atrioventricular node[^1].