Ventrolateral view, right side

Ventrolateral view, left side

The vagus nerve is cranial nerve X.  It is the only cranial nerve to pass into the body cavities below the neck.  It is primarily parasympathetic in nature and is the major nerve affecting the heart and most of the gastrointestinal tract. It slows the heart down and speeds up the activity of the gastrointestinal tract.  As the left and right vagus nerves approach the heart they run parallel to the respective phrenic nerves.  After leaving the heart they reorganize as ventral and dorsal vagus nerves that run along the esophagus to and through the diaphragm.  Spelling counts on this nerve, be sure to spell vagus correctly!