The vagus nerve is the longest cranial nerve, extending from the brainstem through the neck into the chest and abdomen.
Also called cranial nerve X, it is a major part of the parasympathetic nervous system. Its branches influence the heart, lungs, and much of the digestive tract, helping regulate functions such as heart rate, breathing-related activity, and digestion.
The name “vagus” comes from Latin for “wandering,” reflecting its long route through the body. It leaves the skull through the jugular foramen and travels alongside major structures in the neck before branching widely in the thorax and abdomen.
The vagus nerve is not the same as the spinal accessory nerve, which is also involved in neck and shoulder movement. Nor is it the optic nerve, which carries visual information from the eye to the brain.