The wandering nerve
Vagus nerve (X) · nervus vagus
The longest cranial nerve, wandering from your brainstem to your heart, lungs and gut.
What it does
The vagus nerve leaves the brainstem and runs down the neck beside the carotid artery into the chest and abdomen. It slows the heart, helps control breathing and the voice box, and runs much of the digestive system. Most of its fibres carry information back to the brain about how your organs are doing.
Surprising fact
Its name is Latin for "wandering", and around four in five of its fibres carry signals from the body to the brain, not the other way round.
Why it matters
Slow breathing, especially long out-breaths, boosts the calming effect of the vagus on the heart. A sudden surge of vagal activity is behind many simple faints.
Nearby
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Sources
Drafted with AI help; awaiting a human fact-check against these sources.
Open in the 3D atlas · Suggest a correction · Not medical advice.
3D models: Z-Anatomy & BodyParts3D (CC BY-SA 4.0 / 2.1 JP). Card text CC BY 4.0.