The vagus nerve (cranial nerve X) leaves the side of the medulla oblongata as a row of rootlets between the olive and the inferior cerebellar peduncle, exits the skull through the jugular foramen and runs down the neck inside the carotid sheath into the chest and abdomen. It is the longest nerve of the autonomic nervous system, linking the brain with the heart, lungs and gut. [1]
The 3D brain needs JavaScript. The text below still says where the vagus nerve is and what it does.
Opens cut by a side (sagittal) slice through the medulla oblongata, which the vagus nerve leaves the brain from. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
Not a separate shape in this atlas; lit: the part it leaves the brain from. Lit: the whole medulla oblongata, the part the vagus nerve leaves the brain from. The nerve itself, which runs on down through the neck, chest and abdomen, has no shape in the BodyParts3D model, so nothing is drawn for it at a guessed point. [2][1]
Where it leaves the brain: the medulla oblongata. Its rootlets come out of the side of the medulla, behind the olive and in front of the inferior cerebellar peduncle, in the same row as the glossopharyngeal (IX) and accessory (XI) rootlets. [1][3]
Lit here: the medulla oblongata, the part the vagus nerve leaves the brain from — see it on its own page.
Its fibres start or end in four nuclei of the medulla: the dorsal nucleus of the vagus, the nucleus ambiguus, the solitary nucleus and the spinal trigeminal nucleus. [1]
It leaves the skull through the jugular foramen, the same opening as the glossopharyngeal (IX) and accessory (XI) nerves. [1][4]
In the neck it runs down inside the carotid sheath, between the internal carotid artery and the internal jugular vein, then on into the chest and abdomen, reaching as far as the colon. [1]
There is one on each side. The right vagus runs down behind the right main bronchus, the left one over the arch of the aorta; both break up around the oesophagus and pass through the diaphragm with it, the right as the posterior vagal trunk and the left as the anterior vagal trunk. [1]
What it does
It is the main parasympathetic nerve: its output reaches every organ from the neck down to the transverse colon except the adrenal glands, and helps set the heart rate, breathing and the movements of the gut (peristalsis), the body’s “rest and digest” side. [1][5]
Most of its fibres, about 80 to 90 per cent, are sensory: they carry information on the state of the organs of the chest and abdomen up to the brainstem. [1]
It works the muscles of the soft palate, throat and voice box (larynx) used in swallowing and speech; the larynx is reached through its recurrent laryngeal branches. [1]
Its auricular branch carries feeling from the inner part of the outer ear, and its signals from the gut take part in feeling full after a meal. [1]
Connections
From the brain: output fibres from the dorsal nucleus of the vagus and the nucleus ambiguus in the medulla. Into the brain: sensory fibres whose cell bodies sit in two swellings of the nerve just below the skull, the jugular (superior) and nodose (inferior) ganglia. [1]
The right recurrent laryngeal nerve hooks round the right subclavian artery and the left one round the arch of the aorta; both climb back up to the larynx between the windpipe and the oesophagus. [1]
Other names
Cranial nerve X (CN X), tenth cranial nerve; nervus vagus (Latin). “Vagus” is Latin for wandering, after its long course; the two together are the vagi. It was once called the pneumogastric nerve, since it supplies both the lungs and the stomach. [1]
Size
The model has no shape for the vagus nerve, so it is not measured here. The medulla oblongata, lit as the part it leaves the brain from, measures about 33 mm front to back, 41 mm top to bottom and 27 mm side to side on this model (the box it fits in, not its volume). [2]
Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain.