Vagus Nerve

Nervus vagus

For medical students2 min readUpdated 2026-10-10

The vagus nerve (CN X) is a mixed cranial nerve that provides the primary parasympathetic innervation to most thoracic and abdominal viscera. Descending from the brainstem to the abdominal cavity, it controls smooth muscle, glands, and cardiac function, as well as mediating visceral sensation.

OriginNuclei located in the medulla oblongata

CompositionSensory, motor, and autonomic (parasympathetic) fibers

Skull exitPasses through the jugular foramen

DistributionOrgans of the neck, thorax, and abdomen down to the left colic flexure

Nuclei of the Vagus Nerve

The central apparatus of the vagus nerve is represented by three nuclei located within the medulla oblongata:

Sensory nucleus (nucleus solitarius / nucleus of the solitary tract). This nucleus is shared with the glossopharyngeal and facial nerves. It receives taste and visceral sensory information, collecting input from internal organs.
Motor nucleus (nucleus ambiguus). This motor center is shared with the glossopharyngeal and accessory nerves. It gives rise to fibers that innervate the muscles of the pharynx, larynx, and soft palate.
Autonomic nucleus (nucleus dorsalis n. vagi / dorsal motor nucleus of the vagus). This is the parasympathetic center of the vagus nerve, serving as the origin for preganglionic parasympathetic fibers heading to thoracic and abdominal viscera.

Topography and Skull Exit

The pathway of the vagus nerve begins on the ventrolateral surface of the brainstem. It emerges via several rootlets from the medulla oblongata just posterior to the olive. The nerve trunk then courses toward the jugular foramen to exit the cranial cavity. In this region, the nerve bears two important sensory ganglia: the superior ganglion (ganglion superius) and the inferior ganglion (ganglion inferius).

Upon exiting the skull, the nerve descends through the neck within the carotid sheath, accompanied by the internal jugular vein and internal/common carotid artery. Leaving the cervical region, the trunk enters the thorax and eventually continues into the abdominal cavity, where it forms two major plexuses: the anterior and posterior vagal trunks (trunci vagales).

Cervical Branches

In the cervical region, multiple branches arise from the trunk to innervate structures of the head and neck:

Meningeal branch (r. meningeus) and auricular branch (r. auricularis).
Communicating branches connecting the nerve to the sympathetic trunk and glossopharyngeal nerve.
Pharyngeal branches, which contribute to the formation of the pharyngeal plexus (plexus pharyngeus).
Superior laryngeal nerve (n. laryngeus superior). It divides into an external branch (r. externus), which is motor, and an internal branch (r. internus), which is sensory.
Recurrent laryngeal nerve (n. laryngeus recurrens). It has an asymmetric course: on the left, it loops under the aortic arch; on the right, it loops under the subclavian artery. It gives off tracheal branches (rr. tracheales) and esophageal branches (rr. esophagei). Its terminal portion is the inferior laryngeal nerve (n. laryngeus inferior), which innervates the laryngeal mucosa below the vocal folds and all intrinsic muscles of the larynx (except the cricothyroid muscle — m. cricothyroideus).

Thoracic and Abdominal Branches

In the thoracic cavity, the n. vagus gives off thoracic cardiac branches (rr. cardiaci thoracici) and bronchial branches (rr. bronchiales). Fibers from these branches actively participate in forming major autonomic plexuses: the cardiac plexus (plexus cardiacus), pulmonary plexus (plexus pulmonalis), and esophageal plexus (plexus oesophageus).

In the abdomen, the anterior and posterior vagal trunks become the primary structures. Here, they innervate the stomach, liver, pancreas (via fibers passing through the celiac plexus), and intestines. The zone of parasympathetic innervation of the gut terminates at the level of the left colic flexure (splenic flexure).

A key feature of the vagus nerve is that its preganglionic parasympathetic fibers pass through all autonomic plexuses in transit. Synapse with postganglionic neurons occurs exclusively intramurally — directly within the walls of the innervated organs of the neck, thorax, and abdomen.

Frequently asked questions

Which specific laryngeal muscles are innervated by the recurrent laryngeal nerve?

The recurrent laryngeal nerve is the primary motor nerve of the larynx and innervates all intrinsic muscles of the larynx, with the sole exception of the cricothyroid muscle.

Intrinsic laryngeal muscles (musculi laryngis) — all laryngeal muscles except the cricothyroid muscle

Which nerves participate in forming the pharyngeal plexus alongside the vagus nerve?

The pharyngeal plexus is formed by contributions from the vagus nerve, glossopharyngeal nerve, and sympathetic trunk fibers.

Glossopharyngeal nerve (n. glossopharyngeus) — contributes to the pharyngeal plexus
Sympathetic trunk (truncus sympathicus) — contributes fibers to the pharyngeal plexus

Which muscle is innervated by the external branch of the superior laryngeal nerve?

The external branch of the superior laryngeal nerve is motor and innervates the cricothyroid muscle.

Cricothyroid muscle (m. cricothyroideus) — innervated by the motor external branch

What structures are innervated by the auricular branch of the vagus nerve?

The auricular branch of the vagus nerve innervates the skin of the posterior-inferior part of the external acoustic meatus and the posterior surface of the auricle. This is the only cutaneous branch of the vagus nerve.

Skin of the external acoustic meatus — posterior-inferior surface
Skin of the auricle — posterior surface

With which cranial nerves does the vagus nerve share nuclei?

The vagus nerve shares sensory and motor nuclei with the glossopharyngeal nerve, as well as a motor nucleus with the accessory nerve. The nucleus of the solitary tract is shared with the glossopharyngeal nerve, and the nucleus ambiguus is shared with the glossopharyngeal and accessory nerves.

Glossopharyngeal nerve (n. glossopharyngeus, CN IX) — shares the nucleus of the solitary tract and nucleus ambiguus
Accessory nerve (n. accessorius, CN XI) — shares the nucleus ambiguus

Where are the nuclei of the vagus nerve located?

All three nuclei of the vagus nerve (sensory, motor, and parasympathetic) are located in the medulla oblongata. Two of these are shared with other lower cranial nerves.

How does the recurrent laryngeal nerve course on the right versus the left side?

On the left, it descends into the thorax and loops under the aortic arch, whereas on the right, it loops under the right subclavian artery, after which both nerves ascend back toward the larynx.

Where are the postganglionic parasympathetic neurons located?

Postganglionic neurons of the vagus nerve are located intramurally—embedded directly within the walls of the target visceral organs.

To what level of the gastrointestinal tract does the vagus nerve provide parasympathetic innervation?

Its parasympathetic innervation extends along the gastrointestinal tract up to the left colic (splenic) flexure of the colon.

Go deeper

Participation of the vagus nerve in forming the cardiac plexus (plexus cardiacus).
Anatomy and topography of the anterior and posterior vagal trunks (trunci vagales).
Structure, connections, and functions of the pharyngeal plexus (plexus pharyngeus).
Mechanism of neural transmission in intramural organ ganglia.
Innervation details of laryngeal muscles by branches of the superior and recurrent laryngeal nerves.