Nuclei of the vagus nerve
The central apparatus of the vagus nerve is represented by three nuclei localized within the medulla oblongata:
- Sensory nucleus (nucleus solitarius). This nucleus is shared with the glossopharyngeal nerve. It is responsible for the perception of gustatory and visceral sensation, collecting information from internal organs.
- Motor nucleus (nucleus ambiguus). This motor center also shares its functions with the glossopharyngeal nerve. It gives rise to impulses that innervate the muscles of the pharynx, larynx, and soft palate.
- Autonomic nucleus (nucleus dorsalis n. vagi). This is the parasympathetic center of the vagus nerve. It serves as the starting point for parasympathetic fibers heading to the thoracic and abdominal organs.
Topography and skull exit
The topography of the vagus nerve begins on the inferior surface of the brain. It emerges via several rootlets arising from the medulla oblongata just posterior to the olive. Afterward, the nerve trunk heads toward the jugular foramen to leave the cranial cavity. In this region, two important sensory ganglia are located on the nerve: the superior ganglion (ganglion superius) and the inferior ganglion (ganglion inferius).
Having left the skull, the nerve begins its descent. In the neck, it runs within the main neurovascular bundle. Bypassing the cervical region, the trunk enters the thoracic cavity and then continues into the abdominal cavity, where it forms two large plexuses — the anterior and posterior vagal trunks (trunci vagales).
Branches of the cervical region
In the cervical region, multiple branches depart from the trunk, responsible for innervating structures of the head and neck:
- Meningeal branch (r. meningeus) and auricular branch (r. auricularis).
- Communicating branches connecting the nerve with the sympathetic trunk and the glossopharyngeal nerve.
- Pharyngeal branches participating in the formation of the pharyngeal plexus (plexus pharyngeus).
- Superior laryngeal nerve (n. laryngeus superior). It divides into the external branch (r. externus), which performs a motor function, and the internal branch (r. internus), which is responsible for sensation.
- Recurrent laryngeal nerve (n. laryngeus recurrens). It has an asymmetrical course: on the left side, it loops around the aortic arch, and on the right side, around the subclavian artery. It gives off tracheal branches (rr. tracheales) and esophageal branches (rr. esophagei). Its terminal part is the inferior laryngeal nerve (n. laryngeus inferior), which innervates the mucous membrane below the rima glottidis and the laryngeal muscles (except for the cricothyroid muscle — m. cricothyroideus).
Branches of the thoracic and abdominal regions
In the thoracic cavity, the n. vagus gives off thoracic cardiac branches (rr. cardiaci thoracici) and bronchial branches (rr. bronchiales). The fibers of 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 abdominal region, the anterior and posterior vagal trunks become the main structures. In this zone, they innervate the stomach, liver, pancreas (fibers pass through the celiac plexus), and intestines. The zone of parasympathetic innervation of the intestines ends at the level of the left half of the colon.
The main feature of the vagus nerve is that its preganglionic parasympathetic fibers pass through all autonomic plexuses in transit. Switching to postganglionic neurons occurs exclusively intramurally — that is, directly in the walls of the innervated organs of the neck, thorax, and abdomen.
Briefly: answers to topical questions
Which specific laryngeal muscles are innervated by the recurrent laryngeal nerve?
The recurrent laryngeal nerve is the main motor nerve of the larynx and innervates all of its intrinsic muscles, except for the cricothyroid muscle. The only exception is the cricothyroid muscle, which it does not innervate.
- Muscles of the larynx (musculi laryngis) — all laryngeal muscles except the cricothyroid muscle
Which nerves participate in the formation of the pharyngeal plexus along with the vagus nerve?
The glossopharyngeal nerve and fibers of the sympathetic trunk participate in the formation of the pharyngeal plexus along with the vagus nerve. The pharyngeal branches of the vagus nerve accompany fibers of the glossopharyngeal nerve and the sympathetic trunk.
- Glossopharyngeal nerve (n. glossopharyngeus) — participates in the formation of the pharyngeal plexus
- Sympathetic trunk (truncus sympathicus) — participates in the formation of the pharyngeal plexus with its fibers
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. This branch departs from the superior laryngeal nerve and proceeds toward the specified muscle.
- Cricothyroid muscle (m. cricothyroideus) — innervated by the motor external branch
Which structures does the auricular branch of the vagus nerve innervate?
The auricular branch of the vagus nerve innervates the skin of the posteroinferior surface of the external acoustic meatus and the posterior surface of the auricle. This branch is the only cutaneous branch of the vagus nerve.
- Skin of the external acoustic meatus — skin of the posteroinferior surface
- Skin of the auricle — skin of the posterior surface
With which cranial nerves does the vagus nerve share common nuclei?
The vagus nerve shares sensory and motor nuclei with the glossopharyngeal nerve, as well as a motor nucleus with the accessory nerve. The sensory 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, IX pair) — shares the nucleus of the solitary tract and the nucleus ambiguus
- Accessory nerve (n. accessorius, XI pair) — shares the nucleus ambiguus
Class and exam questions
Where are the nuclei of the vagus nerve located?
All three nuclei of the vagus nerve (sensory, motor, and parasympathetic) are localized in the medulla oblongata. Two of them are shared with the glossopharyngeal nerve.
How does the recurrent laryngeal nerve run on the right and left sides?
On the left, it descends lower and loops around the aortic arch, while on the right, it loops over the subclavian artery, after which both nerves ascend back toward the larynx.
Where are postganglionic parasympathetic neurons located?
Postganglionic neurons of the vagus nerve are located intramurally — they lie directly within the walls of the innervated internal organs.
Up to what level does the vagus nerve innervate the intestines?
Its zone of innervation extends to the gastrointestinal tract up to the left half (left flexure) of the colon.
What else to study on this topic
- Participation of the vagus nerve in the formation of 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 nerve impulse transmission in intramural ganglia of organs.
- Features of laryngeal muscle innervation by branches of the superior and recurrent laryngeal nerves.
Study the complete topic in the Anatomy course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on the "Vagus nerve" and 1,363 other subject pages
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 295 video lessons by subject
Other topics in the "PNS" section
Free video lessons: AnatomyShort lessons with study notes — no registration required.
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.