Vagus nerve (CN X)
After working through this study unit you will be able to:
- Describe the structure, course and relations of the vagus nerve.
- Discuss the branches and functional pathways of the vagus nerve.
- List the associated nuclei of this nerve.
The vagus nerve (CN X) is the longest cranial nerve, and as its name suggests (Latin = wandering nerve), has an extensive course and wide distribution in the body, traversing the neck, thorax and abdomen. It is a mixed nerve, whose functions include:
- general somatic afferent (GSA, sensory) innervation of the laryngopharynx, larynx and root of the tongue
- special visceral afferent (SVA, taste) innervation of the root of the tongue and epiglottal taste buds
- general visceral afferent (GVA, sensory) innervation of thoracic and abdominal organs
- general visceral efferent (GVE, parasympathetic) innervation to thoracoabdominal organs
- special visceral efferent (SVE, branchiomotor) innervation to the palatoglossus muscle of the tongue and several muscles of the soft palate, pharynx and larynx
The vagus nerve arises from the lateral aspect of the medulla oblongata and exits the cranial cavity through the jugular foramen. From here, each vagus nerve descends through the neck, providing innervation to the palate, pharynx, and larynx along the way, before continuing into the thorax to innervate the heart, bronchi, and lungs. The right and left vagus nerves intermingle around the esophagus before going on to form the posterior and anterior vagal trunks which subsequently pass into the abdomen to supply abdominal viscera of the foregut and midgut (i.e. stomach as far as the left colic flexure of large intestine) and other abdominal organs (liver, spleen, pancreas etc.).
This video will help you learn more about the vagus nerve.
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Take a look at our atlas gallery to further review the course, distribution and supply of the vagus nerve more detail.
Fiber types: General somatic afferent (GSA), special visceral afferent (SVA), general visceral afferent (GVA), general somatic efferent (GSE), general visceral efferent (GVE)
Origin: Medulla oblongata
Motor nuclei: Nucleus ambiguus (SVE), dorsal vagal nucleus (GVE)
Sensory nuclei: Spinal nucleus of trigeminal nerve (GSA), nucleus of solitary tract (GVA/SVA)
Associated ganglia: Superior and inferior ganglia of CN X
Jugular fossa: Meningeal, auricular branches
Neck: Pharyngeal, superior laryngeal, recurrent laryngeal nerve (right only); superior/inferior cervical cardiac branches
Thorax: Recurrent laryngeal nerve (left only), thoracic cardiac branches, bronchial branches, esophageal branches
Abdomen: Posterior vagal trunk (posterior gastric, celiac, renal branches), anterior vagal trunk (anterior gastric branches, hepatic, pyloric branches), intestinal branches (up to left colic flexure)
General somatic afferent (GSA): Larynx, laryngopharynx, part of the external acoustic meatus, and dura mater of
posterior cranial fossa
General visceral afferent (GVA): Aortic body chemoreceptors/aortic arch baroreceptors, esophagus, bronchi, lungs, heart, and abdominal viscera of foregut and midgut
Special visceral afferent (SVA): Taste from root of tongue and epiglottis
General somatic efferent (GSE): Palatoglossus muscle, muscles of soft palate (except tensor veli palatini), muscles of pharynx (except stylopharyngeus) and muscles of larynx
General visceral efferent (GVE): Parasympathetic/secretomotor fibres to smooth muscle and glands of the pharynx and larynx, parasympathetic innervation of thoracic viscera, and abdominal viscera of the foregut and midgut