Nerve
Vagus nerve (CN X)
Mixed cranial pathways extending into chest and abdomen
High-yield
Vagal branches supply intrinsic laryngeal muscles and most palatal/pharyngeal muscles. The superior laryngeal external branch supplies cricothyroid; recurrent laryngeal branches supply the other intrinsic laryngeal muscles. Unilateral vagal weakness may lower the ipsilateral palate and deflect the uvula away.
Overview
The vagus combines branchial motor, parasympathetic and sensory pathways. Medullary motor output comes from nucleus ambiguus and dorsal vagal motor neurons; sensory axons connect with solitary and spinal trigeminal nuclei. After the jugular foramen, X descends in the carotid sheath and distributes branches to the pharynx, larynx, thorax and abdominal viscera.
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Reference facts
- Origin
- Branchial motor neurons in nucleus ambiguus; parasympathetic neurons in dorsal motor and ambiguus regions. Sensory somata lie in vagal ganglia and project chiefly to solitary and spinal trigeminal nuclei. Rootlets emerge behind the medullary olive.
- Skull exit
- Jugular foramen with IX and XI. The superior/jugular ganglion lies around the foramen; the inferior/nodose ganglion is below it.
- Course
- Descends between carotid artery and internal jugular vein. Right recurrent fibers loop below the subclavian artery and left below the aortic arch; both ascend toward the larynx. Thoracic plexuses reorganize into mainly left-derived anterior and right-derived posterior vagal trunks through the esophageal hiatus.
- Motor
- Most soft-palate/pharyngeal muscles, with tensor veli palatini supplied by V3 and stylopharyngeus by IX; intrinsic laryngeal and upper-esophageal muscles. Parasympathetic output reaches thoracic viscera and foregut/midgut organs, conventionally extending into proximal transverse colon, with peripheral ganglionic relays.
- Sensory
- Laryngopharyngeal and laryngeal sensation; parts of the external ear/canal and tympanic membrane; taste near the epiglottis; aortic baroreceptor/chemoreceptor and other thoracoabdominal visceral input.
Clinical correlation
Recurrent laryngeal injury can alter voice; bilateral dysfunction may compromise breathing, depending on vocal-fold position. Neck surgery and disease along the thoracic course are possible causes. Lateral medullary injury can impair swallowing and phonation. An ear-cough response occurs in some people through vagal auricular afferents.
Frequently asked questions
Where does the vagus nerve (CN X) arise?
Branchial motor neurons in nucleus ambiguus; parasympathetic neurons in dorsal motor and ambiguus regions. Sensory somata lie in vagal ganglia and project chiefly to solitary and spinal trigeminal nuclei. Rootlets emerge behind the medullary olive.
What muscles does the vagus nerve (CN X) supply?
Most soft-palate/pharyngeal muscles, with tensor veli palatini supplied by V3 and stylopharyngeus by IX; intrinsic laryngeal and upper-esophageal muscles. Parasympathetic output reaches thoracic viscera and foregut/midgut organs, conventionally extending into proximal transverse colon, with peripheral ganglionic relays.
What is the sensory distribution of the vagus nerve (CN X)?
Laryngopharyngeal and laryngeal sensation; parts of the external ear/canal and tympanic membrane; taste near the epiglottis; aortic baroreceptor/chemoreceptor and other thoracoabdominal visceral input.
Where does the vagus nerve (CN X) leave the skull?
Jugular foramen with IX and XI. The superior/jugular ganglion lies around the foramen; the inferior/nodose ganglion is below it.