Quick Facts
Origin: Inferior ganglion of vagus nerve.
Course: Run inferiorly and slightly medially, between the external and internal carotid arteries to reach the posterior surface of the middle pharyngeal constrictor muscle.
Branches: Contributes to pharyngeal plexus.
Supply: Sensory, motor, and parasympathetic information to and from the pharynx, palate, and fauces.
Related parts of the anatomy
Origin
The pharyngeal branches of the vagus nerve originate from the inferior ganglion of the vagus nerve. Efferent fibers originate in the dorsal nucleus of vagus nerve and the nucleus ambiguus of the medulla oblongata. The cell bodies for afferent fibers are located in the inferior ganglion of the vagus nerve.
Some sources consider motor fibers to the pharynx to be cranial fibers of the accessory nerve which join the vagus nerve at the inferior ganglion and travel with vagus nerve branches, such as the pharyngeal branches. It is the author’s view that these branchial motor fibers which originate in the nucleus ambiguus are in fact vagal fibers, and they merely travel with the accessory nerve temporarily before rejoining the vagus nerve (Shoja et al., 2014).
Course
From its origin at the inferior ganglion, the pharyngeal branches run inferiorly and medially, coursing between the external and internal carotid arteries to reach the posterior surface of the middle constrictor muscle.
Branches
There are no named branches; however, the pharyngeal branches will mix with sympathetic fibers and fibers of the glossopharyngeal nerve to form the pharyngeal plexus.
Supplied Structures
The pharyngeal branches of the vagus nerve are mixed nerves that convey sensory, motor, and parasympathetic innervation to a range of targets.
The sensory fibers are general visceral fibers that convey sensation from two major areas: the mucosa of the upper oral tract, including palate, pharynx, and fauces, and chemo-sensory fibers from the carotid branches and carotid plexus. Special visceral taste fibers convey taste sensation from the few taste receptors in the epiglottis and surrounding tissues.
The motor fibers are branchial motor efferents that innervate all the muscles of the pharynx, except the stylopharyngeus muscle, and all the muscles of the palate, except tensor veli palatini muscle.
The parasympathetic fibers target smooth muscle and glandular tissue in the fauces, epiglottis, palate, and pharynx.
References
Shoja, M. M., Oyesiku, N. M., Shokouhi, G., Griessenauer, C. J., Chern, J. J., Rizk, E. B., Loukas, M., Miller, J. H. & Tubbs, R. S. (2014) A comprehensive review with potential significance during skull base and neck operations, Part II: Glossopharyngeal, vagus, accessory, and hypoglossal nerves and cervical spinal nerves 1–4. Clinical Anatomy, 27(1), 131-144.
