Structure and Development - Neurons in the superior ganglion of the vagus nerve are pseudounipolar. - The neurons provide sensory innervation through either the auricular or meningeal branch. - The axons of these neurons synapse in the spinal trigeminal nucleus. - The superior ganglion contains neurons that form two branches, the auricular and meningeal branch. - Peripherally, the neurons innervate the concha of the auricle, the posteroinferior surface of the external auditory canal, and posteroinferior surface of the tympanic membrane. - The neurons in the superior ganglion of the vagus nerve are embryonically derived from the neural crest. - The neural crest can be seen in light green during embryonic development of the nervous system.

Function - The superior ganglion contains neurons that innervate the concha of the auricle. - Neurons in the superior ganglion innervate the posteroinferior surface of the external auditory canal. - The posteroinferior surface of the tympanic membrane is innervated by neurons in the superior ganglion. - Innervation of these structures is carried out via the auricular branch of the vagus nerve. - Some of the dura mater lining the posterior cranial fossa is innervated by neurons in the superior ganglion through the meningeal branch of the vagus nerve.

Clinical significance - Vagal neuralgia can cause pain in the external auditory canal (otalgia) due to vascular compression of the vagus nerve. - The affected neurons in the superior ganglion innervate the ear via the auricular branch of the vagus nerve. - Microvascular decompression of the vagus nerve is used to treat vagal neuralgia. - Vagal neuralgia is often caused by compression from the posterior inferior cerebellar artery.

References - Rubin, Michael (2016). Netters Concise Neuroanatomy. - Burt, Alvin M. (1993). Textbook of Neuroanatomy. - Mercante B, Ginatempo F, Manca A, Melis F, Enrico P, Deriu F (June 2018). Anatomo-Physiologic Basis for Auricular Stimulation. - Tekdemir I, Aslan A, Elhan A (1998). A clinico-anatomic study of the auricular branch of the vagus nerve and Arnolds ear-cough reflex. - Watanabe, Kentaro; Tubbs, R. Shane; Satoh, Shunsuke; Zomorodi, Ali R.; Liedtke, Wolfgang; Labidi, Moujahed; Friedman, Allan H.; Fukushima, Takanori (December 2016). Isolated Deep Ear Canal Pain: Possible Role of Auricular Branch of Vagus Nerve-Case Illustrations with Cadaveric Correlation.

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