December 1, 2013 Features

A Most Multi-talented Nerve

The vagus nerve performs a host of functions as it wanders throughout the body, many of them central to audiologists' and speech-language pathologists' work.

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An inexperienced speaker takes the stage. He squints into the spotlight, sensing an expectant audience out there in the dark. As stage fright tightens its grip, his throat goes dry and he feels short of breath. Dizziness leads to a queasy feeling in his stomach, and soon he's struggling to remember the opening words of his speech. Although this scenario seems like the outcome of a complicated interplay between many cranial nerves, in fact just one is at work: the vagus.

Cranial nerve X, also known as the vagus, is an intricate nerve that emerges from four different nuclei in the brainstem, each of which performs a distinct function. True to the meaning of the word's Latin base, it is a "wandering" nerve, the most widely distributed of the 12 cranial nerves. From its origin in the brainstem, it meanders throughout the head and neck to the thorax and abdomen, all the way to the colon, stimulating and receiving information from numerous muscles and organs along its path.

Many branches of the vagus nerve contain both sensory and motor fibers. As the fibers of the vagus exit the skull through an opening in the base, they synapse on two clusters of nerve cells, the superior and inferior ganglion. All branches of the vagus emerge from these two ganglia. The branches travel down the neck, nestled between the internal carotid artery and internal jugular vein. To add to the nerve's complexity, some branches of the vagus take different paths on the right and left sides of the body.

The vagus is classified as one of five branchiomeric cranial nerves. Together these nerves serve all the muscles and mucosa of the face and neck. These complex muscles control a range of functions including facial expression, speaking, chewing and swallowing. Although branches of the vagus extend into the thorax and abdomen—the esophageal, cardiac, pulmonary and gastrointestinal branches—we'll focus on the components most closely associated with audiologists' and speech-language pathologists' work. Let's take a tour and see where the vagus leads us: download and print the poster-sized vagus nerve chart [PDF], which illustrates the nerve's motor and sensory pathways that affect speech and hearing.

Melody Harrison, PhD, CCC-SLP, is professor and coordinator of master's studies in speech and hearing sciences at the University of North Carolina, Chapel Hill, where she teaches neuroanatomy. She is associate coordinator of ASHA Special Interest Group 9, Hearing and Hearing Disorders in Childhood. melody_harrison@med.unc.edu

cite as: Harrison, M. (2013, December 01). A Most Multi-talented Nerve. The ASHA Leader.

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