Sonography of the Cervical Vagus Nerve: Normal Appearance and Abnormal Findings

The purpose of this study was to assess the appearance of the cervical vagus nerve in healthy individuals and to investigate the potential role of sonography in revealing neck masses that cause vagal dysfunction. We examined 150 consecutive patients. In 144 patients the presence of thyroid, salivary gland, or lymph node disease was suspected. In three patients a cervical mass was palpable, and three patients had symptoms of dysfunction of the inferior laryngeal or vagal nerves. The pathologic diagnoses of the masses were obtained at biopsy. In 144 individuals the normal vagus nerve was recognized on each side of the neck as a thin band that occupied the posterior angle formed by the common carotid artery and the internal jugular vein. Three patients had tumors arising from the vagus nerve: one neurofibroma, one neurinoma, and one chemodectoma. These tumors were located in the neurovascular bundle and posterior to the vessels; their origin from the vagus nerve was clearly visible in all patients because of the contiguity of the mass with the nerve bundle. In the other three patients, sonography revealed an extrinsic mass that compressed and displaced the vagus nerve out of its longitudinal axis; two cases were hyperplastic nodules of the thyroid, and in one case the nodule was a branchial cyst. Sonography can reveal the vagus nerve in healthy conditions and correctly reveal the vagal origin of some tumors in the parapharyngeal spaces.