The recurrent laryngeal nerves innervate all the laryngeal muscles, with the exception of the cricothyroid. Isolated vagal palsy can be central or peripheral, due to complete vagal nerve dysfunction or isolated impairment of the recurrent laryngeal nerve, respectively. Lesions proximal to the pharyngeal branches cause ipsilateral palatal weakness. Because lesions anywhere along the course of the vagus nerve may potentially cause vocal cord paralysis, Cranial Neuropathy the imaging protocol must visualize the full extent of the nerve from the skull base to the mid chest in this situation [2,152]. In the case of a central palsy, careful neurologic examination and patient history may help to locate the lesion to the central nervous system. Intramedullary lesions that can affect the vagus nucleus include demyelination, infarction, neoplasms, motor neuron disorders, and syringobulbia. Intracranial processes such as meningiomas, schwannomas, metastases, granulomatous disease, and infection may affect the nerve as it exits the medulla. Paragangliomas, schwannomas, meningiomas, and metastases involving the skull base may affect the vagus nerve and the neighboring glossopharyngeal nerve (CN IX) or accessory nerve (CN XI) by infiltration of fibers or by compression [2,152,153]. Direct and indirect signs of vocal cord paralysis can be seen on CT [152]. Optimal evidence-based imaging algorithms in the setting of unilateral vocal cord paralysis without an apparent cause are not established. One of the most troubling symptoms of vagus dysfunction is vocal cord paralysis. Injury of the recurrent laryngeal branch in the neck or upper thorax can be idiopathic, due to iatrogenic injury from surgery or intubation, trauma, infection, inflammation, vascular lesions, and neoplasms arising in the neck and thorax. Moreover, thoracic causes of vocal cord paralysis, such as lung cancer, tuberculosis, and thoracic aortic aneurysm, are common [154-157].
Cranial Neuropathy. The recurrent laryngeal nerves innervate all the laryngeal muscles, with the exception of the cricothyroid. Isolated vagal palsy can be central or peripheral, due to complete vagal nerve dysfunction or isolated impairment of the recurrent laryngeal nerve, respectively. Lesions proximal to the pharyngeal branches cause ipsilateral palatal weakness. Because lesions anywhere along the course of the vagus nerve may potentially cause vocal cord paralysis, Cranial Neuropathy the imaging protocol must visualize the full extent of the nerve from the skull base to the mid chest in this situation [2,152]. In the case of a central palsy, careful neurologic examination and patient history may help to locate the lesion to the central nervous system. Intramedullary lesions that can affect the vagus nucleus include demyelination, infarction, neoplasms, motor neuron disorders, and syringobulbia. Intracranial processes such as meningiomas, schwannomas, metastases, granulomatous disease, and infection may affect the nerve as it exits the medulla. Paragangliomas, schwannomas, meningiomas, and metastases involving the skull base may affect the vagus nerve and the neighboring glossopharyngeal nerve (CN IX) or accessory nerve (CN XI) by infiltration of fibers or by compression [2,152,153]. Direct and indirect signs of vocal cord paralysis can be seen on CT [152]. Optimal evidence-based imaging algorithms in the setting of unilateral vocal cord paralysis without an apparent cause are not established. One of the most troubling symptoms of vagus dysfunction is vocal cord paralysis. Injury of the recurrent laryngeal branch in the neck or upper thorax can be idiopathic, due to iatrogenic injury from surgery or intubation, trauma, infection, inflammation, vascular lesions, and neoplasms arising in the neck and thorax. Moreover, thoracic causes of vocal cord paralysis, such as lung cancer, tuberculosis, and thoracic aortic aneurysm, are common [154-157].