Bulbar changes with laryngeal paralysis.
There are two hypotheses that attempt to explain how a lesion in the lower part of the chest may cause paralysis of both laryngeal nerves with intermediate position of the afflicted cord. The first proposes retrograde degeneration of the vagus nerve up to its nucleus ambiguus, the second, ascending metastasis along the vagus nerve until the superior laryngeal nerve becomes paralyzed. In one case of inoperable lung cancer, the brain-stem was sectioned into a gapless series. The number of cells of the nucleus ambiguus on each side was equal, thus excluding an irreversible retrograde degeneration. However, central chromatolysis was found more than twice as often on the side of laryngeal paralysis. Intermediate vocal cord position was again associated with paralysis of both laryngeal nerves of that side.
D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000150:complications / Q000473:pathology; D008526:Medulla Oblongata / Q000473:pathology*; D014630:Vagus Nerve / Q000473:pathology; D014826:Vocal Cord Paralysis / Q000209:etiology / Q000473:pathology*