Phonatory effects of thyroid cartilage fractures.

Blunt trauma can cause a wide range of injuries to the cartilaginous framework of the larynx. The severity of injury that is required to cause a permanent disorder of vocal function if left untreated has not been defined. A study using excised canine and human larynges was undertaken to identify the effects of minimal displacement or malalignment in simulated thyroid cartilage fractures on selected voice production measurements. These fractures were found to cause changes in glottal configuration sufficient to affect glottal resistance as well as amplitude and noise content of the voice signal produced by each larynx. Therefore, relatively minor injuries of the thyroid cartilage may cause potentially serious disorders of phonation.