The human larynx plays a pivotal role in airway protection, respiration, and phonation. Most patients with benign laryngeal disorders present with dysphonia. These disorders are particularly prevalent in individuals who use their voices professionally. Malignant neoplastic disease should be excluded as an underlying cause of voice problems: Every patient who presents with dysphonia should undergo a thorough head and neck examination. Once it is established that there is no evidence of malignancy, patients can be treated appropriately, ideally within a voice clinic. A properly equipped voice clinic must have access to video-laryngeal-stroboscopy and be conducted with a suitably qualified speech-language pathologist.
The diagnosis should include a thorough appreciation of the patient’s lifestyle and occupational habits as well as a detailed examination of the vocal folds including stroboscopy. Most benign laryngeal lesions are treatable with a combination of surgery and speech therapy, but measures to prevent the recurrence of disease by instigating and maintaining lifestyle changes are also necessary.
The larynx consists of a cartilaginous framework composed of the thyroid, cricoid, and epiglottis cartilages and the paired arytenoid, corniculate, and cuneiform cartilages. It is suspended from the hyoid bone by the thyrohyoid membrane. The vocal folds run from the angle formed by the thyroid lamina anteriorly to the vocal process of the arytenoid cartilages posteriorly. Alteration in the position and length of the vocal folds is primarily the result of movement of the synovial cricoarytenoid joints, with a contribution from movement of the cricothyroid joints. Above the vocal folds run the false cords, formed by the medial border of the aryepiglottic folds. These are separated from the vocal folds by horizontal sinus known as the laryngeal ventricle, which contains numerous mucin-secreting glands.
The vocal folds are covered with a stratified squamous epithelium that has up to 20 layers; this epithelium covers the lamina propria, which has 3 layers, beneath which lies the vocal ligament and vocalis muscle. Loose collagen cross-linkages between the epithelium and the superior layer of the lamina propria (ie, Reinke space) allow oscillation of the mucosal wave during phonation as the epithelium is able to glide over Reinke space.
When expiration occurs against a closed glottis, pressure is created in the subglottis. This air passes between the adducted vocal folds and through the Bernoulli effect causes vibration of the mucosa of the vocal folds, producing sound. Abnormalities preventing full adduction of the vocal folds or affecting vibration of the mucosa produce dysphonia. Dysphonia is altered voice quality, pitch, loudness, or vocal effort that impairs communication or decreases voice-related quality of life.
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