Abstract
The structure of sensory nerve endings of the human larynx has appeared in a few studies, however their role in the physiological function of the larynx, i. e. degulutition and protection of the upper respiratory organ, still has not been described in detail. This study was carried out to examine the structure of sensory nerve endings of the human laryngeal mucosa by means of light and electron microscopy and to discuss their relationship to the physiological function of the larynx. The results are summarized as follows; 1. In adults, sensory nerves and their endings are observed most frequently on the laryngeal surface of the epiglottis. 2. A comparatively large number of sensory endings are seen in the arytenoid region and false cord, although they are not as strongly developed as in the epiglottis. 3. Sensory nerve endings are very rarely seen in the vocal cords. 4. The types of sensory nerve endings observed in this study are free endings of simple or complex tree-like shape and corpuscle endings with glomerular patterns. 5. In the terminal portion, some varicosities of the axon or concentration of the terminal fibers are observed under the epithelium. Furthermore, very small varicosities of the fine terminal fibers are seen in the epithelium. 6. Using electron microscopy, nerve varicosities with an accumulation of mitochondria were observed. They partly lack the cytoplasm of Schwann cells and are in close contact with basal cells of the epithelium. No membrane specializations were observed between the basal epithelial cells and nerve varicosities. 7. In the newborn and infantile larynx a development of nerve fibers growing upward towards the epithelium are seen in the epiglottis, arytenoid region and false cord, how-ever it is not prominent in the vocal cords. 8. These nerve endings of the larynx seem very sensitive to any kind of stimulus and may be concerned with the degulutitive or protective function of the larynx.
