Histopathologic investigations of the unphonated human vocal fold mucosa

CONCLUSION: Vocal fold vibration (phonation) after birth is one of the important factors in the growth and development of the human vocal fold mucosa. OBJECTIVES: Stellate cells in the maculae flavae located at both ends of the vocal fold mucosa are inferred to be involved in the metabolism of extracellular matrices. Maculae flavae are also considered to be an important structure in the growth and development of the human vocal fold mucosa. Tension caused by phonation (vocal fold vibration) is hypothesized to stimulate stellate cells to accelerate production of extracellular matrices. Vocal fold mucosae unphonated since birth were investigated histologically. SUBJECTS AND METHODS: Vocal fold mucosae, which were unphonated since birth, of three younger adults (17, 24, 28 years old) were investigated by light and electron microscopy. RESULTS: Vocal fold mucosae were hypoplastic and rudimentary and did not have a vocal ligament, Reinke's space or a layered structure. The lamina propria appeared as a uniform structure. Some stellate cells in the maculae flavae showed degeneration. Not many vesicles were present at the periphery of the cytoplasm. The stellate cells synthesized fewer extracellular matrices, such as fibrous protein and glycosaminoglycan. Cytoplasmic processes of the stellate cells were short and shrinking. The stellate cells appeared to have decreased activity.