ULTRASTRUCTURE OF THE LAMINA PROPRIA OF THE HUMAN VOCAL FOLD

We studied three-dimensional arrangement of collagen fibers and elasti c fibers in the human vocal fold by scanning electron microscopy after digesting cellular elements and collagen fibers with formic acid trea tment and cellular elements and elastic fibers with 10% sodium hydroxi de. The superficial layer consisted of clusters of collagen fibers and fine elastic fibers running straight or coiled. The intermediate laye r consisted of thick bundles of collagen and elastic fibers running lo ngitudinally and fine coiled elastic fibers. The deep layer consisted of coil Elastic libers and dense collagen bundles. Collagen fibers may have a role of maintaining the organization of vocal folds even durig vibration, and elastic fibers act to rapidly restore the vocal folds to their original form. We also studied the distribution of oxytalan f ibers in vocal folds by aldehyde-fucusin staining. Oxytalan fibers wer e distributed throughout the connective tissue of the vocal folds, and a large number of fibers was resent just under the epithelial basemen t membrane and around the muscle fibers. If these fibers are damaged a nd lose their functions, vibration of the vocal folds will be impaired .