HNO
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The morphological development of the human larynx during the first years of life has previously not been studied in detail and has mainly been described on a qualitative basis. This study seeks to provide detailed morphometric data on the regular anatomy of the vocal cords, the subglottic airway and the tracheal airway dimensions gained from plastinated whole organ serial sections of 43 infant larynges and to determine morphological changes with age. Such information may be useful for the understanding of pediatric airway disease or for laryngeal surgery in children. ⋯ This study supplies detailed morphometric data on the growth and structure of the human larynx during the first years of life that have not been available to date. Previous studies on the anatomical configuration of the infant larynx have focused on the the perinatal larynx, the prepuberal and puberal larynx, and the development of collagen fibres in the developing larynx. The human larynx has undergone significant evolutionary adaptations. Among them are the descent of the larynx, the capability of vocal fold adjustment in length, tension and shape, and the prominent configuration of the membranous part of the vocal folds as opposed to the cartilaginous part. The infant larynx is not just a miniature of the adult organ. It shows differences in its position relative to the vertebrate column, in the composition of cartilages and soft tissues, and in environmental adaptation. The present study is the first to supply detailed morphometric data on the growth and structure of the human larynx during the first five years of life and on the morphological changes of the larynx during this period. From these data it seems that some of the adaption of the human larynx as opposed to other vertebrates are not fully developed at birth, but undergo postnatal maturation. The relative proportions of the cartilaginous and membranous parts of the vocal folds clearly demonstrate this maturation process: While the posterior "respiratory" glottis accounts for some sixty to 75% of the total glottic length in newborns, its relative proportion decreases throughout the first years of life and finally equals the proportions of the adult larynx. Other than in adults, and in accordance with the literature, no sexual dimorphism of the larynx could be detected in this series of infant larynges. Morphometric data on the growth and structure of the human vocal folds and the subglottic airway during childhood are presented. Plastinated whole organ serial sections were used in the study to show the infant laryngeal morphology. The study provides quantitative anatomical data of clinical interest that light up the anatomy of the pediatric airways.
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The osteoplastic frontal sinus surgery with obliteration of the sinus has been established in the therapy of frontal sinus diseases that can not be drainaged permanently or healed through an endonasal access. The obliteration of the frontal sinus is endangered in cases of multiple fracturing of the posterior frontal sinus wall or if it has been destroyed by an inflammatory process. In these problematic cases obliteration bears the danger of complications and cranialization of the frontal sinus is therefore the method of choice. ⋯ The overall functional and esthetic outcome was excellent. There were no serious complications nor any recurrence. The cranialization of the frontal sinus is a reliable and safe variation of the classical osteoplastic frontal sinus surgery with fat obliteration.
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Sound overexposure is known to cause damage to cochlear structures and can induce permanent or temporary hearing loss and tinnitus. Perhaps the most sensitive of these structures to sound overexposure are the tip links. In this paper the electrophysiological effects of pharmacological destruction of the tip links of outer hair cells was investigated. ⋯ In contrast to common belief, transduction channels opened due to loss of tip links. Such opened channels can allow K+ and Ca2+ to enter the cell from the endolymphatic space and cold lead to permanent depolarization. This influx of cations caused by loss of tip links, together with the subsequent hair-cell depolarization, might be a source of sensorineural hearing loss and tinnitus associated with acoustic trauma.