Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4586_Библиотеки_им_академика_М_И_Перельмана

The shape can be classied into: (1) omega-shaped (sharply curved if the angle between its lateral parts was less than 90° at the central portion) epiglottis; (2) normally curved epiglottis shape; and (3) at epiglottis. An epiglottis was classied as at if its medial part lacked the characteristic anterior convexity [25]. In most cases of obstruction at epiglottis and/or tongue base, the epiglottis was at (type 3), where it was lacking the typical anterior convexity in its upper part. The hypothesis was that the change of its shape is a result of degeneration of the suspensory apparatus that maintains the convexity of the epiglottis and maintains it in position. This may help identify patients with narrowing at this level [25]. Another nding was that subjects with isolated epiglottic collapse have lower mandibular plane to hyoid distance and tend to have a bigger angle of their epiglotic curvature [26]. For full details on anatomy, please review Chap. 5. Epiglottic collapse can vary based on the phenotype from a oppy epiglottis (primary) to a retro-displaced epiglottis by the tongue base (secondary) and from partial to complete collapse. The epiglottis can also collapse into two different patterns: one where it is retro-displaced in an antero- posterior (AP) direction, thereby obstructing the laryngeal inlet. This is also known as the trapdoor phe­nomenon. Alternatively, it can collapse in a lateral direction (omega-shaped pat­tern), thereby resulting in obstructing at the level of the hypopharynx or laryngeal inlet [17–19].