Quadrangular membrane

Abstract: The aryepiglottic folds extend between the arytenoid cartilage and the lateral margin of the epiglottis on each side and constitute the lateral borders of the laryngeal inlet. They are involved in physiologic closure mechanisms of the larynx and in pathologic conditions such as inspiratory stridor. Information on the normal topography of the aryepiglottic folds is poor and controversial. Therefore, this region was reinvestigated in serial whole-organ sections of 25 plastinated normal adult human larynges. Dorsally, the right and the left aryepiglottic folds are separated by the interarytenoid notch and comprise the corniculate and cuneiform cartilages, as well as numerous groups of mucous glands. Ventrally, the aryepiglottic folds are adjacent to the peri-epiglottic adipose tissue. Both regions are clearly separated by several layers of transversely oriented collagenous fiber layers. The muscular constituent of the aryepiglottic folds is only poorly developed, and no muscle fibers insert at the epiglottis. A coherent quadrangular membrane representing a ligamentous "skeleton" of the aryepiglottic folds is absent. A conspicuous collagenous fiber layer is found only to strengthen the free dorsal margin of the fold. Both muscular and ligamentous components may render the aryepiglottic folds sufficiently tense as to resist inspiratory inward suction in normal cases. However, pliability must be preserved to guarantee adequate folding in approximation of the aryepiglottic folds during deglutition. Thereby, the posterior part of the laryngeal inlet is closed, whereas the anterior part is probably closed by independent inward bulging of the peri-epiglottic adipose tissue.

Abstract: Background. Anatomic barriers to the spread of laryngeal cancer include the conus elasticus, the quadrangular membrane, and the thyroid cartilage. It has been speculated that an elastic barrier surrounds and protects the ventricle. Methods. The authors studied the microanatomic patterns of spread of 17 cases of patients who had laryngeal cancer with paraglottic disease and confirmed their findings by examining normal autopsy specimens. Results. Five patients of the seventeen cases showed no ventricular mucosal involvement despite extensive paraglottic disease. Both an inner, central, subepithelial periventricular elastic barrier, and a more peripheral periventricular elastic membrane barrier were identified; the latter was in continuity with the conus elasticus and quadrangular membrane

Abstract: Objective The predictability of laryngeal cancer spread is due in part to connective tissue membranes. These membranes function as barriers to cancer and divide the larynx into subunits. The field of laryngeal conservation surgery is based on these concepts. The quadrangular membrane plays an important role, hindering the lateral spread of cancer in the larynx. The composition of this membrane has not been well described in the literature. In this study, we examine basic characteristics of the quadrangular membrane using histological techniques. Methods Whole organ sections of the larynx were used. These sections were examined under a microscope with stains specific for collagen and elastin. Results Examination of the sections revealed that the quadrangular membrane is made up of closely woven undulating collagen and elastic fibers. Conclusion The quadrangular membrane is a fibroelastic structure providing a barrier to cancer spread.

Abstract: Significant Anatomical Structures: quadrangular membrane, conus elasticus, cricoid cartilage, thyroid cartilage, arytenoid cartilage, Santorini’s corniculate tubercle, Wrisberg’s cuneiform tubercle, Reinke’s space, thyrohyoid membrane, thyroepiglottic ligament, preepiglottic space, paraglottic space, Broyle’s tendon, crista arquata, oblong fovea, subglottic region, arytenoid cartilage, anterior commissure