quadrangular membrane quadrangular membrane the quadrangular membrane is a layer of submucosa. it contains the cuneiform cartilages. the membrane runs between the lateral aspects of the epiglottis and arytenoid cartilages on each side. the free inferior border of the quadrangular membrane is the vestibular ligament which is the vestibular fold when covered by mucosa. the lower fibres of the quadrangular ligament condense to form the false vocal cords or the vestibular fold, while the upper fibres of the cricovocal ligaments condense to form the true vocal cord. the superior border is in the aryepiglottic fold. larynx: quadrangular membranethe quadrangular membrane runs from the aryepiglottic fold to the vestibular ligament.detailsidentifierslatinmembrana quadrangularista98a06.2.09.022ta21658fma55247anatomical terminology