Quadrangular Membrane in a Lateral Cross Section of the Larynx

Description

Seen in lateral cross section, the quadrangular membrane spans from the lateral margin of the epiglottis to the anterolateral surface of the arytenoid cartilage, forming a fibroelastic sheet in the supraglottic larynx. Its superior free edge thickens to create the aryepiglottic fold, which arcs posteriorly and inferiorly from the epiglottis toward the arytenoid apex, while its inferior free edge forms the vestibular ligament within the vestibular (false vocal) fold. Anteriorly, the membrane sits deep to the thyroid cartilage, with the hyoid bone positioned superior to the thyroid lamina and the cricoid cartilage inferior to it. Orientation is clear. This lateral section clarifies a teaching point that is often muddied in endoscopic views: the aryepiglottic fold is not just mucosa, it is structured by the quadrangular membrane and its embedded ligaments, which define the lateral boundary of the laryngeal inlet and the vestibule above the true vocal folds. Clinically, that anatomy frames supraglottic airway obstruction and guides supraglottoplasty, where incisions along the aryepiglottic fold must respect the underlying fibroelastic support to avoid destabilizing the vestibular fold and altering laryngeal competence during swallowing. Use this artwork in head and neck anatomy courses, otolaryngology teaching files, and surgical atlases covering supraglottic landmarks, the laryngeal inlet, and the relationship of the thyroid and cricoid cartilages to the vestibular space in a male larynx. It also suits publications discussing flexible laryngoscopy correlates of supraglottic edema, laryngomalacia, or supraglottic tumor spread patterns along the paraglottic and vestibular regions. Anatomical accuracy verified by SciePro's Medical Advisory Board.