Quadrangular Membrane, Superior View

Description

Positioned at the superior aspect of the laryngeal inlet, the quadrangular membrane spans between the lateral margins of the epiglottis anteriorly and the arytenoid cartilages posteriorly, forming a broad fibroelastic sheet in the supraglottic larynx. Its inferior free edge thickens into the vestibular ligament (false vocal fold), which lies superior to and more lateral than the true vocal fold and vocal ligament. Medially, the membrane contributes to the aryepiglottic fold, running from the epiglottis toward the arytenoid region, while laterally it blends with the inner surface of the thyroid cartilage. Orientation from a superior viewpoint clarifies how this membrane frames the entrance into the laryngeal vestibule. Clinically, this anatomy matters because supraglottic edema, infection, or tumor spread often tracks along these fibroelastic planes, distorting the aryepiglottic folds and narrowing the laryngeal inlet before the glottis is directly involved. The vestibular folds created by the quadrangular membrane are also a frequent source of dysphonia in muscle tension dysphonia and can be deliberately recruited in ventricular phonation. Surgeons rely on these landmarks during transoral supraglottic laryngectomy and endoscopic evaluation, where recognizing the relationship of the quadrangular membrane to the epiglottis and arytenoids helps maintain the airway while preserving swallowing function. A small structure, big consequences. Use this illustration in head and neck anatomy teaching (larynx and pharynx modules), otolaryngology texts covering supraglottic anatomy, and operative manuals illustrating endoscopic approaches to the laryngeal vestibule and vestibular folds. It also supports speech-language pathology materials on false vocal fold phonation and supraglottic hyperfunction. Anatomical accuracy verified by SciePro's Medical Advisory Board.