The vestibular ligament (ventricular ligament) is the lower free edge of the quadrangular membrane, running from the arytenoid cartilage posteriorly to the thyroid cartilage anteriorly within the vestibular fold (false vocal cord). It lies superior and lateral to the vocal ligament and the laryngeal ventricle separates it from the true vocal cord below. It is composed of fibrous tissue without the elastic properties of the vocal ligament.
Provides the fibrous core of the vestibular fold (false cord), which acts as a secondary airway protector during forceful airway closure and Valsalva manoeuvre; the paired vestibular folds may adduct to assist the true cords in complete laryngeal closure during swallowing and increased intra-abdominal pressure tasks.
The vestibular fold and its ligamentous core are used as alternative vibrating structures in 'ventricular dysphonia' (false cord phonation) where the false cords adduct to produce a low-pitched rough voice when the true cords cannot vibrate (due to paralysis, scar, or tumour). Ventricular dysphonia produces a characteristic excessively low-pitched voice from the mass of the false cord vibrating. Paradoxical vocal fold motion disorder may involve false cord activity. In transoral laser supraglottectomy, the vestibular folds are resected with their ligamentous core as part of the supraglottic larynx specimen.
Loss of true vocal cord function from paralysis or significant scarring can lead to compensatory false cord phonation where the vestibular folds and their ligamentous cores adduct and vibrate to produce a low rough voice; voice therapy addressing the compensation pattern and treating the underlying cord dysfunction where possible is the management approach.
