The conus elasticus (cricovocal membrane) is the paired elastic fibrous membrane spanning from the superior border of the cricoid cartilage to the vocal ligament (free upper edge) on each side, forming the lateral wall of the subglottis. The upper free edge of the conus elasticus forms the vocal ligament — the anatomical core of the true vocal cord. The anterior midline portion is thickened as the median cricothyroid ligament (cricovocal membrane anterior part), palpated and incised in emergency cricothyrotomy.
Forms the elastic framework of the subglottic larynx connecting the cricoid to the vocal folds; its upper free edge (vocal ligament) provides the vibrating edge of the true vocal cord; the medial thickening (median cricothyroid ligament) is the surgical target for emergency airway access.
The conus elasticus and specifically its median portion (median cricothyroid ligament) is the target of emergency cricothyrotomy: the ligament is palpated in the midline below the thyroid cartilage notch and above the cricoid, incised horizontally, and dilated to accept a tube for emergency airway access. Subglottic carcinoma invades the conus elasticus as it extends from the subglottis inferiorly, determining resectability and the extent of laryngeal resection. Congenital subglottic stenosis involves congenital narrowing of the conus elasticus framework.
In cannot-intubate cannot-oxygenate emergency, the median cricothyroid ligament (thickened anterior conus elasticus) is rapidly identified by palpating the midline laryngeal landmarks, horizontally incised between the thyroid and cricoid cartilages, and dilated to allow tube placement; the conus elasticus provides the anatomical target for this life-saving procedure.
