Three-dimensional analysis of murine laryngeal development.

This study defines the critical stages in the prenatal development of the mouse larynx. Three-dimensional computer-generated solid model reconstructions display the changing anatomic relationships during laryngeal development from the earliest respiratory primordium to the mature laryngeal vestibule. These reconstructions demonstrate that the laryngeal vestibule forms as a result of a cephalocaudal separation of the epithelial lamina, thereby establishing communication between the laryngeal cecum and the pharyngoglottic duct. These results support the hypothesis that the cause of congenital supraglottic and glottic malformations is an incomplete separation of this epithelial lamina. The infraglottic lumen remains patent during laryngeal development. Continued lengthening of the foregut between the infraglottis and the carina forms the trachea. This is contrary to the 19th-century concept of an ascending tracheoesophageal septum. Formation of the laryngeal cartilages, muscles, and innervation is portrayed by the reconstructions; with minor variations, they correlate closely with earlier wax reconstructions of human laryngeal development. Future research with this animal model can provide additional insights into the complex mechanisms involved in congenital malformations of the larynx.