Are rare anomalies in neonates. Between weeks 4 and 8 of intrauterine life, the laryngotracheal groove in the chest develops into the larynx, trachea, and beginning lung tissue; the esophageal lumen forms parallel to this. A number of anomalies can occur of the trachea and esophagus are affected by a teratogen that does not allow the two organs to fully form separately.