Development of respiratory system and congenital anomalies

• Respiratory system develops from the endodermal respiratory (laryngotracheal) diverticulum at 4 weeks IUL; splanchnic mesoderm forms its cartilage and muscle.

Formation of the Laryngotracheal Diverticulum

Sequence

• Laryngotracheal groove → laryngotracheal diverticulum → tracheoesophageal septum separates trachea from esophagus → diverticulum bifurcates into bronchial buds → buds invaginate pericardioperitoneal canals → canals form pleural cavities.