Laryngeal and tracheal anomalies are a diverse collection of congenital and acquired anomalies that primarily affect neonates and young children. Characteristic symptoms are airway obstruction, recurrent respiratory infections, feeding difficulties, and failure to thrive. Unfortunately, we do not yet understand how these anomalies develop and why certain children are affected. The first part of the thesis focuses on understanding the development of the normal and anomalous trachea. A more detailed examination of tracheal cartilage development in human embryos has prompted the proposal of a new theory on the etiology of complete tracheal ring deformity (CTRD). Furthermore, morphometric analysis of the trachea in fetuses has shown similar dimensions between Down syndrome and non-Down controls. This finding makes the necessity of a smaller size endotracheal tube in Down syndrome neonates debatable. The second part of the thesis focuses on treatment considerations. Improvement of current treatment techniques have been described for a third or fourth branchial pouch sinus causing airway obstruction and for severe tracheobronchomalacia necessitating aortopexy surgery. Furthermore, a structured overview of tracheal anomalies associated with Down syndrome has offered clinicians valuable insights into this relatively unknown topic
