<unk>  is the most common cause of stridor in infancy. It occurs when the soft, immature cartilage of the upper larynx collapses inward during inhalation, causing airway obstruction.  It can also be seen in older patients, especially those with neuromuscular conditions resulting in weakness of the muscles of the throat.  However, the infantile form is much more common.
Laryngomalacia
Tracheomalacia
Epiglottitis
Vocal cord paresis
Meatal stenosis
Adenoiditis
Tracheal deviation
Cleft lip and palate