Stridor is the audible symptom produced by the rapid, turbulent flow of air through a narrowed segment of the respiratory tract, more specifically, the large airways. It is often the most prominent symptom of airway obstruction in the pediatric patient. Proper management is possible only after a precise diagnosis has been established. Stridor is a symptom and not a diagnosis. It cannot be managed appropriately on the basis of a presumptive or inferential diagnosis.
Stridor is most often inspiratory.
It typically originates from the larynx, upper trachea, or hypopharynx. The term stertor has been used to describe the low-pitched inspiratory snoring sound typically produced by nasal or nasopharyngeal obstruction. This sound is similar to, and frequently mistaken for, other intrathoracic conditions such as bronchomalacia, tracheomalacia, or foreign bodies in the trachea or bronchi. Obstructive lesions of the airways produce turbulent air flow. The pathophysiology of this phenomenon is explained by Bernoulli's principle.