What is stridor?

• A. Harsh crowing adventitious breath sounds caused by obstruction.
• B. Snoring-like adventitious breath sounds due to mucus.
• C. High-pitched whistling.
• D. Adventitious breath sounds caused by pleural spaces rubbing together.

Answer: (A)

Stridor is an audible, harsh crowing sound that results from turbulent airflow through a narrowed upper airway, such as the larynx or trachea. This quality—harsh and crowing—reflects upper airway obstruction and is often heard best on inspiration, signaling a potentially urgent airway issue. By contrast, a high-pitched whistling sound is more typical of wheezing from lower airway narrowing, snoring-like sounds suggest mucus plugging or secretions, and a pleural friction rub arises from the pleural surfaces rubbing together. This combination of features makes the harsh crowing sound due to obstruction the best description of stridor.