Stridor is defined as which of the following?

• A. Harsh or high-pitched respiratory sound, caused by an obstruction of the air passages
• B. A low-pitched wheeze heard with asthma
• C. Grating sound made when the pleura rub together during respiration
• D. Inflammation of the protective membranes surrounding the brain and spinal cord caused by bacteria

Answer: (A)

Stridor signals an upper airway obstruction, shown by a harsh, high-pitched breath sound that is usually heard during inspiration. This specific sound arises when the airway above the thoracic trachea narrows or is blocked, such as from swelling, a foreign body, or infection affecting the larynx or trachea. That’s why this description best defines stridor.

The other sounds point to different problems: a low-pitched wheeze is typical of lower airway obstruction, like in asthma; a grating sound from the pleura rubbing together is a pleural rub; and inflammation of the brain and spinal cord coverings describes meningitis. Stridor’s association with upper airway obstruction is what makes it the correct choice.