Most common cause of congenital stridor?
**Core Concept**
Laryngomalacia is a congenital condition characterized by the softening of the tissues of the larynx, leading to partial airway obstruction. This results in inspiratory stridor, which is a high-pitched sound heard during inhalation.
**Why the Correct Answer is Right**
The most common cause of congenital stridor is laryngomalacia, which is due to the flaccid collapse of the supraglottic structures, particularly the aryepiglottic folds and the epiglottis. This collapse occurs during inspiration, causing a narrowing of the airway and resulting in the characteristic stridor. The exact mechanism is thought to be related to the incomplete development of the cartilaginous framework of the larynx.
**Why Each Wrong Option is Incorrect**
**Option A:** Laryngomalacia is more common than vocal cord paralysis, which can also cause stridor but is less frequent in the congenital setting.
**Option B:** Tracheomalacia is another cause of stridor, but it is less common than laryngomalacia and typically presents with expiratory stridor.
**Option C:** Subglottic stenosis is a congenital condition that can cause stridor, but it is less common than laryngomalacia and typically presents with a more severe airway obstruction.
**Clinical Pearl / High-Yield Fact**
Laryngomalacia is often associated with other congenital anomalies, such as cardiac defects and esophageal atresia, and is a common cause of respiratory distress in the neonatal period.
**Correct Answer: A. Laryngomalacia.**