In foreign body aspiration, where does the object most commonly lodge?

• A. Right main stem bronchus
• B. Left main stem bronchus
• C. Trachea
• D. Esophagus

Answer: (A)

The main idea is that inhaled foreign bodies tend to follow the path of least resistance into the airway that lines up most directly with the trachea. The right mainstem bronchus is the most direct continuation of the trachea: it is shorter, wider, and more vertical than the left, so objects that are aspirated are more likely to enter it than the left bronchus.

The trachea carries the object into the bronchi, but the trachea itself is not the typical lodging site unless the object is large and causes obstruction there. The left mainstem bronchus is more angled and narrower, making it less likely to receive the aspirated object. The esophagus lies behind the trachea and is not part of the airway, so lodging there would not represent aspiration into the lungs.