Pulmonary interstitial emphysema is characterized by air in which location?

• A. Neck tissues
• B. Air within the acinus portions of the lung
• C. Air released into the tissues surrounding the bronchi
• D. Air within the alveolar spaces

Answer: (C)

In pulmonary interstitial emphysema, air collects in the lung’s interstitial tissues, specifically around the bronchi and pulmonary vessels. This air leaks from ruptured alveolar walls under high pressure and then tracks along the peribronchovascular interstitium, often toward the hila or mediastinum. That makes the interstitial space surrounding the bronchi the characteristic location. The alveolar spaces themselves (air within the acini or alveoli) are not the primary site for PIE, and while air can later extend to subcutaneous tissues such as the neck, the defining feature is interstitial air around the bronchi.