Which percussion note suggests pneumothorax?

• A. Dullness
• B. Tympany
• C. Flatness
• D. Hyperresonance

Answer: (D)

Percussion tones reflect the air–tissue content beneath the chest wall. In a pneumothorax, air collects in the pleural space, increasing overall air content and reducing the density of the underlying lung. That excess air makes the chest sound more resonant when tapped—a hyperresonant, louder, and sometimes longer tone. This contrasts with dullness, which points to fluid or solid tissue like pneumonia or pleural effusion; flatness, which indicates very dense tissue such as bone or a large mass; and tympany, which suggests gas-filled hollow organs (like bowel) and is not typical of the chest in a pneumothorax. So the hyperresonant percussion finding best signals a pneumothorax.