In chest percussion, what does resonance refer to?

• A. Absence of sound
• B. Dullness
• C. Quality of deep, full, reverberating sound
• D. Hyperresonance

Answer: (C)

Resonance is the sound you get when tapping a normal, air-filled lung. It’s a deep, full, reverberating note that sounds hollow and carries well. This indicates that the underlying tissue is mostly air and there’s no large amount of fluid or solid material in that spot. If the percussion note is dull, the area is likely fluid-filled or solid (like pneumonia, edema, or a tumor). If the note is hyperresonant, there’s too much air (as in pneumothorax or emphysema). Absence of sound would be unusual and suggests something obstructing the sound path. So resonance specifically describes that deep, full, reverberating quality.