What kind of sound would you expect when performing percussion over fluid-filled organs?

When performing percussion over fluid-filled organs, the sound produced is typically flat. This is due to the density and composition of the fluid, which does not allow sound waves to resonate and reverberate as they would in organs filled with air, such as the lungs. In a flat sound, the vibrations are dampened, resulting in a shorter duration and less resonance, characteristic of solid or fluid-filled structures.

A resonant sound would be produced when percussing over air-filled spaces, where the sound can bounce and create a fuller tone. Hollow sounds are typically associated with larger air-filled areas, such as the lungs, and a drum-like sound may be used to describe a specific technique or certain conditions but does not apply to fluid-filled organs. Therefore, the flat sound is the correct response, as it accurately represents the dullness of percussion over a fluid medium.