What does a detection of "fluctuance" in a physical exam usually imply?

The detection of "fluctuance" during a physical exam typically indicates the presence of an abscess. Fluctuance is characterized by a soft, boggy feel to a fluid-filled area, reflecting that there is a collection of fluid, most commonly pus, under the skin. This finding suggests that the underlying condition may be an accumulation of pus in a defined space, which is common in abscesses formed due to infection.

When examining a lesion or mass, if fluctuation is noted, it implies that the mass is not solid and is likely due to the presence of fluid that can move within the confines of the abscess. In contrast, air collections usually present quite differently and are not associated with the same tactile quality as fluctuant masses. Bone fractures or muscle strains don't typically produce fluctuation; instead, they present with tenderness, swelling, or decreased range of motion without fluid accumulation under the skin. Therefore, the presence of fluctuation during an examination is a reliable indicator of abscess formation.