What does percussion in physical assessment primarily evaluate?

Percussion in physical assessment is primarily utilized to evaluate the densities within organs. When a healthcare provider performs percussion, they tap on the body surface to produce sound waves. The characteristics of these sounds can provide important information about the underlying structures. Different densities create different sounds; for instance, a normal lung filled with air will produce a resonant sound, whereas a solid organ like the liver will produce a dull sound. This practice helps clinicians discern between various conditions, such as fluid accumulation, masses, or organ enlargement, based on the changes in sound quality and resonance.

In the context of the other choices: measuring heart rate pertains to auscultation and palpation methods, while detecting friction rubs is also an auscultation technique that evaluates specific sounds associated with lung or heart conditions. Evaluating temperature variations is done through palpation or thermometric methods, which assess surface temperature, rather than assessing internal densities. Therefore, the primary purpose of percussion is indeed focused on evaluating the densities within organs.