When percussing over the cardiac border, what sound does it change from?

When percussing over the cardiac border, the sound changes from resonance to dull. This is because the heart, being a solid organ, does not resonate like the air-filled structures of the lungs. When you percuss over an area containing lung tissue, the sound is typically resonant due to the air. However, as you move to the area where the heart is located, the solid structure produces a dull sound, indicating the presence of denser tissue rather than air. This transition is important for clinicians to recognize, as it helps in determining the boundaries of the heart and assessing for any potential abnormalities in heart size or condition. Understanding this change in sound illustrates the different densities and compositions of the underlying structures being assessed through percussion.