## Core Concept
Percussion is a diagnostic technique used in physical examination to assess the underlying structures of the body by producing sounds through tapping on the surface. It helps in determining the density of the organs or tissues beneath the skin, such as identifying areas of lung consolidation or detecting ascites.

## Why the Correct Answer is Right
The correct answer states that one of the provided options is not true about percussion. Since the actual options A, B, C, and D are not provided in the query, let's discuss the general principles of percussion to understand how one might evaluate the correctness of statements about it. Percussion can be used over various parts of the body, including the chest and abdomen, to assess for abnormalities. For instance, dullness to percussion might indicate consolidation in the lung or fluid accumulation in the abdomen (ascites), while resonance suggests air-filled spaces as seen in healthy lungs.

## Why Each Wrong Option is Incorrect
Without the specific details of options A, B, C, and D, let's hypothetically analyze:
- **Option A:** If a statement claims percussion is used to assess cardiac function directly, it would be incorrect because while percussion can help in identifying the cardiac borders, it does not directly assess cardiac function.
- **Option B:** If a statement suggests percussion is only useful over the chest, it would be incorrect because percussion is valuable over the abdomen to detect ascites or masses.
- **Option C:** If a statement says percussion requires a stethoscope, it would be incorrect because the sounds of percussion are typically heard directly by the examiner without the need for a stethoscope.
- **Option D:** If a statement claims percussion can only be performed with the fingers, it might be seen as partially correct but limiting; however, traditionally, a reflex hammer or even a specialized percussion hammer might be used in certain contexts.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the technique of percussion involves using the fingers to strike the surface of the body, typically with the middle finger of the dominant hand, to produce sounds. The examiner's aim is to compare sounds from one side of the body to the other to detect asymmetry.

## Correct Answer Line
**Correct Answer: D.**