acoustic shadow

An acoustic shadow occurs when a solid object or dense material blocks sound waves, preventing them from reaching the area behind it. This creates a region of decreased or no sound signal, similar to a shadow cast by an object blocking light. In medical ultrasound, for example, bones or stones can cause acoustic shadows, making it difficult to see structures behind them. It is a natural consequence of how sound waves interact with different materials, resulting in a darker or less clear area on the imaging display.