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How are X-rays used to detect broken bones?

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Diagram of the electromagnetic spectrum showing different types of waves arranged by wavelength and frequency, from gamma rays and X-rays to ultraviolet, visible light, infrared, microwave, TV/FM radio, shortwave radio, AM radio, and longwave radio. — X-ray The relationship of X-rays to other electromagnetic radiation within the electromagnetic spectrum.

X-rays are used to detect broken bones by exploiting the principle of differential absorption. When a beam of X-ray radiation is directed through the body, different internal structures absorb the X-ray photons at varying rates based on their density and composition.12

Because bones contain calcium phosphate, they are denser than surrounding soft tissues and absorb more X-ray photons. Consequently, bones cast the sharpest shadows on the resulting X-ray image, allowing physicians to clearly distinguish the skeletal structure from muscles and organs. A fracture appears as a disruption or break in the continuity of these shadows, making it possible to identify bone injuries without the need for invasive procedures. For more complex cases, computed tomography (CT) may be used to provide detailed, high-resolution cross-sectional images that are more sensitive to small density variations than conventional X-ray techniques.231