Question

Why do bones show up white during the x-ray?

Answer 1

Hint: X-rays are a type of electromagnetic wave. When they are allowed to pass through the body, they form characteristic images. These images are used for various diagnostic purposes.

Complete answer:
X-rays are electromagnetic waves with a shorter wavelength. Thus, they have a more penetrating power. When x-rays are taken, it shows parts of our body in shades of black and white. The X-ray films are used for imaging bones and tissues that help in diagnostic purposes.

Radiodensity or radiopacity is the relative inability of those kinds of electromagnetic radiation to pass through a particular material. Various tissues can show different radiopacities and thus can be differentiated. Radiopacity depends on the atomic number of the material with which the object is made up of.

Bone is primarily made of Calcium and Phosphorous. Calcium in bones absorbs x-rays the most. Thus they appear white on the x-ray film. Depending on the mineral content of the bone there may be a normal variation. This variation helps to distinguish between compact and spongy bones. Soft-tissues and fat absorb less and look grey. Air having the least atomic numbers absorbs the least and thus appears black in the film. The last radiographic opacity that is visible on a radiograph is metal which is the opaque. This helps to identify dental implants and foreign metallic bodies.

Note: Radiography plays an important role in determining the type and extent of the fracture, to visualize soft tissue organs of the body like the uterus, gastrointestinal tract, etc., and to perform various catheter angiography procedures, stereotactic breast biopsies as well as intra-articular steroid injections.