X-rays are the oldest and most commonly used type of medical imaging. Your doctor may order x-rays (radiographs), which are essentially pictures of your bones and joints. X-rays don't show cartilage, muscles, or ligaments. X-rays use electromagnetic radiation and are considered a very safe form of medical imaging. An x-ray machine is used to focus an x-ray beam on a specific part of the body to capture the images on x-ray film or record the images digitally.

Reading X-Rays

Bone and metal show up white on an x-ray because they are dense and block the x-ray beam, decreasing exposure of the film to the x-ray beam. Shades of gray on the x-ray represent soft tissue of various sizes and densities. Air appears black on x-ray.

Your doctor will be looking for evidence of joint damage or bone abnormalities on the x-ray images. It's possible to have evidence of abnormalities that are associated with aging, irrespective of pain or other symptoms. It's also possible to have normal x-rays even though you have inflammation, which is symptomatic.

A person is generally exposed to about 20 milliroentgens of radiation during a single x-ray exposure. The amount of radiation will be based on the body part to be x-rayed (e.g., a pelvic x-ray has much more radiation than a chest x-ray). To put it in perspective, each year every person is exposed to about 100 milliroentgens of radiation from sources like the sun and soil.