The test itself is completely painless. Some mild discomfort may result from lying on the table, a hard surface that may feel cool. Sometimes, to get a clear image of the injury, you may be asked to hold an uncomfortable position for a moment while the x-ray is taken. Any movement could blur the image and make it necessary to repeat the procedure to obtain a useful, clear picture. 

An x-ray examination involves exposing a part of the body to a small dose of radiation to produce an image of the internal structures. When x-rays penetrate the body, they are absorbed by the varying amounts densities within tissues. Ribs, for example, are dense and will block much of the radiation and, therefore, appear white or light gray on the image. Soft tissue such as the liver or lungs will appear darker because more radiation can pass through them to expose the film. The images may be transferred to film.   After a few months or even years, these images may be used to compare with more recent radiographs if needed.