What is an abdominal x-ray?

An abdominal X-ray is a picture of structures and organs in the belly (abdomen). This includes the stomach, liver, spleen, large and small intestines and the diaphragm, which is the muscle that separates the chest and belly areas. Often two X-rays will be taken from different positions. If the test is being done to look for certain problems of the kidneys or bladder, it is often called a KUB (for kidneys, ureters and bladder).

X-rays are a form of radiation, like light or radio waves, that are focused into a beam, much like a flashlight beam. X-rays can pass through most objects including the human body. When X-rays strike a piece of photographic film, they make a picture. Dense tissues in the body, such as bones, block (absorb) many of the X-rays and look white on an X-ray picture. Less dense tissues, such as muscles and organs, block fewer of the X-rays (more of the X-rays pass through) and look like shades of gray on an X-ray. X-rays that pass mostly through air, such as through the lungs, look black on the picture.

An abdominal X-ray may be one of the first tests done to find a cause of belly pain, swelling, nausea or vomiting. And other tests (such as ultrasound, CT scan, or intravenous pyelography) may be used to look for more specific problems.