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. X-rays make a picture by striking a detector that either exposes a film or sends the picture to a computer. 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 only through air, such as through the lungs, look black on the picture.
Spinal X-rays are pictures of the spine. They may be taken to find injuries or diseases that affect the discs or joints in your spine. These problems may include spinal fractures, infections, dislocations, tumors, bone spurs, or disc disease.
Spinal X-rays are also done to check the curve of your spine (scoliosis) or for spinal defects.
The spine is divided into four parts. So there are four common types of spinal X-rays:
- Cervical spine X-ray. This X-ray test takes pictures of the 7 neck (cervical) bones.
- Thoracic spine X-ray. This X-ray test takes pictures of the 12 chest (thoracic) bones.
- Lumbosacral spine X-ray. This X-ray test takes pictures of the 5 bones of the lower back (lumbar vertebrae) and a view of the 5 fused bones at the bottom of the spine (sacrum).
- Sacrum/coccyx X-ray. This X-ray test takes a detailed view of the 5 fused bones at the bottom of the spine (sacrum) and the 4 small bones of the tailbone (coccyx).
The most common spinal X-rays are of the cervical vertebrae (C-spine films) and lumbosacral vertebrae (LS-spine films).
Why It Is Done
A spinal X-ray is done to:
- Find the cause of ongoing pain, numbness, or weakness.
- Check for arthritis of the joints between the vertebrae and the breakdown (degeneration) of the discs between the spinal bones.
- Check injuries to the spine, such as fractures or dislocations.
- Check the spine for effects from other problems, such as infections, tumors, or bone spurs.
- Check for abnormal curves of the spine, such as scoliosis, in children or young adults.
- Check the spine for problems present at birth (congenital conditions), such as spina bifida, in infants, children, or young adults.
- Check changes in the spine after spinal surgery.
How To Prepare
Before the X-ray test, tell your doctor if you are or might be pregnant. The risk of radiation exposure to your unborn baby (fetus) must be considered. The risk of damage from the X-rays is usually very low compared with the potential benefits of the test. If a spinal X-ray is absolutely necessary, a lead apron will be placed over your belly to shield your baby from the X-rays.
You may need to take off any jewelry that may be in the way of the X-ray picture, such as if you have a pierced belly button.
You don't need to do anything else before you have this test.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form( What is a PDF document? ).
How It Is Done
A spinal X-ray is taken by a radiology technologist. The X-ray pictures are usually read by a doctor who specializes in reading X-rays (radiologist).
You will need to remove any jewelry that may be in the way of the X-ray picture. You may need to take off some of your clothes, depending on which area is examined. You will be given a cloth or paper gown to use during the test. You may be allowed to keep on your underwear if it does not get in the way of the test.
During the X-ray test, you will lie on an X-ray table. If the X-ray is being taken because of a possibly serious injury to your neck or back, to prevent causing more injury a radiologist will look at the first X-ray pictures before taking others. If you have a neck brace (cervical collar) in place, X-ray pictures may be taken and a physical exam done to see whether the brace can be taken off without hurting the spine.
Usually 3 to 5 X-ray pictures are taken. You need to lie very still to avoid blurring the pictures.
A spinal X-ray usually takes about 15 minutes. You will wait about 5 minutes until the X-rays are processed in case more pictures need to be taken. In some clinics and hospitals, X-ray pictures can be shown right away on a computer screen.
How It Feels
You will feel no discomfort from the X-rays. The X-ray table may feel hard, and the room may be cool. You may find that the positions you need to hold are uncomfortable or painful, especially if you have an injury.
There is always a slight risk of damage to cells or tissue from being exposed to any radiation, including the low levels of radiation used for this test. But the risk of damage from the X-rays is usually very low compared with the potential benefits of the test.
For example, the radiation exposure from a chest X-ray is about equal to the natural radiation exposure received during a round-trip airline flight from Boston to Los Angeles (or Montreal to Vancouver) or 10 days in the Rocky Mountains (Denver, Colorado).
In an emergency, a doctor can see the results of a spinal X-ray in a few minutes. Otherwise, a radiologist usually has the official X-ray report ready the next day.
The bones of the spine (vertebrae) are normal in number, size, shape, appearance, and how they are lined up.
No broken bones, dislocations, or foreign objects are present. The soft tissues around the vertebrae look normal.
The spine is not abnormally curved.
Broken bones, dislocations, or foreign objects are present.
The spine is abnormally curved, such as from scoliosis.
Diseases that affect the spine, such as thin bones (osteoporosis) or arthritis, are present. One or more bones in the spine may be abnormal because of a condition you were born with or because of cancer, infection, or trauma.
Disc disease, which is fairly common, can sometimes be seen on a spinal X-ray as a narrowed space between the bones of the spine. Bone spurs can also be seen.
What Affects the Test
Reasons you may not be able to have the test or why the results may not be helpful include:
- If you are pregnant. The X-rays may not be safe for the fetus.
- If you can't remain still during the test. The pictures may not be clear.
- If you are very overweight. This can make it hard to see the details of the spinal X-ray.
What To Think About
- Your X-ray results may be different from earlier test results because you were tested at a different medical center or you had a different kind of test.
- The most common causes of low back pain, such as strained back muscles or ligaments, do not show up on a spinal X-ray.
- Other tests, such as a CT scan, an MRI, or a myelogram, provide more information about the spinal bones, joints, nerves, discs, muscles, and ligaments than a spinal X-ray.
- Spinal X-rays have been used by some employers to screen healthy people for possible future back problems. But most doctors do not believe that this is appropriate. If a potential employer wants you to have a spinal X-ray before you can start working, you may want first to discuss the matter with the employer and your doctor.