A lumbosacral spine X-ray is an imaging test that helps your doctor view the bones of your lower back. It uses small amounts of electromagnetic radiation to help healthcare professionals evaluate bone breaks, joint issues, and other conditions.

This type of X-ray may also be called a lumbar spine X-ray. It takes pictures of the lumbar spine, which is the lowest part of the spine that sits below the cervical (upper) and thoracic (middle) sections of the spine.

It can also take pictures of the sacrum, which is the bony “shield” at the back of your pelvis, below the lumbar spine. The coccyx, or tailbone, is located below the sacrum.

Your doctor could order a lumbar spine X-ray for a variety of reasons. It can be used to view an injury from a fall or accident. It can also be used to monitor the progression of a condition like osteoporosis or to determine if a treatment you’re having is working.

An X-ray is a useful test for many conditions. It can help your doctor understand the cause of chronic back pain or view the effects of injuries, disease, or infection.

Your doctor may order a lumbar spine X-ray to evaluate:

Your doctor might also use other imaging tests along with an X-ray to determine the cause of symptoms like back pain. These can include:

Each of these scans yields a different type of image.

X-rays are routine procedures that don’t require much preparation.

Before the X-ray, you’ll be asked to remove any jewelry and other metallic items from your body. Tell your doctor if you have any metal implants from prior surgeries.

Most likely, you’ll change into a hospital gown to prevent any buttons or zippers on your clothes from affecting the quality of the X-ray images.

X-rays are performed in a hospital’s radiology department or at a clinic that specializes in diagnostic procedures. Many lumbosacral X-rays are done while standing to evaluate how the load of your body affects your spine position.

In some cases, you may start by lying down on a table, facing up. A technician will move a large camera connected to a steel arm over your lower back. A film inside the table will capture the X-ray images of your spine as the camera moves overhead.

The technician may ask you to lie in several positions during the test — including on your back, side, stomach, or even sitting — depending on what views your doctor has requested.

While the images are taken, you’ll have to hold your breath and remain still. This ensures that the images are as clear as possible.

Lumbar spine X-rays typically don’t take very long, sometimes as little as 15 minutes. However, the time it takes can depend on many factors, including how many images are needed or how clear the images turn out.

After the test, you can change back into your regular clothes. Most people can resume their usual activities right away.

Your radiologist and doctor will review the X-rays and discuss their findings. Results from your X-ray may be available the same day, or it may take longer.

Your doctor will determine how to proceed depending on what the X-rays show. They may order additional imaging scans, blood tests, or other tests to help make an accurate diagnosis.

All X-rays involve exposure to a small amount of radiation. The National Cancer Institute notes that the cancer risk from X-rays and other procedures that use radiation is very small, with the benefits generally outweighing the risks.

However, some people may have a higher risk from radiation than others. For example, because a lumbosacral spine X-ray involves the abdomen and pelvis areas, someone who is pregnant may need to undergo a different imaging test that doesn’t use radiation to avoid harming their unborn baby.

Children are also more sensitive to radiation. Your care team may adjust the X-ray machine settings to be safer for children, or they may recommend a different kind of imaging test altogether.

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Lumbosacral spine X-rays can help healthcare professionals diagnose and evaluate many conditions, including fractures, bone weakening, and other conditions that may affect the lower spine and adjacent areas.

These imaging tests are usually short procedures. Ask your doctor about how to prepare for your test and when you can expect your results.