During the physical exam, your doctor will check your back for tenderness. He or she may ask you to lie flat and move your legs into various positions to help determine the cause of your pain. Your doctor may also perform a neurological exam, to check your:
- Muscle strength
- Walking ability
- Ability to feel light touches, pinpricks or vibration
In most cases of herniated disk, a physical exam and a medical history are all that's needed to make a diagnosis. If your doctor suspects another condition or needs to see which nerves are affected, he or she may order one or more of the following tests.
- X-rays. Plain X-rays don't detect herniated disks, but they may be performed to rule out other causes of back pain, such as an infection, tumor, spinal alignment issues or a broken bone.
- Computerized tomography (CT scan). A CT scanner takes a series of X-rays from many different directions and then combines them to create cross-sectional images of your spinal column and the structures around it.
- Magnetic resonance imaging (MRI). Radio waves and a strong magnetic field are used to create images of your body's internal structures. This test can be used to confirm the location of the herniated disk and to see which nerves are affected.
- Myelogram. A dye is injected into the spinal fluid, and then X-rays are taken. This test can show pressure on your spinal cord or nerves due to multiple herniated disks or other conditions.
Electromyograms and nerve conduction studies measure how well electrical impulses are moving along nerve tissue. This can help pinpoint the location of the nerve damage.