How do they test for sciatica?



Sciatica is a general medical term that describes a set of symptoms. The symptoms include low back pain and radiating pain into the leg and foot along the course of the sciatic nerve. This pain may be sharp with tingling and numbness often associated with it.

Sciatica Diagnosis

However, prior to any tests, a thorough history and physical exam is in order. Some of the things that physicians look for include the timing of the pain, location of the pain, severity, associated symptoms, and what makes the pain better or worse.

Some of these physical exams and questions help the physician determine if the pain is likely coming from a spinal problem such as a herniated disc or spinal stenosis. Other tests can point toward muscular issues such as piriformis syndrome or a muscle strain. Still other history and physical findings can alert doctors to more ominous causes of sciatica such as tumors along the nerve or in the spine.


“X-rays” is a common name for radiographic images produced by passing x-ray radiation through body tissues on to film or a digital sensor that converts the pattern into an image. The reason that the image is formed is because different tissues in the body absorb or blocked the x-ray radiation to different degrees. For instance, bone blocks more x-rays than fat or muscle. This causes the bone to show up as white on the film or image and softer tissues to show up darker. In the soft tissues, more of the x-rays get through to the film or sensor plate.


MRI of Low Back For Sciatica

MRI technology works by using a very strong magnet which affects the polarity of cells in the body. The MRI machine that measures the degree and speed at which the magnetic fields in the body returned to normal. It converts this information into an image which is much more refined and specific in regards to soft tissues such as nerves, discs, and blood vessels. It is also useful in detecting subtle changes in bone such as edema which can occur with a fracture.

CT Scans:

CT Scan for Sciatica

CT scans (Computerized Tomography) use x-ray beams but give images somewhat similar to MRIs. Although CT scans are usually not as clear as MRI in regards to soft tissue, they can have some advantages in diagnosing problems with bones. Additionally, if an MRI cannot be used due to implanted metallic hardware such as a spinal cord stimulator, shrapnel, aneurysm clips, or other similar metallic structures in the body; CT scans can often give adequate imaging to help the doctor make a clinical decision. Although util recently, individuals with spinal cord stimulators could not have MRI studies, some of the new spinal cord stimulator models are MRI copatible. CT scans can also be used in conjunction with contrast dye to help diagnose problems with blood vessels or evaluate the degree of compression on nerve structures as in a CT myelogram. CT scans can also be combined with other studies such as nuclear bone scans to give very precise images with 3-D reconstruction.

EMG/Nerve Conduction Studies

EMG/Nerve Conduction

Electromyogram (EMG) and nerve conduction studies are used to determine if there is compression or damage along the route of a nerve. These studies can also be used to determine if the nerve itself is diseased. These sorts of studies can be useful in determining whether the electrical energy along the path of a nervous being interrupted by compression such as occurs with carpal tonal syndrome or a herniated disc. Diseases of the nerves such as diabetic neuropathy can be evaluated with this type of study. The severity of nerve damage can be determined with an EMG to see if motor nerves are adequately sending signals to the muscles that they innervate. This information can be helpful in determining both the prognosis as well as the appropriate treatment for a variety of musculoskeletal and neurological disorders.

Other Resources:

Sciatica Tests and diagnosis – Mayo Clinic
Effectiveness of Diagnostic Tools for Sciatica – Spine-Health
Exams and Tests for Sciatica: How Your Doctor Diagnoses Sciatic Nerve Pain: Spine Universe
5 Ways To Tell If You Have Sciatica | Prevention




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