Skip to Content
Home > Patients & Visitors > Health Library > Nerve Function Tests for Evaluating Low Back Problems
The nerves that carry messages to and from your legs come from your
low back. By checking your muscle strength, your reflexes, and your
sensation (feeling), your doctor can tell whether there is pressure on a
nerve root coming from your spinal column. He or she
can often also tell which nerve root is involved.
Muscle strength tests can detect true muscle weakness, which is one
sign of pressure on a nerve root. (Sometimes leg weakness is actually due to
pain, not pressure on a nerve.) Most people who have
herniated discs that cause symptoms also have some
nerve root compression. Nerve root compression
usually originates in the lumbosacral region.
Specific muscles receive impulses from specific nerves, so finding
out which muscles are weak shows your doctor where nerve roots are being
Muscle strength tests include:
Just as your muscles receive signals through certain nerves, other
nerves carry signals back to your spinal cord from specific sections of your
skin and other tissues. Testing your sense of feeling helps your doctor find
out what nerve root may be compressed.
Your sense of feeling may be tested in several ways. Your doctor will
probably ask you to close your eyes during this testing, because it's easy to
imagine the feeling if you can see the test being done. Testing may include
touching your skin lightly with a cotton ball or pricking your skin lightly
with a pin.
Tendons attach the muscles to the bones. Reflexes are little movements of the muscle when the tendon is tapped. A reflex can be decreased or absent if there is a problem with the nerve supply. To test your reflexes, your doctor will use a rubber hammer to tap firmly on the tendon. If
certain reflexes are decreased or absent, it will show what nerve might be
compressed. Not all nerve roots have a reflex associated with
ByHealthwise StaffPrimary Medical ReviewerWilliam H. Blahd, Jr., MD, FACEP - Emergency MedicineSpecialist Medical ReviewerRobert B. Keller, MD - Orthopedics
Current as ofSeptember 30, 2014
Current as of:
September 30, 2014
William H. Blahd, Jr., MD, FACEP - Emergency Medicine & Robert B. Keller, MD - Orthopedics
How this information was developed to help you make better health decisions.
To learn more, visit Healthwise.org
© 1995-2015 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Feeling under the weather?
Use our interactive symptom checker to evaluate your symptoms and determine appropriate action or treatment.
Our interactive Decision Points guide you through making key health decisions by combining medical information with your personal information.
You'll find Decision Points to help you answer questions about:
Get started learning more about your health!
Our Interactive Tools can help you make smart decisions for a healthier life. You'll find personal calculators and tools for health and fitness, lifestyle checkups, and pregnancy.
Send Us Your Feedback
North Kansas City Hospital.