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How This Simple Leg Test Helps Doctors Diagnose Herniated Discs

Published April 18, 2017    

Are you in constant pain? Do you feel a tingling sensation moving up and down your leg? Are you sick of radiating pain all of the time? This may be due to a disc herniation — a common problem amongst patients with lower back pain. A method many health care professionals use to test for this disc disorder is a combination of medical history paired with signs of a reduced range of motion and the straight leg raise test (SLR).

Physicians refer SLR testing as a neurodynamic exam, assessing your reaction to man-made pressure and how your neurological tissue reacts to that pressure. SLR is essential in order for your doctor to properly diagnosis the potential disc herniation.

During the exam, the assessor will begin by having you lay flat on the testing table without any additional support. You will then be asked to extend your knee passively.  Most physicians completing this test will begin with the unaffected leg first. Doing so, allows both parties to ease into the movements without worrying too much about the initial pain levels. The non-testing leg will remain in the resting position. You will feel a riveting force on the affected nerve root as the assessor attempts to replicate your symptoms.

The physician will pinpoint the exact angle where those symptoms begin. A positive test occurs when the reproduction of symptoms emerges at an angle of hip flection that is less than 40 degrees. Depending on the angle of the pain, you may or may not have a disc herniation. If you are able to bend at an angle greater than 70 degrees, the pain usually stems from the lumbar spine. Bending at an angle of 35 degrees to approximately 70 degrees, the tension would be coming from the sciatic roots over your intervertebral discs.

The testing continues until the pain becomes unbearable. The assessor then slowly brings your leg down to the resting position ensuring you are no longer in pain. While at that point, you are asked to actively flex your neck — a technique referred to as “Neri’s Sign” — or bring your chin to your chest; both can be done at the same time or right after another. If the pain is also reflected throughout the final two exams, you are most likely suffering from a lesion within the spinal cord caused by a disc herniation.

Dean Moyer, author of Rebuild your Back reported, “I’ve got scientific proof straight from the big boys themselves that herniated discs — if treated properly — will not only heal on their own but will shrink back up and totally disappear about 90 percent of the time.”

Doctor Ian McNab supported Moyer’s remarks, “Sequential MRI scans done at six-month intervals have shown that disc herniation’s more often than not are resorbed by the body. The studies found that larger disc herniations do not correlate with a poor prognosis. They go away. 90 percent of patients will get better and stay better with conservative care.”

Fortunately, disc herniations sometimes fade away either on their own or with proper physical exercise approved by your medical team making this an important test to consider. If you are feeling extreme pain along with an uncomfortable burning sensation, it may be worth checking out. Schedule an appointment with your medical professional to see if performing the straight leg raise test can assist in diagnosing and treating your chronic back pain. You don't have to continue wondering what your symptoms mean.

Last change: January 27, 2019