Using the Lasègue Test for Diagnosing Sciatica

When you have had a consistent pain in your leg, buttock, or back for a few days or weeks, you most likely will head to your general practitioner to find out what is going on. They will likely ask you a few questions about how or when your pain began, and then perform a series of tests to establish the diagnosis of your pain. These tests can include magnetic resonance imagery (MRI), computerized tomography (CT scans) or magnetic resonance neurography (MRN), but sometimes the wait times for these types of scans can be lengthy, so an immediate test is usually done to determine whether your pain could be caused by sciatica.

General practitioners use a common diagnostic test called the Lasègue Test in cases of radiating leg or back pain to diagnose the likelihood of sciatica. This test involves having the patient lie on his or her back and raising their leg while keeping the knee straight. The patient is asked to raise the leg through a number of degrees of angle, and if the patient feels pain when their leg is lifted between a 30 and a 70-degree angle, this is considered a sign that that sciatic nerve is being affected. The test becomes positive for a condition such as a herniated disc around the 5th lumbar nerve, which is a cause of their lower back pain, and likely attributed to sciatica.

The Lasègue Test is quite sensitive to sciatic pain, as the patient will feel the pain in their sciatic nerve when this test is performed. This nerve is a rather large nerve (in fact the largest one in our bodies) that runs from the lower back, down each leg, to the foot. The nerve supports the entire leg and foot, and when something has gone awry with it, the pain can vary from moderate to severe, in a variety of places (usually lower back, but can be symptomatic in the buttocks or leg) and it may be hard to determine what is causing it. The Lasègue Test is specific to finding pain in a certain angle of flexion, and therefor sensitive to the sciatic nerve at the back of the leg. Using the test to determine if your case of lower back or leg pain is indeed sciatica can allow your general practitioner to begin some sort of treatment and get you on your way to minimizing your pain in a timely fashion.