Straight leg raise

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Straight leg raise (SLR), also known as the Lasegue's test, is a medical test used to assess the presence of sciatica and other conditions related to lumbar disc herniation. The test is performed during a physical examination and is considered a key diagnostic tool in evaluating patients with lower back pain and leg pain.

Procedure

The straight leg raise test is typically performed with the patient lying in a supine position. The examiner lifts the patient's leg while keeping the knee straight. The test is positive if the patient experiences pain along the distribution of the sciatic nerve, typically between 30 and 70 degrees of hip flexion. Pain that radiates below the knee is often indicative of nerve root irritation, commonly due to a herniated disc at the L4-L5 or L5-S1 levels.

Clinical Significance

A positive straight leg raise test suggests the presence of lumbar radiculopathy, which is often caused by a herniated disc compressing a nerve root. The test can help differentiate between musculoskeletal pain and neuropathic pain. It is also used to evaluate the severity and level of nerve root involvement.

Variations

There are several variations of the straight leg raise test, including:

• Crossed Straight Leg Raise Test: This variation involves lifting the unaffected leg. A positive result, where pain is elicited in the affected leg, is highly specific for lumbar disc herniation.
• Seated Straight Leg Raise Test: Performed with the patient seated, this test can be used when the supine test is not feasible.

Interpretation

The results of the straight leg raise test should be interpreted in conjunction with other clinical findings and diagnostic tests, such as magnetic resonance imaging (MRI) or computed tomography (CT) scans. A positive test alone is not sufficient for a definitive diagnosis but can guide further investigation and management.

Related Tests

• Bragard's sign
• Bowstring sign
• Slump test

See Also

• Sciatica
• Lumbar disc herniation
• Physical examination
• Neuropathic pain
• Musculoskeletal pain