The Straight Leg Raise (SLR) test is a common physical examination maneuver used by healthcare professionals to assess lower back and leg pain. It serves as a diagnostic tool, helping identify potential nerve irritation or compression in the lower spine and legs. This is a passive test, meaning the clinician performs the movement while the patient remains relaxed, aiding in diagnosis.
How the Straight Leg Raise Test is Performed
The Straight Leg Raise test begins with the patient lying supine, ideally without a pillow under their head to ensure neutral spinal alignment. The clinician gently lifts the leg by the posterior ankle, keeping the knee fully extended throughout the movement.
The leg is slowly raised, flexing at the hip, until the patient reports symptoms or experiences tightness. The examiner observes the angle at which pain or other symptoms occur, noting their nature and distribution. This passive movement stretches the sciatic nerve and its roots, assessing nerve tension.
Conditions the Straight Leg Raise Test Helps Identify
The Straight Leg Raise test identifies nerve root irritation or compression in the lumbosacral spine. A common condition it suggests is a lumbar disc herniation, which often leads to sciatica by pressing on nearby nerve roots, including the sciatic nerve.
Raising the leg stretches the sciatic nerve and its roots, increasing tension on an already compressed or irritated nerve. This reproduces the patient’s familiar radiating leg pain. The test can also indicate hamstring tightness if pain occurs at angles greater than 70 degrees without radiating symptoms.
Interpreting Straight Leg Raise Test Findings
A “positive” Straight Leg Raise test reproduces the patient’s familiar radiating leg pain, often described as shooting pain, numbness, or tingling. This pain typically occurs when the hip is flexed between 30 and 70 degrees, suggesting nerve root irritation, commonly associated with a lumbar disc herniation.
The angle at which the pain occurs provides clues about the severity or location of nerve compression. For instance, pain at lower angles (e.g., less than 30 degrees) might indicate more acute or severe nerve root irritation. Conversely, if the test causes only back pain without radiating leg symptoms, or pain at higher angles (above 70 degrees), it may suggest hamstring tightness rather than nerve compression. The Straight Leg Raise test is one component of a comprehensive examination, interpreted alongside a patient’s medical history, other physical findings, and sometimes imaging studies to form a complete diagnosis.