What is the primary purpose of the straight leg raise test?

What is the primary purpose of the straight leg raise test?

• A. To assess sacroiliac joint dysfunction.
• B. To assess knee ligament integrity.
• C. To screen for lumbar nerve root irritation.
• D. To evaluate hip dislocation.

Answer: (C)

The straight leg raise is used to assess neural tissue tension in the lower spine to detect lumbar nerve root irritation. As the leg is raised while the person is on their back, tension travels along the sciatic nerve and its nerve roots. If this reproduces radicular pain—often down the leg below the knee and following a dermatomal pattern—it suggests irritation or compression of a lumbar nerve root, such as from a disc herniation. A negative result makes lumbar nerve root irritation less likely. This test isn’t meant to evaluate knee ligaments, hip dislocation, or sacroiliac joint dysfunction, which require different maneuvers focused on those structures.

The straight leg raise is used to assess neural tissue tension in the lower spine to detect lumbar nerve root irritation. As the leg is raised while the person is on their back, tension travels along the sciatic nerve and its nerve roots. If this reproduces radicular pain—often down the leg below the knee and following a dermatomal pattern—it suggests irritation or compression of a lumbar nerve root, such as from a disc herniation. A negative result makes lumbar nerve root irritation less likely. This test isn’t meant to evaluate knee ligaments, hip dislocation, or sacroiliac joint dysfunction, which require different maneuvers focused on those structures.