What is a potential limitation of the straight leg raise test when considering disc herniation?

• A. A negative result definitively excludes disc herniation.
• B. A positive result is always specific to disc herniation.
• C. A positive test may occur with non-disc pathology.
• D. The test has no clinical value.

Answer: (C)

The straight leg raise looks for nerve root irritation by lengthening the sciatic nerve and its roots, so a positive result can suggest radicular involvement often seen with disc herniation. But its limitation is lack of specificity: a positive test can occur with non-disc pathologies that irritate the same nerve roots, such as spinal stenosis, facet or degenerative changes, foraminal encroachment, lumbar strain with nerve irritation, or other compressive/inflammatory conditions like piriformis syndrome. Because of this, a positive straight leg raise does not definitively diagnose disc herniation and must be interpreted alongside the overall clinical picture and, if needed, imaging.