A positive straight-leg raise test most specifically indicates radiculopathy due to irritation of which structure?

• A. Radiculopathy due to lumbar nerve root irritation
• B. Spinal compression
• C. Degenerative disc disease without nerve root involvement
• D. Sacroiliac joint dysfunction

Answer: (A)

A positive straight-leg raise indicates radiculopathy from irritation of a lumbar nerve root. When the leg is raised, the neural tissues in the lumbosacral tract are stretched; if a disc herniation or other lesion compresses or irritates a lumbar root (most commonly L5–S1), this stretch reproduces pain that radiates down the leg along a dermatomal pattern. That leg pain, often below the knee, points to nerve-root involvement rather than isolated back strain. Spinal canal compression can cause neuro symptoms but the straight-leg raise specifically highlights nerve-root irritation from the lumbar region. Degenerative disc disease without nerve involvement and sacroiliac joint dysfunction typically do not produce true radicular leg pain in the same pattern.