1. Passive straight-leg raising may induce pain in the back or leg or a combination of both in patients with acute lower lumbar disc lesions. Clinical, myelographic and operative observations were carried out prospectively in fifty such cases to investigate the relation of the pattern of pain on straight-leg raising to the site of the protrusion.

2. In patients with central protrusion straight-leg raising induced mainly back pain. In patients with intermediate protrusion, lying in contact with both dura and nerve root, a combination of back and leg pain predominated. Patients with lateral protrusion usually experienced only pain in the leg. This correlation was found in 80 per cent of cases.

3. Production of pain in the leg by straight-leg raising is of practical significance in lateral protrusions where myelography may be normal.

4. Pain in the back and pain in the leg on straight-leg raising may be related respectively to dural and nerve root sensitivity.