[Sciatica or herniated disk].

Lumbar radiculalgia may be due, beside the disc-nerve root conflict, to stenosis of osteoarticular canals, wide dural sac, epidural lipomatosis, segmental arachnoiditis, malignant or benign tumours and meningoradiculitis. Extraspinal truncular or radicular sciatica is usually due to compression by an expansive process. Some types of pain referred from articular structures may mimic sciatica.