It is common in middle aged and older men. Causes include degenerative changes, trauma, neck/back strain. Most common (95%) is in lumber region especially at L5-S1. History: * Patient presents with severe, electricity-like lower back pain, usually preceded by several months of aching, 'discogenic' pain. * ⬆️Pain = by inc. intra-abdominal pressure = by passive straight leg raise = by crossed straight leg raise * Associated with sciatica, paresthesias, muscle weakness or spasm. * Large midline herniations can cause cauda equina syndrome which is a surgical emergency. Diagnosis: * By positive passive straight leg raise. * MRI is the preferred test. * Obtain ESR and plain x ray if other causes of lower back pain are suspected. Treatment: * Best initial treatment is NSAID in scheduled doses, physical therapy and local heat. * Epidural steroid injection or nerve block is useful in cases not responding to initial therapy. * Surgery is most definitive treatment.