Lumbar Disc / Sciatica

Sciatica: lumbar radiculopathy from disc prolapse / spinal stenosis; pain radiating down leg in dermatomal distribution + numbness / weakness. Red flags requiring urgent investigation: • Cauda equina syndrome: bilateral leg pain / weakness, saddle anaesthesia, urinary retention / incontinence, faecal incontinence, reduced anal tone — IMMEDIATE MRI + neurosurgical referral. • Spinal cord compression: UMN signs. • Cancer / infection: weight loss, night pain, fever, IV drug use, immunocompromise, recent infection. • Trauma. Examination: gait, straight leg raise (positive 30–70° = nerve root irritation L4-S1), femoral stretch test (L2-L4), neurology including dermatomes + reflexes + power.