You develop sciatica when you have a pinched sciatic nerve. The sciatic nerve leaves the spinal cord near the base of your spine and travels down both sides of your body, going through your buttocks and down each leg.

You may pinch the nerve following an injury, but sciatica most frequently develops due to spine conditions such as:

  • Herniated disc
  • Spinal stenosis
  • Facet joint arthritis
  • Degenerative disc disease
  • Bone spurs

Though not as common, muscles in your buttocks can also pinch the nerve when they spasm. This condition, called piriformis syndrome, causes the same symptoms as sciatica.