Sciatica is irritation of the sciatic nerve that passes down the back of each thigh.

The sciatic nerve arises from the lower spine on either side and travels deep in the pelvis to the lower buttocks. From there, it passes along the back of each upper leg and divides at the knee into branches that go to the feet.

Sciatica typically causes pain that shoots down the back of one thigh or buttock. Sciatica pain is often burning, tingling, or numbness on one side of the leg. Pain may also be present on one side of the buttocks that worsens when seated for a long time.

Sciatic Nerve Pain
Sciatica Nerve Pain
© 2009 Nucleus Medical Media, Inc.

Anything that causes irritation or puts pressure on the sciatic nerve can cause sciatica, including:

  • Herniated disk (or slipped disk)—the cushions between the bones of your spine bulge out of place and press on the nerve as it exits the spinal column
  • Disk degeneration—caused by aging or arthritis
  • Spinal stenosis —narrowing of the spinal canal in the lumbar area
  • Spondylolisthesis —slippage of a bone in the low back
  • Sprain or strain of muscles or ligaments in the area
  • In rare cases:
    • Benign or malignant tumors
    • Infections
    • Blood clots
    • Metabolic problems like diabetes
    • Toxins, such as excessive alcohol