Sorting Out Sciatica

The sciatic nerve starts as a collection of nerve fibers at the lower portions of the spine-the bottom segments of the lumbar spine (L4 and L5) and the top segment of the sacral spine (S1 to S3). The nerves exit the spinal canal and come together to form the large sciatic nerve, which then runs below a muscle in the buttocks (the piriformis muscle) and down the back of the thigh. Above the knee, the nerve separates into two nerves, which extend down to thefoot.