Sciatica is the pain in the lower extremity resulting from irritation of the sciatic nerve. The pain of sciatica is usually felt from the lower back (the lumbar area) to behind the thigh and can radiate down below the knee.
The sciatic nerve is the largest nerve in the body and starts from nerve roots in the lumbar spinal cord in the low back and extends through the buttocks area to send nerve endings down the lower limb. The pain of sciatica is sometimes called sciatic nerve pain.
