Sciatica is a term that refers to the painful inflammation of the sciatic nerve, the longest and largest nerve in your body. The sciatic nerve extends from your buttocks all the way down to your toes. This nerve is formed from five nerve roots in your lower back which join together deep in the pelvis. From there, the sciatic nerve divides into many branch nerves that serve your muscles, joints, skin, and other tissues in your legs and feet. The sciatica may or may not involve low back pain. Sciatica can be caused by many conditions including disc bulges/herniations and piriformis muscle injuries.