True Sciatic or sciatic nerve pain involves the posterior aspect of the thigh, calf or foot and is caused by irritation or compression of a branch of the sciatic nerve, the main nerve into the leg.
Pain may originate where the nerves pas through or emerge from the Lumbar spine or as the nerve passes through the Piriformis muscles in the leg. There maybe numbness or weakness of the lower leg muscles or loss of reflexes.
Sciatic leg pain is often combined with lower back pain. The order in which they appear may vary. Back pain often proceeds leg pain and sometimes will follow.