The term sciatica refers to pain in the leg. The sciatic nerve is a large nerve running down the back of your leg. It simply has its own name because it is fairly common and easy to understand. Sciatica is used to describe the pain that travels from the sciatic nerve in the lumbar region into your buttocks, back of the thighs, and sometimes calf and foot.
The pain is typically caused by irritation of the nerve roots that join outside the spine to make up the sciatic nerve. Conditions that can cause sciatica are: herniated discs, bone spurs, stenosis, infection, cancerous tumors, and fractures that put pressure on the nerves