The longest nerve in the body is the Sciatic nerve. It is a single nerve which covers the legs, calves, feet and a part of the lower limb. Damage to the sciatic nerve causes temporary or permanent loss of walking and other forms of similar action. The damaged sciatic nerve is called sciatica. It is not a disease but serious pain that is caused in the leg areas such as thigh, hip and feet. You may have a great difficulty in moving around. Sciatica can occur due to old age, pregnancy or too much of hard work which involves a lot of moving around. Weight lifting is also one cause of obtaining sciatica.