Sciatica is the sensation of pain, tingling or numbness in the buttocks and or legs produced by an irritation of the sciatic nerve. Multiple nerve roots extend from each side of the spinal cord in the sacral area (right above the tail bone), and join to form the sciatic nerve. The sciatic nerve actually only exists for a short length down the buttock, after which branches into various nerves. The smaller nerve branches then travels down the leg, reaching the ankle and foot. The primary causes of sciatica are herniated, buldging, or degentereated discs, which put pressure on the spinal nerve roots. Other causes include bony growths on the spine (bone spurs) or compression of the nerves through injury. In rare cases, the sciatic nerve may be irritated by conditions such as tumors, pregnancy, or piriformis syndrome.