Sciatica is caused by the compression of the spinal nerve roots of the sciatic nerve. The sciatic nerve is a rather large and important nerve that begins in the lower back and goes down both legs. Symptoms of sciatica can include: pain in the lower back, buttocks, or legs; weakness or numbness in those areas; or tingling sensations in the leg.
There are numerous conditions that can lead to or directly cause sciatica. One such cause is spinal disc herniation, commonly known as a “slipped disc.” If the herniated disc presses on one of the nerve roots, this can cause the symptoms of sciatica to occur. Another condition that can cause these symptoms is spinal stenosis, where a narrowing of the spinal canal can cause the compression. Sciatica can also occur during the course of pregnancy, as the weight of the fetus can press against the sciatic nerve.