Sciatica is a major cause of lower back pain, along with other symptoms such as pain in the buttock, back of the thigh, calf, and foot. Muscle weakness, numbness, or tingling may also occur.
The sciatic nerve is responsible for sending signals to the brain from the muscles; it also acts as a conduit between the legs and the brain to transmit sensory information. Sciatica is often responsible for back pain because the sciatic nerve starts from the lumbar spine (lower back).
Lower back pain caused by sciatica is the result of compression of the sciatic nerve. There are several main factors that lead to compression, including herniated or bulged discs; lumbar spinal stenosis; spondylolisthesis; trauma; pregnancy; and (rarely) spinal tumors.
