Sciatica is a set of symptoms, not a diagnosis, including pain that may be caused by general compression or irritation of one of five nerve roots that give rise to the sciatic nerve, or by compression or irritation of the sciatic nerve itself.
Typcially pain is felt in the lower back, buttock, and/or various parts of the leg and foot. In addition there may be numbness, muscular weakness, pins and needles or tingling and difficulty in moving or controlling the leg. Typically, the symptoms are only felt on one side of the body.
If you are experiencing symptoms in both legs and have had changes in bowel function or bladder control seek medical help immediately.
Although sciatica is a relatively common form of low back pain and leg pain, the cause of your symptoms must be properly diagnosed. Sciatica is a set of symptoms rather than a diagnosis for what is irritating the root of the nerve, causing the pain. This point is important, because treatment for sciatica or sciatic symptoms will often be different, depending upon the underlying cause of the symptoms.
Causes of Sciatica
Sciatica is generally caused by the compression of lumbar nerves L4 or L5 or sacral nerves S1, S2 or S3, or far less commonly, by compression of the sciatic nerve itself. When sciatica is caused by compression of a nerve root it is considered a lumbar radiculopathy. Sciatica from a spinal disc herniation, or from roughening, enlarging, and/or misaligning of the vertebrae (spondylolisthesis), or degenerated discs. Sciatica due to compression of a nerve root is one of the most common forms of radiculopathy.
Sciatic like ymptoms similar to spinal nerve root compression can also occur and this, usually, is caused by the compression of peripheral sections of the nerve, usually from soft tissue tension in the piriformis or related muscles and is called piriformis syndrome.
Depending on which nerve roots are involved sciatic symptoms may prenset as such:
Following is a vdeo tutorial that further shows the mechanisms of sciatica: