SCIATICA
Sciatica is a set of symptoms including pain that may
be caused by general compression and/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. The pain is felt in the lower back, buttock, and/or various
parts of the leg and foot. In addition to pain, which is sometimes severe, there
may be numbness, muscular weakness, and difficulty in moving or controlling
the leg. Typically, the symptoms are only felt on one side of the body.
Although sciatica is a relatively common form of low back pain and leg pain, the true meaning of the term is often misunderstood. 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
Sciatica is generally caused by the compression of a lumbar spine nerve root
L4 or L5 or sacral nerve roots S1, S2 or S3, or far less commonly, by compression
of the sciatic nerve itself. When sciatica is caused by compression of a lumbar
nerve root it is considered a lumbar radiculopathy (or radiculitis when accompanied
with an inflammatory response) from a spinal disc herniation (a herniated intervertebral
disc in the spine), 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.(1)
source
(1) wikipedia