The statistical distribution of members of a population around the population mean. In a gaussian distribution, 68.2% of values fall within Â± 1 standard deviation (SD); 95.4% fall within Â± 2 SD of the mean; and 99.7% fall within Â± 3 SD of the mean. Synonym(s): bell-shaped curve, normal distribution.
Located on the bony extensions of the vertebrae, the surfaces of the facet joints fit together like a three-dimensional puzzle. In the spaces between vertebrae run the nerve rootsâexits off the spinal cord's information highway.
Causes of facet disease. Facet disease may arise when the cartilage in a facet joint is worn down as a result of aging, injury or wear and tear. This type of spinal damage can be attributed to arthritis, work, overuse or an injury sustained in an accident.acet disease occurs when a facet joint degenerates. While this can take place at any level of the spine, it most commonly affects the lumbar (lower spine) region. 1  Facet arthritis. 2  Facet joint syndrome. 3  Facet disease.