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.
Facet pain is usually caused by degeneration of the cartilage that lines the spinal joints. These joints â called facet joints â are hingelike structures where adjacent vertebrae meet and articulate. In healthy joints, the cartilage provides the smooth surface and padding necessary for movement without friction.