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 arthropathy Causes. 1  The real cause of facet arthropathy is yet to be diagnosed but generally it is observed that degeneration of facet joints is the main cause of it. 2  Fracture or torn ligaments may also be a reason. 3  Reduction of space between two vertebrae that compels facet joint to rub against each other.acet arthropathy Causes. 1  The real cause of facet arthropathy is yet to be diagnosed but generally it is observed that degeneration of facet joints is the main cause of it. 2  Fracture or torn ligaments may also be a reason. 3  Reduction of space between two vertebrae that compels facet joint to rub against each other.