If you search for the actual word you'll get a lot of good explanations and frequently this happens as a result of a fracture: simply, the entire upper vertebral body is abnormally slipped over the vertebral body below. The amount of its slippage is graded on a scale from 1 to 4. Grade 1 is mild (20% slippage), while grade 4 is severe (100% slippage). This often happens after a fracture.
Nerve roots are affected that radiate to other parts of the body and impinge on feelings of heat and cold and the areas that control bowel and bladder. Sometimes the individual cannot tell whether or not there is need to go to the bathroom.
