Whats the difference between spinal retrolistheses and dislocation?

Degree: A retrolisthesis refers to a usually mild posterior positioning when comparing one vertebrae with the vertebrae above or below it. A dislocation is a much more severe condition and in the spine requires a major trauma to occur. In a dislocation, all contact between the two bones on each side of the joint has been lost: for example a humerus that completely comes out of the shoulder is dislocated.