The nature of instability.
(Clinical) instability is that (symptomatic) condition where, in the absence of new injury, a physiologic load induces abnormally large deformations at the intervertebral joint.
D006801:Humans; D007403:Intervertebral Disc / Q000503:physiopathology; D007593:Joint Instability / Q000209:etiology / Q000503:physiopathology*; D008159:Lumbar Vertebrae / Q000503:physiopathology*; D013122:Spinal Diseases / Q000209:etiology / Q000503:physiopathology*; D013314:Stress, Mechanical