Intervertebral dysfunction refers to a biomechanical fault which is abnormal in both its dynamic and static components. A subluxation may be considered as being fixated and also slightly malpositioned in one or more axes of rotation. Subluxation may be considered as one component of a complex or syndrome of intervertebral dyskinesia, dysarthrosis or dysfunction. The biochemical and histological components explain some of the pain mechanisms, tissue changes and residual effects of acute and chronic intervertebral fixation and the need for repeated spinal manipulations and prolonged care. Interexaminer reliability studies indicate that a standard method of motion palpation is quite feasible and accurate. X-ray evidence of dyskinesia shows promise as a means of documenting subluxation fixations.