Clinical practice requires that theoretical models of nerve dysfunction be operationalized. This process has resulted in the development of clinical operational models. Selection of outcomes assessments is dependent upon the nature of the model employed by the practitioner. These conceptual models determine the nature of the analytical procedures employed, the type of adjustments applied, and the criteria for determining the success or failure of a given intervention. The segmental model .
Subluxation is described in terms of alterations in specific intervertebral motion segments.
In segmental approaches, the involved motion segments may be identified by radiographic procedures which assess intersegmental disrelationships, or by clinical examination procedures such as motion palpation. Postural approaches . In postural approaches, subluxation is seen as a postural distortion. Tonal approaches . Tone is the normal degree of nerve tension.