The vertebral subluxation : a compromised follower load?

Objective: To develop a theoretical and clinical model based on tangential (follower) loading as a method of optimal force transmission in the spine to explain the traditional chiropractic concept of a vertebral subluxation and as a description and rational for the clinical entity that has been the object of chiropractic manipulative therapy (adjustment). Method: A brief review of the literature and relevant texts relating to the application of the mechanical concept of follower and tangential loads to the spine and the chiropractic concept of the vertebral subluxation was undertaken to determine common factors and inter-related components. Results: Relevant information from the literature relating to follower and tangential loading of the spine, vertebral subluxations and manipulation was correlated and synthesised into a model describing normal spinal mechanics and the loss of mechanical integrity of the spine. The model was developed as a theoretical basis for the chiropractic concept of the vertebral subluxation and as a mechanical rationale for spinal manipulation. Three key components were identified that were common to follower and tangential loads, subluxations and manipulation of the spine and were incorporated into the model. These involved active components, passive elements and feedback mechanisms previously described by Panjabi. Conclusion: The mechanical concepts underlying tangential loading of the spine have been applied to the chiropractic concept of the vertebral subluxation and spinal adjustment. Load theory and research provides chiropractic with a testable hypothesis for the clinical response to the adjustment and a theoretical basis for the subluxation as a clinical entity