3-DIMENSIONAL SPINAL COUPLING MECHANICS - PART II - IMPLICATIONS FOR CHIROPRACTIC THEORIES AND PRACTICE

Objective: To compare the current knowledge of 3-D spinal mechanics an d abnormal equilibrium states with chiropractic motion theories, chiro practic vertebral letter listing theories, and chiropractic technique theories. Data Collection: A manual search of available reference text s and a computer search of literature from Index Medicus were collecte d with an emphasis on 3-D studies of human spinal movements, segmental instability, Euler buckling of the spine, and chiropractic theories c oncerning vertebral movements. Results: Previous spinal coupling resul ts based upon two-dimensional radiographic studies are inadequate and inaccurate. Therefore, the validity of any chiropractic technique proc edure, listing, motion analysis or adjusting style based on the two-di mensional radiograph and coupling studies must be questioned. We have identified four types of spinal subluxations (displacements) in the bi omechanical literature: (a) posture main motion and associated segment al coupling, (b) Euler buckling viewed in the anteroposterior view, (c ) snap through viewed in the lateral view and (d) segmental instabilit y. Conclusions: Full three-dimensional investigations of spinal coupli ng patterns have shown that the vertebrae rotate and translate in all three axes and that previous theories of spinal coupling based upon tw o-dimensional studies are inaccurate and invalid. Previous chiropracti c letter listings (e.g., PRI, PLS, etc.) of spinal displacements are i nadequate and invalid. Only one of the four types of biomechanical dis placements, segmental instability, is consistent with the traditional chiropractic theory of segmental spinal displacements; in general, thi s does not respond well to care. In general, vertebrae displacement mu st be viewed in the context of equilibrium configurations and one vert ebra can not be displaced as an individual misalignment. Validity ques tions arise for any technique methods that use letter listings of disp lacement taken from motion palpation or two-dimensional radiographic a nalysis.