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Three-dimensional spinal coupling mechanics: Part II. Implications for chiropractic theories and practice
D E Harrison1, D D Harrison, S J Troyanovich
1Department of Mathematics, University of Alabama, Huntsville, USA.
Summary
Current chiropractic theories on spinal mechanics are challenged by 3-D research. Two-dimensional studies are inaccurate, questioning the validity of chiropractic vertebral listing and motion analysis techniques.
Area of Science:
- Biomechanics
- Spinal Mechanics
- Chiropractic Research
Background:
- Traditional chiropractic theories often rely on 2-D analyses of spinal movement.
- Previous studies on spinal coupling were primarily based on 2-D radiographic data.
Purpose of the Study:
- To compare current 3-D spinal mechanics knowledge with chiropractic theories.
- To evaluate chiropractic vertebral motion, listing, and technique theories against biomechanical evidence.
Main Methods:
- Manual and computer-based literature searches were conducted.
- Emphasis was placed on 3-D studies of human spinal movements, segmental instability, and Euler buckling.
- Chiropractic theories on vertebral movements were included for comparison.
Main Results:
- Two-dimensional spinal coupling studies are inadequate and inaccurate.
- Four types of spinal displacements identified: posture motion, Euler buckling, snap through, and segmental instability.
- Chiropractic vertebral listing theories are inadequate and invalid based on 3-D data.
Conclusions:
- Full 3-D spinal investigations reveal vertebrae rotate and translate in all three axes.
- Previous 2-D spinal coupling theories are inaccurate.
- Only segmental instability aligns with traditional chiropractic theory, but it generally responds poorly to care.
- Chiropractic techniques relying on 2-D analysis or motion palpation listings are questionable.