PRELIMINARY-STUDY OF THE HUMAN LUMBAR SPINE USING SPECKLE TECHNIQUE -LIMITS OF COMPRESSION, SHEAR AND TORSION - SPECKLE PHOTOGRAPHY - ELECTRONIC SPECKLE PATTERN INTERFEROMETRY

Optical techniques using single wavelength lasers allow precise study of the superficial displacements of deeper anatomical structures throu gh direct mechanical pull. Two techniques have been used in this study : 1. Double exposure speckle photography. Since 1980 the relationship between the surface displacements and minimal traction applied to the transverse processes of the spine, either unilateral or bilateral, was studied in an attempt to simulate muscular action exerted at this lev el. 2. Computerised speckle interferometry. This allowed analysis of t he deformations between the lumbar vertebrae under vertical compressio n, shear or torsion outside the usual anatomical planes. This prelimin ary study outlines the mechanical behaviour and the plasticity of the vertebral structures but has been performed on only a few anatomical s pecimens thus not allowing statistical analysis. This would require a larger series.