Surface strain distribution in isolated single lumbar vertebrae

lumbar vertebrae. The surface strains of isolated single lumbar vertebrae under com-pressive load were examined by the techniques of brittlecoat and photoelastic analysis. Directions of principal strain components have been determined. Areas of stress concen-tration were found around the vertebral rims, near the pedicles, and around the foramina of the basivertebral veins. The human spine in life is subjected to a bewildering combination of shear, torsion, compression, and tensile forces. This paper attempts to identify the principal directions of strain and areas of high strain concentration in isolated vertebrae loaded in a simple compressive force system. While accepting that the experimental conditions are vastly different from those occurring in vivo, such knowledge may assist in the understanding of the mechanical role of the spine, and indicate ways in which stress-induced damag