Abstract:

Abstract： The threedimensional finite element model of lumbar vertebrae(L₄-L ₅) with similar geometrical structure and material character, which can be used to analyze lumbar vertebrae biomechanics for the lumbermen using chain saw in forest harvesting. The research studied von mises tress on the vertebrae,intervertebral disc and zygapophysial joint while the lumbermen stoop and stand, the results were following: stress concentration at inervertebral disc was found at middleposterior location of exterior annulus fibrosus, posterior location in flexion especially evident. Von mises stress at vertebral body is higher than that of the below nucleus pulposus, von mises stress at the endplate of adjacent vertebral body is higher than that of other location, the stress focused on around vertebrae arch of compact bone and adjacent endplate, stress concentration occurs at up and down articular processes of facet joints and pedicle of vertebral arch, for the posterior structure of vertebrae. When the lumbar vertebrae was subjected vertical compression, for the intervetebral disc, the stress concentration at the posteriorexterior location, the max von mises tress focused on center of adjacent endplate of spongy bone, anterior and anteriorbelow vertebral body, there is easy catagmatic location of cuniform compressibility fracture, the same to up and down articular processes of facet joints.

Key words: Key words： three dimensional reconstruction, finite element model, biomechanics, lumbar spine, chain saw