Effects of moment arms on spinal stability subjected to follower loads: A finite element analysis study

Finite element analyses have been widely used in biomechanical research. However, in order to improve the confidence of the analysis, it is necessary to understand the dependence of the analysis results on anatomical data. In this paper, the effect of a moment arm between a body center and an attachment point of muscle in each vertebra on the spinal stability was investigated. A two-dimensional finite element model of the musculoskeletal system of a lumbar spine was developed in the frontal plane. An optimization method was implemented to analyze the joint forces and moments with the muscle forces subjected to a follower load condition. Moment arms significantly affected the tilts of the deformed shape of the model and resultant joint moment.