The trunk model: a multi-segment approach of the thorax

3D motion anlysis is a tool for evaluating gait and posture parameters in orthopaedic deformities. Spinal desorders are very common in paediatric orthopaedic practice. Recently used motion capture methods are not suitable for modeling the kinematics of the trunk segments. The aim of this study was to develop a kinematic model for the trunk that could be applied to measure segmental motions. In the present model the trunk was divided into three parts: the upper thorax, the lower thorax and the pelvis. 13 healthy volunteers were measured to calculate standard graphs for the segmental movements of the trunk. The distance of the C7-Th10 vertebrea, the sagittal- and frontal plane balance and the intersegmental rotation were evaluated. Results of this study present normative values of the trunk motion and highlight the flexibility of the thorax. Our trunk model provide possibility for segmental modeling the trunk in adolescence posture desorders such as scoliosis, Scheuermann’s kyphosis and also in adult spinal diseases. DOI: 10.17489/biohun/2013/1/1