Finite Element Model

Objective: To develop a high-fidelity three-dimensional finite element model of the whole spine–thorax complex based on high-resolution computed tomography (CT) images of a healthy adult male, and to perform initial validation under representative loading conditions for quantitative analysis of load transmission, coupled motion, and stress distribution. We hypothesized that the model would reproduce published quasi-static segmental moment–rotation behavior and cadaveric thoracic impact responses within acceptable error ranges. Methods: High-resolution CT data of one healthy adult Chinese male volunteer (25 years; 175 cm; 70 kg) were used to reconstruct detailed anatomical structures, including vertebrae, intervertebral discs, ribs, costal cartilage, sternum, ligaments, respiratory muscles, lungs, and heart. Material properties were assigned based on literature data, and nonlinear contacts were defined among articular and cartilaginous structures. Model validation was carried out using two scenarios: pure-moment loading of the T12–L1 functional spinal unit and a frontal chest impact simulation, with the numerical responses compared against available experimental and cadaveric data. Results: The T12–L1 moment–rotation curves agreed well with published biomechanical ranges, and the frontal impact simulation produced a peak force (3270 N) and chest compression (79 mm) closely matching experimental results (3453 N and 80 mm), with errors of 5.3% and 1.25%, respectively. Conclusions: The finite element model reproduced static and dynamic responses of the spine–thorax complex within available experimental ranges for the loading conditions examined, providing an initial, non-invasive platform for investigating load transmission, coupled motion, and stress distribution under physiological, pathological, and interventional conditions.