A generic detailed multibody thoracic spine and ribcage model

Abstract A reliable and comprehensive multibody musculoskeletal model of the thoracic spine and ribcage can offer valuable insight into the biomechanics behind healthy and curved spines. In this study, we developed a generic rigid-body thoracic spine and ribcage model, which is kinematically determinate and controlled by spine posture. A newly devised averaging constraint was implemented to model the individual ribs and the sternum kinematics. The rib motion validation confirmed adjacent ribs’ movement against measured data in different tasks. We simulated 39 adolescent idiopathic scoliosis subjects aged 7–17 years with the average (SD) Cobb angle of 15.2 (8.4) deg. The average errors of multiple scoliosis metrics were less than 4 degrees for angle parameters, 5 mm for displacement parameters, and 3 percent for the ratio parameter. This generic model is simple to use and can simulate a large range-of-motion of daily living activities (e.g., spinal articulation and breathing) and capture pathological deformities conforming to experimentally observed deformations with proper accuracy. It is available to the public in a GitHub repository and will be made available also in the AnyBody Managed Model Repository.