A new human spine model for use in cinematographic gait analysis

Purpose: The aim of this study was to compare the accuracy of two spine models: the broken curve model and a new four tangent circles model. The modification concerns the adaptation of data acquisition to kinematic methods used in, e.g., gait and running analysis. Method: Plastic, movable spine model of human with flexible intervertebral disks (manufactured by Erler Zimmer GE3014) was used as the study material. Markers with a diameter of 5 mm were glued to each spinous process (from C₇ to L₅). The recording was performed with a 6-camera Vicon system. Two spine models were created: a broken curve model used, among others, in the Diers scanner, and an own model of 4 circles, similar to the model of circles used in X-ray and CT analysis. Results: The errors in the position of the spinous processes were significantly smaller in the 4-circle model than in the broken curve model. They ranged from 0.01 to 6.5 mm in the lumbar section, from 0.004 to 3.1 mm in the thoracic section. The practical possibilities of using the four-circle model during the cinematographic analysis of gait and run should be checked. Conclusion: The four-circle model is more accurate than the broken curve model and can be used in the cinematographic analysis of the human spine movement.