Analysis of Morphomics Parameters by Gender and BMI Groups: Thorax Shape and H-point Location

The automotive safety community is questioning the effect of obesity on the performance and assessment of occupant protection systems. This study analyzed CT scan measurements of 10,952 individuals older than 15 years by Body Mass Index (BMI) and gender, including the H‐point location defined relative longitudinal distance between the centroid of the femoral head and the most posterior skin measurement, vertebra‐to‐front‐skin distance, and spine‐to‐back‐skin distance along the sagittal plane. The distance data was obtained at each vertebra level. The average H‐point location increased with BMI and varied with gender. A regression analysis was fitted on the data. For females, it was equal to 55.90 +2.47*BMI in the normal size group, 86.25+1.30*BMI in the obese group, and 116.25+0.55*BMI mm in the morbidly obese group (p<0.01). For males the corresponding H‐point was 64.12+2.11*BMI, 77.28+1.62*BMI, and 95.13+1.17*BMI mm (p<0.01). The vertebra‐to‐front skin and spine-to-back skin distances also increased with BMI and differed with gender. With the increasing worldwide concern for obese occupant protection, test devices representative of this segment of the population are necessary. Human math models provide the best option for a parametric analysis of protection systems designed and optimized for various BMI and gender groups. The morphomic data was analyzed to represent a 5th percentile female and 50th percentile male dummy. These results will be useful in the modifications of the current human mathematical models to represent obese occupants.