Costal cartilage plays an important role in the structural stiffness of the ribcage as segments that flexibly connect the bony ribs to the sternum. Calcification of costal cartilage occurring throughout adult life can substantially change local material properties and stiffen the structural mechanical response. Current finiteelement (FE) human body models (HBMs) have a simplified representation of costal cartilage with homogeneous material properties, yet the FE meshes allow for discrete regions within a given mesh to be modeled using separate materials. To represent costal cartilage and its calcification across the population, this study proposed a consistent indexing system shared between HBMs as well as the real humans they represent. In this system, spatial positions in the costal cartilage are identified using a continuous coordinate space. This study also proposed a modeling framework to represent costal cartilage calcification in multiple models in a consistent fashion with real human data. This study successfully applied the indexing system to several current commercial FE HBMs and tested the ability of the framework with a limited set of real human data. The indexing system and modeling framework are expected to be a precursor to future study on the influence of calcification on mechanical responses of the ribcage.