Figure 2
From: Reliability study for the Rib Index in chest radiographs of a control group
The description of the RI method. RI is calculated by the ratio of the two distances d1/d2 in LCRs where d1 is the distance between the most extended point of the most extending rib contour and the posterior margin of the corresponding vertebra on the LCRs, while d2 is the distance from the least projected rib contour and the posterior margin of the same vertebra.