Tono O, et al. - Authors tested the presumption that the relationship between PI and L1–S1 lumbar lordosis (LL) is always positive, even in cases with different lumbar sagittal profiles. They stratified the subjects into three groups: the upper group with an apex between L1 and L3 (UppA, n=19), the middle group with an apex from L3/4 to L4/5 (MidA, n=67), and the lower group with an apex at L5 or below (LowA, n=14). Contrary to the hypothesis, in the cases with apex above L3, association between PI and LL was not significant. This suggested to take into account the whole sagittal alignment as the relationship between PI and LL is not always constant. Findings suggested a positive significant association of LL and PI in the MidA and LowA groups, but not in the UppA group.