Compartmentalization Index: Description and Applications in Anthropological Studies

Abstract

Objectives: The cross-sectional area occupied by mineralized tissues is so high in non-adult individuals that linear methodsprovide limited information about its variation along their bones. This issue can be addressed using the compartmentalizationindex, a non-linear index that amplifies differences in cross sections with more than 90% of the mineralized area. Materials and Methods: We selected five femur diaphyseal cross sections of 35 non-adult Homo sapiens individuals fromperinatal to 5 years old. Then we measured the percentage of mineralized area of each section and calculated the correspondingcompartmentalization index. Subsequently, the distribution of both measurements was graphically tested. Results and Discussion: As expected, variations of femur diaphyseal mineralized areas are visually magnified using the com-partmentalization index for values exceeding 90%, but the significance of statistical comparisons between groups is not affected. This makes the index particularly useful for exploring subtle variations in the early stages of growth and development. In addi-tion, we found that using either the compartmentalization index or direct percentage measurements is equally effective for crosssections with lower mineralized area, as the data distributions are comparable. This also allows applying the compartmentaliza-tion index in research focused exclusively on adult individuals.