morphomap: An R package for long bone landmarking, cortical thickness, and cross-sectional geometry mapping

Objectives This study describes and demonstrates the functionalities and application of a new R package,morphomap, designed to extract shape information as semilandmarks in multiple sections, build cortical thickness maps, and calculate biomechanical parameters on long bones. Methods morphomapcreates, from a single input (an oriented 3D mesh representing the long bone surface), multiple evenly spaced virtual sections.morphomapthen directly and rapidly computes morphometric and biomechanical parameters on each of these sections. The R package comprises three modules: (a) to place semilandmarks on the inner and outer outlines of each section, (b) to extract cortical thicknesses for 2D and 3D morphometric mapping, and (c) to compute cross-sectional geometry. Results In this article, we applymorphomapto femora fromHomo sapiensandPan troglodytesto demonstrate its utility and show its typical outputs.morphomapgreatly facilitates rapid analysis and functional interpretation of long bone form and should prove a valuable addition to the osteoarcheological analysis software toolkit. Conclusions Long bone loading history is commonly retrodicted by calculating biomechanical parameters such as area moments of inertia, analyzing external shape and measuring cortical thickness.morphomapis a software written in the open source R environment, it integrates the main methodological approaches (geometric morphometrics, cortical morphometric maps, and cross-sectional geometry) used to parametrize long bones.

Automated summary

This study introduces a new R package, morphomap, for extracting shape information, building cortical thickness maps, and calculating biomechanical parameters on long bones. It greatly facilitates rapid analysis of long bone form, proving to be a valuable addition to historical analysis software for osteology.