Sarah Stark (2016)

Keywords: Osteology, Geometric Morphometric, Visualization

Abstract:

Studies of juvenile development are limited by the prevailing methods used to analyze growth trajectories. This paper evaluates the interaction of size and shape of juvenile long bones and teases apart the process of growth and development. Growth is studied by size through linear measurements, while development is examined through shape by geometric morphometrics. This study assesses how geometric morphometrics can be applied to analyze and visualize growth trajectories in the long bones.

A dataset of femora (n=18), tibiae (n=18), and humeri (n=36) from 37 juveniles and adolescents ranging from infancy to twelve years old, was collected from medieval Wharram Percy. Three-dimensional models were created for each element by structured-light-scanning and linear measurements of length and metaphyseal width were recorded. Procrustes (GPA), was used to analyze 10 type I and II landmarks and 100 semi-landmarks.

Morphometric analysis revealed there is significant (p=0.03) difference between age groups for each element. Allometric growth of the humeri showed a steady increase until age 6 and then slowed growth until 12 years old. Interestingly, the femur and tibia showed opposite trajectories as these elements experienced stunted growth after weaning (ages 3-5) and then underwent accelerated growth from 6 to 12 years old. It’s possible that the upper and lower limbs alternated periods of conservative growth as the children from Wharram Percy experienced poor health and environmental stress