A multifaceted exploration of ontogenetic variation in vertebral neural canal size across contemporary populations

Abstract

OBJECTIVES : Vertebral neural canal (VNC) dimensions are considered a reliable indicator of childhood stress. However, no study has characterized variation in VNC size or shape or the impact of extrinsic or intrinsic factors on their range of variation. The present study explores VNC dimensions of subadult samples varying in chronology, population of origin, geography, and socioeconomic backgrounds. MATERIALS AND METHODS : Antero-posterior (AP) and transverse (TR) diameters were measured on the tenth thoracic to the fifth lumbar vertebrae of 1404 contemporary individuals aged between birth and 22 years from Colombia (N = 28), France (N = 484), the Netherlands (N = 23), Taiwan (N = 31), and the United States (N = 838), and compared to lumbar diameters of subadults from the Spitalfields collection (N = 84) and the East Smithfield cemetery (N = 65). VNC variation was evaluated with skeletal growth profiles, principal component analyses (PCA), MANOVAs and ANOVAs. RESULTS : AP diameter growth ends during childhood, while TR diameter growth progressively slows before ending in adolescence. The Colombian sample presented the smallest VNC diameters compared to the other contemporary and historic samples. VNC shape (AP/TR ratio) was similar in contemporary samples. MANOVAs and ANOVAs revealed significant differences in VNC size according to country of origin and socio-economic status, primarily differentiating the Colombian sample. DISCUSSION : The overall consistency in size and shape among groups is remarkable. While physiological stress may contribute to variability in VNC size, intrinsic ontogenetic processes and other individual and environmental factors also influence variability in VNC size.