The Association Between Spinal Posture and Spinal Biomechanics in Modern Humans: Implications for Extinct Hominins

Abstract

The vertebral column is the fundamental body part that determines locomotion and function in vertebrates. Understanding spinal posture, kinetics and kinematics is of great importance to the study of the paleobiology of extinct species. When discussing the biomechanics of the spine of extinct hominins, arguments are based solely on osseous material, as soft tissues are basically absent from the fossil record and because there is no living representative of these species to track and measure movement and function. In this article, we tried to determine the interactions between spinal posture and biomechanics within modern humans and translate the results to extinct hominins. Our main findings indicate that each group/lineage of hominins had special biomechanical characteristics. Early Homo sapiens and Homo erectus with moderate to high spinal curvatures, similar to the posture of modern humans, probably had similar spinal biomechanical characteristics as modern humans. Neanderthal lineage hominins (NLH) with small spinal curvatures might have had somewhat different biomechanics characterized by more stable spine, with reduced shock attenuation abilities compared to modern humans. NLH probably also preferred to squat rather than stoop and had better overhead throwing kinematics compared to modern humans. Australopithecus probably had lumbar biomechanical characteristics within the range of modern humans together with stable cervical spine and a small cervical range of motion (ROM).