Spinal Pathologies in Fossil Hominins

Abstract

Back disorders are often conjectured to be a trade-off to the evolution of upright bipedalism. Yet, this association has not been substantiated so far. This chapter presents an overview of the known spinal pathologies in the hominin fossil record. Apart from a benign primary bone tumour in MH1 (Australopithecus sediba) and developmental defects in the Middle Pleistocene Pelvis 1 individual from Sima de los Huesos, the Kebara 2 Neanderthal and two individuals from El Sidrón, they include pathologies related to the biomechanical failure of the growing spine and degenerative osteoarthritis. While the latter is particularly common in Neanderthals, biomechanical failure of the growing spine seems to have affected all hominin species. This includes spondylolisthesis in the Pelvis 1 individual from Sima de los Huesos, traumatic juvenile disc herniation in KNM-WT 15000 (Homo erectus), anterior disc herniation (limbus vertebra) in StW 431 (A. africanus), and Scheuermann’s disease in A.L. 288-1 (A. afarensis) and three isolated thoracic vertebrae from Hadar, Sts 14 (A. africanus), SKX 3342 (Paranthropus robustus), the Pelvis 1 individual from Sima de los Huesos and perhaps Kebara 2 and Shanidar 3. Juvenile disc herniation, traumatic anterior disc herniation and Scheuermann’s disease all involve displacement of disc material and have a higher incidence following strains and trauma to the spine during the increased vulnerability phase of the pubertal growth spurt. The remarkably high prevalence of this kind of disorders in our ancestors might suggest that our spine has become less vulnerable during the course of human evolution.