Originally published in 1933, this book is a culmination of a lifetime of research by Hans Friedrich Gadow into the evolution of the vertebrae. Gadow outlines the various forms of vertebral development as a guide to larger and more general questions on the morphological scheme of the evolution of vertebrate creatures, and uses plentiful diagrams, photographs and reconstructions to trace spinal development. This book will be of value to anyone with an interest in the history of science.
The vertebral spine is a key element of the human anatomy. Its main role is to protect the spinal cord and the main blood vessels. The axial skeleton, with its muscles and joints, provides stability for the attachment of the head, tail and limbs and, at the same time, enables the mobility required for breathing and for locomotion. Despite its great importance, the vertebral spine is often over looked by researchers because: a) vertebrae are fragile in nature, which makes their fossilization a rare event; b) they are metameric (seriated and repeated elements) that make their anatomical determination and, thus, their subsequent study difficult; and c) the plethora of bones and joints involved in every movement or function of the axial skeleton makes the reconstruction of posture, breathing mechanics and locomotion extremely difficult. It is well established that the spine has changed dramatically during human evolution. Spinal curvatures, spinal load transmission, and thoracic shape of bipedal humans are derived among hominoids. Yet, there are many debates as to how and when these changes occurred and to their phylogenetic, functional, and pathological implications. In recent years, renewed interest arose in the axial skeleton. New and exciting finds, mostly from Europe and Africa, as well as new methods for reconstructing the spine, have been introduced to the research community. New methodologies such as Finite Element Analysis, trabecular bone analysis, Geometric Morphometric analysis, and gait analysis have been applied to the spines of primates and humans. These provide a new and refreshing look into the evolution of the spine. Advanced biomechanical research regarding posture, range of motion, stability, and attenuation of the human spine has interesting evolutionary implications. Until now, no book that summarizes the updated research and knowledge regarding spinal evolution in hominoids has been available. The present book explores both these new methodologies and new data, including recent fossil, morphological, biomechanical, and theoretical advances regarding vertebral column evolution. In order to cover all of that data, we divide the book into four parts: 1) the spine of hominoids; 2) the vertebral spine of extinct hominins; 3) ontogeny, biomechanics and pathology of the human spine; and 4) new methodologies of spinal research. These parts complement each other and provide a wide and comprehensive examination of spinal evolution.
Although it is the defining organ of the Chordata, the notochord and its cells are one of the least understood vertebrate organs. This may be because large parts of the notochord are often replaced with cartilaginous or bony vertebral bodies. The presence of cartilage in the notochord raises questions about the evolutionary relationships between notochord cells and cartilage cells. This book integrates classical analytical studies with recent palaeontological, experimental, and molecular studies in both developmental and evolutionary contexts. For example, although the early signaling function of the notochord is conserved across the vertebrates, many will be surprised to find that the role of the notochord in vertebral body development in tetrapods is not the blueprint for all vertebrates. Recent studies on zebrafish and medaka embryos have uncovered the molecular mechanisms of a somite-independent notochord-driven segmentation process that establishes vertebral centra and intervertebral spaces. As this process is not restricted to teleosts, the authors have written a general discussion about the role of the notochord in vertebral formation. Modularity and segmentation of the vertebral column are related topics. Further overarching themes are the structure, function and fate of the notochord in adult vertebrates and notochord–cartilage relationships. Key Features The first book devoted to notochord development, function and evolution Includes and integrates information on the notochord from studies going back 169 years Integrates developmental, molecular, functional, experimental and palaeontological studies Documents the fate of the notochord across the vertebrates Extensively illustrated with classical and new images Related Titles Bard, J. Evolution: The Origins and Mechanisms of Diversity (ISNB 978-0-3673-5701-6) Leys, S. and Hejnol. A. Origin and Evolution of Metazoan Cell Types (ISBN 978-1-1380-3269-9)
This is a study of the numerical composition of the vertebral column, the central structure of the vertebrate body plan and one that plays an instrumental role in locomotion and posture. Recent models of hominoid vertebral evolution invoke very different roles for homology and homoplasy in the evolution of vertebral formulae in living and extinct hominoids. These processes are fundamental to the emergence of morphological structures and reflect similarity by common descent (homology) or similarity by independent evolution (homoplasy). Although the "short backs," reflecting reduced lumbar regions, of living hominoids have traditionally been interpreted as homologies and shared derived characters (synapomorphies) of the ape and human clade, recent studies of variation in extant hominoid vertebral formulae have challenged this hypothesis. Instead, a "long-back" model, in which primitive, long lumbar regions are retained throughout hominoid evolution and are reduced independently in six lineages of modern hominoids, is proposed. The recently described skeleton of Ardipithecus ramidus is interpreted to support the long-back model. Here, larger samples are collected and placed in a larger phylogenetic context than previous studies. Analyses of over 8,000 mammal specimens, representing all major groups and focusing on anthropoid primates, allow for the reconstruction of ancestral vertebral formulae throughout mammalian evolution and a determination of the uniqueness of hominoid vertebral formulae. This survey, in combination with analyses of intraspecific diversity and interspecific similarity, suggests that reduced lumbar regions are homologous in extant hominoids. Furthermore, hominoid vertebral formulae are unique among primates and relatively unique among mammals in general. Hominins likely evolved five lumbar vertebrae from a short-backed ancestor with an "African ape-like" vertebral profile. By the appearance of Australopithecus, hominins evolved a cranial placement of the diaphragmatic (one that bears a change in articular facet orientation) vertebra, which generates a functionally longer lower spine while maintaining five lumbar vertebrae. In light of these findings, it is proposed that bipedalism evolved in a party arboreal, partly terrestrial African ape-like locomotor context.
This book offers essential guidance on selecting the most appropriate surgical management option for a variety of spinal conditions, including idiopathic problems, and degenerative disease. While the first part of the book discusses the neuroanatomy and biomechanics of the spine, pain mechanisms, and imaging techniques, the second guides the reader through the diagnostic process and treatment selection for disorders of the different regions of the spine, based on the principles of evidence-based medicine. I.e., it clearly explains why a particular technique should be selected for a specific patient on the basis of the available evidence, which is carefully reviewed. The book identifies potential complications and highlights technical pearls, describing newer surgical techniques and illustrating them with the help of images and accompanying videos. Though primarily intended for neurosurgeons, the book will also be of interest to orthopaedic surgeons, specialists in physical medicine, and pain specialists. ​
The primate vertebral skeleton has been studied intensively by morphologists for more than a century and has become a focal point of investigation in biological anthropology. However, several issues regarding vertebral homology and anatomy remain controversial. I collected metric and non-metric data on 392 cercopithecine and hominoid spines to answer the following questions: First, what is the homology of the lumbar transverse process (LTP) in catarrhines? Second, how many lumbar vertebrae do early hominids possess? Third, how do last rib length, LTP width, and sacral width covary in catarrhines? Methods included data collection by caliper measurement as well as statistical tests such as ANCOVA. I conclude that all catarrhine primates share a similar LTP homology, in which the LTP is composed of a rib element ventrally and derivative of the thoracic transverse process dorsally. Based on these findings, I show that the early hominid specimens Sts 14 and Stw 431 possessed a minimum of six functional lumbar vertebrae. In the metric comparisons, I find that humans have relatively short last ribs; that, in addition to their relatively narrow sacra, the African apes have narrow penultimate and ultimate lumbar vertebrae; and that the early hominids Sts 14 and AL 288-1 have the relatively widest LTPs and sacra of the taxa studied. Incorporating all these data, I present a model of hominoid lumbar vertebral evolution in which each of the great apes has independently evolved a short lumbar spine of three to four segments. Therefore, the long lumbar column of early hominids was most likely a primitive retention, and it is not derived as is commonly assumed.
