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The Backbone of Moche Society: Spinal Degenerative Joint Disease and Differentiating Social Stratification at San Jose de More, Peru BY Matthew C. Go A thesis submitted in partial fulfillment of the requirements for the degree of BACHELOR OF ARTS HONOURS in the Department of Archaeology © Matthew C. Go 2013 SIMON FRASER UNIVERSITY Fall 2013 ABSTRACT This investigation seeks to explore variation in the quality of life among Late Moche individuals at San Jose de Moro, Peru, as reflected in the severity of spinal degenerative joint disease (SDJD). San Jose de Moro is a protected archaeological site located on the north coast of Peru. Prehistoric occupation spans from the Middle Moche Period (AD 100) until Chimu-Inca times. However, the focus of this research is the Late Moche Period (AD 700-800). Spinal degenerative joint disease in the skeletal remains is used as an indicator of the relative quality of life the individual had endured. The vertebral elements were examined at several spinal joints for lesions indicative of SDJD including marginal osteophytes, lipping, surface pitting, sclerotic new bone formation, eburnation and Schmorl’s nodes. Specific vertebral articulations analyzed were individual zygapophyseal facets, and intervertebral symphyses. Severity was visually assessed through an ordinal scale of 0 – 3. Individuals were categorized by age and sex in order to control for these variables. The relationship between spinal health, social status and sex is explored. Analysis suggests young adults are similar to middle to older adults, except for a greater severity in the cervical spine in the latter. Males show an overall severity across the spine, while females have isolated severity in the cervical and lumbar regions. Commoners possess greater overall SDJD lesion severity compared to higher ranking individuals. The current study represents the first formal attempt with an osteological focus to investigate Late Moche social stratification at San Jose de Moro, Peru. i ACKNOWLEDGEMENTS The biggest gratitude must go to Dr. Deborah Merrett, my supervisor, whose guidance has brought me through the largest challenges of this endeavor. I am also indebted to Dr. Luis Jaime Castillo-Butters, director of the San Jose de Moro Archaeological Project, who granted me access to the material in this study and accommodated me in the field. To Elsa Tomasto and Melissa Lund, Peruvian bioarchaeologists and mentors, whose support and advice during the collection of this data kept me motivated and excited during my time there. To the rest of the members of the PASJM team whom are also my dear friends: Solsiré Cusicanqui Marsano, Julio Saldaña, María Claudia Herrera, Karla Patroni, among many more, thank you for your swift and heartfelt assistance in logistic and administrative matters. To my many friends scattered across the world, thank you for the emotional encouragement during my episodes of almost certain despair. And lastly, to my parents, Wend and Margaret, thank you most of all for your unwavering faith in my abilities and undying sacrifice to provide me with a better future. ii TABLE OF CONTENTS ABSTRACT ...................................................................................................................................... i ACKNOWLEDGEMENTS ............................................................................................................. ii TABLE OF CONTENTS ................................................................................................................ iii LIST OF FIGURES ......................................................................................................................... v LIST OF TABLES ......................................................................................................................... vii CHAPTER 1: INTRODUCTION ................................................................................................. 1 1.1 Introduction ............................................................................................................................ 1 1.2 Purpose of the Study............................................................................................................... 1 1.3 Thesis Outline ........................................................................................................................ 2 CHAPTER 2: ON THE INTERPRETATION OF SKELETAL LESIONS ............................. 3 2.1 Introduction ............................................................................................................................ 3 2.2 The Osteological Paradox ...................................................................................................... 3 2.3 Responses to the Osteological Paradox .................................................................................. 5 2.4 Osteoarthritis in Light of the Osteological Paradox ............................................................... 7 2.5 Summary ................................................................................................................................ 8 CHAPTER 3: OSTEOARTHRITIS AND JOINT BIOLOGY .................................................. 9 3.1 Introduction ............................................................................................................................ 9 3.2 Synovial Joint Biology ........................................................................................................... 9 3.3 The Aetiology and Pathogenesis of Osteoarthritis ............................................................... 10 3.4 The Progression and Diagnosis of Osteoarthritis ................................................................. 13 3.5 Osteoarthritis and Other Diseases ........................................................................................ 14 3.6 Summary .............................................................................................................................. 15 CHAPTER 4: SPINAL DEGENERATIVE JOINT DISEASE ............................................... 17 4.1 Introduction .......................................................................................................................... 17 4.2 Anatomy of the Spine ........................................................................................................... 17 4.3 Degeneration of the Spine .................................................................................................... 20 4.4 Diagnosing Spinal Degenerative Joint Disease .................................................................... 22 4.5 Limitations to the Study of Spinal Degenerative Joint Disease ........................................... 22 4.6 Summary .............................................................................................................................. 24 CHAPTER 5: THE ARCHAEOLOGICAL CONTEXT OF SAN JOSE DE MORO .......... 25 5.1 Introduction .......................................................................................................................... 25 5.2 Environmental Context......................................................................................................... 26 5.3 Chronology ........................................................................................................................... 26 5.4 Sociopolitical Organization .................................................................................................. 27 5.5 Social Stratification and Burial Contexts ............................................................................. 29 5.6 Moche Collapse .................................................................................................................... 31 5.7 Summary .............................................................................................................................. 32 iii CHAPTER 6: MATERIALS AND METHODS ....................................................................... 34 6.1 Materials ............................................................................................................................... 34 6.1.1 Time Period ................................................................................................................... 34 6.2 Methods ................................................................................................................................ 35 6.2.1 Diagnostic Criteria ......................................................................................................... 36 6.2.2 Points of Observation .................................................................................................... 38 6.2.3 Age and Sex Estimation................................................................................................. 38 6.2.4 Social Status................................................................................................................... 38 6.2.5 Preservation ................................................................................................................... 39 6.2.6 Statistical Methods......................................................................................................... 39 CHAPTER 7: RESULTS ............................................................................................................ 40 7.1 Introduction .......................................................................................................................... 40 7.2 Zygapophyseal Facets .......................................................................................................... 40 7.3 Vertebral Bodies ................................................................................................................... 42 7.4 Summary .............................................................................................................................. 44 CHAPTER 8: DISCUSSION ...................................................................................................... 45 8.1 Introduction .......................................................................................................................... 45 8.2 Age ....................................................................................................................................... 46 8.3 Sex ........................................................................................................................................ 47 8.4 Social Status ......................................................................................................................... 50 8.5 Summary .............................................................................................................................. 52 CHAPTER 9: FUTURE DIRECTIONS .................................................................................... 53 REFERENCES CITED ............................................................................................................... 55 APPENDIX I: ZYGAPOPHYSEAL FACET SCORES ........................................................... 65 APPENDIX II: VERTEBRAL BODY SCORES ...................................................................... 67 APPENDIX III: SKELETAL SAMPLE INDIVIDUALS ........................................................ 69 APPENDIX IV: DATA COLLECTION FORM....................................................................... 71 iv LIST OF FIGURES Figure 3.1. Drawing of normal and osteoarthritic knee ................................................................. 10 Figure 4.1. Drawing of typical thoracic vertebra ........................................................................... 18 Figure 4.2. Various ligaments of the thoracic vertebrae ................................................................ 19 Figure 4.3. Uncovertebral joint ...................................................................................................... 19 Figure 4.4. Intervertebral disc fissure ............................................................................................ 20 Figure 5.1. Regional map of Peruvian north coast with Moche sites............................................. 25 Figure 5.2. Drawing of typical thoracic vertebra ........................................................................... 26 Figure 5.3. Moche ceramic sequence and chronology ................................................................... 27 Figure 5.4. Expansion stages in the Jequetepeque Valley ............................................................. 28 Figure 5.5. Moche social pyramid ................................................................................................. 29 Figure 5.6. Drawing of boot tomb in cross-section........................................................................ 30 Figure 5.7. Drawing of Sacrifice Ceremony scene ........................................................................ 31 Figure 6.1. Sample size categoriezed by age, sex and burial type ................................................. 34 Figure 6.2. Map of excavation units at SJM .................................................................................. 35 Figure 6.3. Visual scale of zygapophyseal facet severity .............................................................. 36 Figure 6.4. Visual scale of vertebral body severity ........................................................................ 37 Figure 7.1. Thoracic nueral arch and lumbar vertebral body ......................................................... 40 Figure 7.2. Zygapophyseal facet severity frequencies by age ....................................................... 40 Figure 7.3. Zygapophyseal facet severity frequencies by sex ........................................................ 41 Figure 7.4. Zygapophyseal facet severity frequencies by burial type ............................................ 41 Figure 7.5. Vertebral body severity frequencies by age................................................................. 42 Figure 7.6. Vertebral body severity frequencies by sex ................................................................. 43 Figure 7.7. Vertebral body severity frequencies by burial type ..................................................... 43 Figure 8.1. Ceramicist recreates Moche ceramic vessel ................................................................ 46 v Figure 8.2. Drawing of naked-bound prisoners in procession ....................................................... 48 Figure 8.3. Modern Andean weaving and preserved prehistoric textile ........................................ 49 Figure 8.4. Various Moche ceramic vessels .................................................................................. 50 Figure 8.5. Woman wedging clay on floor .................................................................................... 51 Figure 8.6. Moche headdresses made of gilded copper ................................................................. 51 vi LIST OF TABLES Table 6.1. Operational definition of osteoarthritis ......................................................................... 38 Table 7.1. Chi-square and significance values for zygapophyseal facets and age ......................... 40 Table 7.2. Chi-square and significance values for zygapophyseal facets and sex ......................... 41 Table 7.3. Chi-square and significance values for zygapophyseal facets and burial type ............. 42 Table 7.4. Chi-square and significance values for vertebral bodies and age ................................. 42 Table 7.5. Chi-square and significance values for vertebral bodies and sex ................................. 43 Table 7.6. Chi-square and significance values for vertebral bodies and burial type ...................... 43 Table 7.7. Summary of Chi-square and significance values .......................................................... 44 vii CHAPTER 1. INTRODUCTION 1.1 Introduction This study focuses on prehistoric demographic differentiation at the Moche site of San Jose de Moro, Peru, as revealed by the severity of spinal degenerative joint disease (SDJD) (also referred to as osteoarthritis (OA) interchangeably throughout this text). SDJD has been used in similar studies as a gauge of prehistoric health (e.g. Sandness & Reinhard, 1992; Stirland & Waldron, 1997; Hukuda et al., 2000; Rojas-Sepulveda et al., 2008). Here it is used as a non-specific measure of the quality of life an individual had endured. Through comparisons between age classes, sexes and social classes, this study contributes to the growing body of knowledge regarding Moche social stratification. The entirety of this thesis can be subdivided into two sections: the first covers the background research necessary for this type of study (Chapters 2 to 5), and the second details the actual collection, analysis and interpretation of data, and directions for the future (Chapters 6-9). The dataset was collected and recorded with the support of the San Jose de Moro Archaeology Project over the summer field season of 2013. Actual skeletal material originated from several field seasons as far back as 1995. Despite the rich mortuary resources available from this site, intensive osteological research has been scarce. This study presents the first attempt at utilizing the San Jose de Moro skeletal assemblage with a paleopathological focus on spinal degenerative joint disease. 1.2 Statement of the Problem Social stratification has traditionally been inferred in Moche studies from the unequal treatment and preparation of graves (Chapdelaine, 2011). This implies that individual members of Moche society were not treated equally in their everyday lives, and that some form of division of labour was in place. This implication has not been verified osteologically. If no such stratification exists, and men and women of all ages equally shared in the maintenance of society, then we can expect no observable significant differences in the patterns of OA severity other than what is expected from clinical data (e.g. increasing severity with age). However, if such a stratified system was in place, then we can expect to see varying patterns of OA lesion severity between age, sex and social classes. The purpose of this research is to explore the possibility of using spinal osteoarthritis severity as a proxy and relative measure for the differences in the quality of life the Moche people endured. This is accomplished through the examination of 67 individual vertebral columns from the skeletal population at San Jose de Moro, a Moche cemetery site in the Jequetepeque Valley. By analyzing spines from different demographic sectors of this population (age, sex and social class), the hypothesis that differential OA severity occurs in this population due to social stratification is tested. 1 1.3 Thesis Outline In Chapter 2, the theoretical backdrop for the analysis and interpretation of human skeletal remains is discussed, drawing mainly from the work of Wood, Milner, Harpending and Weiss (1992). The Osteological Paradox questions the plausibility of health interpretations from skeletal lesions and age-at-death distributions (Wood et al., 1992). Specifically, osteoarthritis is evaluated in light of the issues put forth by Wood and colleagues (1992). In order to properly interpret the disease in archaeological settings, an in-depth review of human joint biology and osteoarthritis is considered with respect to both clinical and anthropological literature in Chapter 3. OA aetiology, progression, and diagnosis are covered, as well as some limitations to archaeological studies involving OA. Because this research focuses on the degeneration of the vertebral column, SDJD is highlighted in Chapter 4 through an examination of spinal joint anatomy and functionality. The degeneration of the spine is elaborated, and its differential diagnosis is discussed with respect to the limitations of such a study. OA (SDJD) is then given utility as a measure of quality of life of the Moche people. Chapter 5 strengthens the preceding chapter through an overview of Moche archaeology with a focus on the archaeological context of San Jose de Moro in the Jequetepeque Valley. The cultural entity known as the Moche, or Mochica, is described primarily concerning the archaeological and iconographic evidence. Emphasis is given to sociopolitical organization and funerary practice, as these are essential in associating burial context to specific demographic sectors of the community. Chapter 6 concerns the actual materials that comprise the data set of this analysis. This is comprised of 67 skeletons that were excavated at San Jose de Moro during the summer field seasons from 1995 to 2013. The methodological approach is also provided, which outlines the various steps and decisions that were taken through the course of data collection. Following a description of these materials and methods, Chapter 7 provides the results and analyses. In Chapter 8, a discussion and interpretation of the results is given. These are built around a dual framework that combines the paleopathological evidence with the available archaeological record. This is also where several conclusions are made about the significance and meaning of the data. Chapter 9 brings to light several issues that were encountered throughout the research process, and how these may be remedied in the future. 2 CHAPTER 2. ON THE INTERPRETATION OF SKELETAL LESIONS 2.1 Introduction The discipline of paleopathology has grown beyond single case descriptions of skeletal lesions to a more population-scale analysis of diseases in past human cultures (Wood et al., 1992; Larsen, 2002; Wright & Yoder, 2003). Because the human skeleton can retain physical memories of past events and provide a wealth of information on the lifeways of people, it serves as the prime evidence for archaeologists looking to understand the past. In this respect, bioarchaeologists and paleopathologists are responsible for analyzing skeletal deviations from the norm, and linking these observations to workable interpretations. Lesions on the human skeleton have been used to infer physical activities and behaviour (e.g. Bridges, 1992; Molleson, 2007), disease, nutrition, and health (e.g. Suby & Guichon, 2009; Liebe-Harkort, 2010; Novak et al., 2012), diet and subsistence (e.g. Corruccini1983; Mays & Beavan, 2012), violence and traumatic events (e.g. Verano, 2001; Lessa, 2004), and much more (see Larsen, 2002, for a representative overview). Thus, bioarchaeology and paleopathology can be indispensable and powerful tools in furthering our understanding of the human condition. However, as with every tool, there are dangers to its use. Our interpretations must be grounded in evidence, especially in archaeology when we are dealing with the unknown past (Hodder & Hutson, 2003). In recent decades, the intuitive approach to understanding past health from skeletal samples has been questioned (i.e. Wood et al., 1992), as well as the methods by which the assemblages under study are measured (i.e. Bocquet-Appel & Masset, 1982). Specifically, Wood et al.’s (1992) call to a reevaluation of traditional views sparked a flurry of subsequent papers debating the future of paleopathology. Their paper eloquently synthesized the various problems that had already been circulating throughout the paleopathological community (e.g. Buikstra & Konigsberg, 1985; Ortner, 1985, pers. comm., cited in Eisenberg, 1992; Jackes, 1992), namely issues with selective mortality and hidden heterogeneity in risks (Wood et al., 1992). What has been termed the “Osteological Paradox” by James Wood and colleagues (1992) can be defined as a suite of interpretations that disputes the representativeness of skeletal assemblages as reflections of health in a once-living population. Others have argued that the validity of such paradoxes is misplaced and viewed out of context (Goodman, 1993; Cohen, 1994). Both factions, however, agree that an in-depth understanding of the pathogenesis of the disease under question can greatly illuminate the debate. Here, the manifestation of osteoarthritis and its viability as an indicator of past human health are considered in terms of the three main issues of the Osteological Paradox. 2.2 The Osteological Paradox Conventional and instinctive approaches suggest a direct relationship between measures of past health and an individual’s risk of death or disease (critiqued in Buikstra & Konigsberg, 1985; Horowitz et al., 1988; Milner et al., 1989; Wood et al., 1992, Goodman, 1993; Cohen, 1994). For instance, skeletons with more lesions are likely interpreted as sicker or frailer, while those with few to no lesions would be described as healthier members of the group. However, a paradox may arise in antithetic scenarios. As Wood and colleagues (1992: 343) put it, “most interpretations of 3 paleodemographic and paleopathological data presuppose that such straightforward relationships exist.” The underlying basis for a paradox is that inferences about the living are being made from the dead. The authors raise three important conceptual problems brought about by the expansion of paleopathology and paleodemography as disciplines of active research – demographic nonstationarity, selective mortality, and hidden heterogeneity in risks (Wood et al., 1992). Demographic nonstationarity refers to the nature of populations to deviate from fixed states. Populations are never completely isolated from migration, or immune to changes in growth rates. In reality, populations fluctuate frequently and constantly in fertility and mortality rates, and age and sex distributions. When observing age-at-death distributions, the skeletal ages of dead individuals are observed. A temptation to infer mortality curves from this data may result. On the contrary, it has been shown that changes in the fertility of a population strongly affect the age-at-death distribution (Wood et al., 1992; Jackes, 1993). Thus, age-at-death statistics represent fertility measures rather than mortality measures (Wood et al., 1992). Although this problem has key importance in paleodemography, and is dealt with by Mary Jackes (1992) and others, it is not widely expounded on in Wood et al.’s (1992) paper. Rather, they focus on selective mortality and hidden heterogeneity in risks, as these are even more pertinent to understanding the representation of a disease in a cemetery population. Selective mortality states that the sample is only indicative of those who suffered and died at that age, but not of all individuals at that age. It only selects for the risks represented in those that died of that age group and not the distribution of risks experienced by all individuals involved in that age group. The population at risk cannot be determined from a skeletal sample. A sample does not represent the risk of death for those individuals who had lived past the age in question. Consequently, any skeletal sample can be considered unrepresentative of the once-living population at risk of death (Wood et al., 1992). Selectivity biases may overestimate condition prevalence by providing an observer with only those individuals that had actually died at that age, while low sensitivity to actually develop skeletal lesions from chronic illnesses may underestimate condition prevalence (Wood et al., 1992). This interplay between overestimation and underestimation may never be resolved because of the obvious lack of data from the living population. Hidden heterogeneity in risks refers to the unknown differences among individuals in a population in their susceptibility (i.e. frailty) to death. These could be due to differences in genetics, socioeconomic status, microenvironmental exposure, temporal health trends, or any variation of these (Wood et al., 1992). The nature of archaeological research does not make us privy to the level of risk exposure experienced by an individual in the past, at least not to the level of accuracy we would require for analysis of living populations. It is also very difficult to establish significant relationships between aggregate-level estimations of health and affected individuals when such heterogeneity exists. As such, several subgroups presenting different levels of risk may exist, but remain undetected when observed through skeletal assemblages. Furthermore, the likelihood of developing a skeletal lesion from a disease muddles the investigation. A high prevalence of lesions could intuitively be read as a sign of increased disease, but could paradoxically be interpreted as a sign of better health. Often, the skeleton is the last region of the body to be attacked by a disease, and even then, only a portion of people will manifest an observable bony response. The presence of advanced lesions could paradoxically indicate survival, or at least increased resistance, against a disease because the individual lived long enough through it to mount a bony response. Bioarchaeologists are 4 also primarily concerned with the skeletal markers of stress and its relationship to activity and health. The paradox questions whether higher scores for stress markers reflect increased stress experienced by an individual, or an increased ability to endure stress (Jackes, 1993). Furthermore, inherent in these observations is the assumption that the lesions observed are directly connected to cause of death. This is not often the case. The paradoxes just described can very likely be the root of misinterpretation of osteological evidence (Wood et al., 1992). It is here that knowledge of both the biology of a disease and the archaeological context in which the remains are found become essential. 2.3 Responses to the Osteological Paradox Based on the initial comments (e.g. Katzenberg, 1992; McGrath, 1992; Roth, 1992), Wood et al.’s (1992) criticism was well received. Scholars believed that the problems raised were significant and a step forward. However, the subsequent years following its publication in 1992 produced several responses. A notable contender was Mark Nathan Cohen, who argued that cemetery collections were, at least on average, representative of the once-living populations (Cohen, 1994). He asserted that this assumption was valid and allowed paleopathologists to link changes observed among the dead as reflections of real changes that had once occurred among the living. In particular, his reply is targeted towards Wood and colleagues’ (1992) interpretation of improved health following the global shift to agriculture, contrary to the interpretation of Cohen and Armelagos (1984). Wood et al. (1992) reason that agriculture fostered better nourished, healthier individuals, more able to survive and thus develop skeletal lesions in times of disease, versus relatively lesionfree hunter-gatherers and foragers. Cohen (1994) argues that several lines of evidence support his and Armelagos’s interpretation. Ethnographic and contemporary epidemiological data would suggest an increase in disease prevalence with increased population sizes and sedentism. Moreover, optimal foraging theory advocates hunter-gatherers were at a better nutritional advantage. Cohen (1994) also turns to the higher incidence of dental caries in farmers, and arthritis in hunter-gatherers. He retorts whether hunter-gatherers had died from carious infections “before their teeth had had the chance to develop lesions while farmers lived long enough to develop caries,” or whether hunter-gatherers lived long enough to allow arthritic lesions the chance to form versus their farming counterparts that died before arthritis could manifest (Cohen, 1994: 631). A sample can also be considered representative since not all deaths are caused by the pathology in question or only by that pathology alone. The random component involved in selecting those who die creates a reasonably representative sample (Cohen 1994). This is a surprising statement, and may be further refined to include both stochastic and deterministic components to mortality. The existence of pooled risk groups demonstrates that nonstochastic mortality still plays a major role in shaping life tables (Wood & Milner, 1994). Additionally, the representativeness of a certain handful of diseased individuals of the health status of an entire population is questionable. Another key response to the Osteological Paradox is Alan Goodman’s (1993) critique, stating that Wood et al.’s (1992) paradox exists only because of their narrowed focus of one, instead of multiple indicators of health. The Paradox oversimplification forgets to consider that most indicators (e.g. activity-induced lesions, enamel hypoplasias, porotic hyperostosis) imply survival of the individual after the morbidity event (Goodman, 1993). According to Goodman (1993), examination of multiple gauges of health is the key to weeding out paradoxical interpretations. Wood et al. (1992) seem preoccupied with causes of death, when in fact the goals of paleoepidemiology are to measure 5 the effects of disease, even ones with no real mortality threat, on a population (e.g. affected workloads, reproduction, and cultural and social changes) (Goodman 1993). Furthermore, Wood et al.’s (1992) analysis fails to include the important role of cultural practices in reconstructing past events. Apart from the move of paleopathology to more population-based research, the discipline has also advanced by using a multi-indicator approach in detecting prehistoric health. Consequently, researchers cannot become complacent with investigating only a single indicator, but must expand their scope either by further personal work or by the inclusion of parallel works of others. Models have also been put forth to contextualize these health and stress indicators (Goodman, 1993; Wright & Yoder, 2003), and the study of human remains has grown to include multiple fields of study to enhance our understanding of the cultural contexts and biological processes that lead to lesion development (Wright & Yoder, 2003). A decade after Wood et al.’s publication, Wright and Yoder (2003) sought to bring the bioarchaeological community back to the issues raised and update its significance. Studies are limited by the samples found, and consequently limit population-based studies as well. Our analyses of the past are then dependent on the representativeness of skeletal samples and our discerning interpretations of multiple alternative hypotheses. Wright and Yoder (2003) review five areas where bioarchaeology has grown to fill the holes that make up the paradox. These are demography, biodistance, paleodiet, growth disruption, and paleopathology. The progress described here is the continual refinement of age and sex estimation techniques (Meindl & Russell, 1998; Jackes, 2000), and development of ancient DNA and stable isotopic technologies to help demographic, biodistance and paleodiet issues. The field of enamel growth has also been extensively expanded, and has been used reliably to study biodistance, paleodiet and growth disruptions. They suggest that histological analysis may be especially significant in addressing the paradox because it may present the amount of healing (or lack thereof) occurring at a cellular level at the time of death (Wright & Yoder, 2003). Nevertheless, macroscopic evaluation will continue to be at the forefront of paleopathology since histology and ancient DNA can be costly and destructive. The authors suggest continued focus on refining the differential diagnosis process and study of varying pathognomonic lesions in order to better understand susceptibility to infection and death (Wright & Yoder, 2003). These discussions do not even begin to consider other factors outside of disease that may bias the representativeness of a sample. These include methodologies in excavation, recovery and analysis, and survival biases of skeletons (Gordon & Buikstra, 1981Walker et al., 1988; Saunders & Hoppa, 1993; Pinhasi & Bourbou, 2008). Physical, chemical and biological agents are all at play. Differences in soil conditions (Gordon & Buikstra, 1981) and weather in separate regions can produce contemporaneous samples that have drastically different preservation quality. Even different bony elements within one skeleton are differentially affected by preservation. Fetal and infant remains are also disadvantaged in making it to analysis (Pinhasi & Bourbou, 2008). Paleopathologists must be privy to these issues, as missing or damaged skeletal elements with pathological lesions will skew the data. Paleodemographers should also be aware of the underrepresentation of subadult remains. Although infant skeletons are often better preserved than their adult counterparts in some contexts (Walker et al., 1988; Merrett, pers. comm., 2013; see Pinhasi & Bourbou, 2008 for opposing view), cultural issues may still bias the sample. It could be that burial of subadults was dictated by social norms, and subadults were buried separate from the adult cemetery. It has been shown that cemeteries often segregated burials according to age, sex, and status, for example (Andrews & Bello, 2006; Bello & Andrews, 2006). Pseudopathology, also at the 6 core of observer error, refers to the interpretation of post-mortem changes as ante-mortem pathological conditions. Just as significant are the misdiagnoses of pathological lesions. These are potential sources of error that can distort results. Pinhasi and Bourbou (2008) suggest these issues be evaluated by researchers on a “case-to-case basis” owing to the huge variation in mortuary conditions. In addition, clearly illustrated methodologies and diagnostic criteria must be established before the investigation even commences. This may include gathering knowledge of a site’s geochemical properties, climatic history, possible bioturbative agents, and previous conclusions of specific mortuary peculiarities of the culture in question. Biases and pitfalls insert themselves into every step of the research process. These biases can be grouped into two categories: 1) those uncontrolled by the observer (prehistoric cultural practices and bone survival), and 2) those controlled by the observer (search, recovery and analysis methodology) (Pinhasi & Bourbou, 2008). Investigators should be aware of these potential traps for incorrect evaluations. Such an attention to detail will describe the future course of paleopathology and paleoepidemiology, and illuminate understanding of morbidity profiles of the past. 2.4 Osteoarthritis in Light of the Osteological Paradox It is apparent that each pathology is unique in its nature, and must first be evaluated separately from the manifestations of other diseases, even when co-occurring in the same body. In reality, health is so broad a dimension that reliance on the most convenient indicator cannot be thought of as representative (Wright & Yoder, 2003). I propose that not all diseases suffer at the hands of ambiguous interpretations challenged by the Osteological Paradox, but other factors creating the mortality profile of a sample causes enough interference that even thorough investigation of one line of evidence is insufficient in the absence of other corroborating avenues. This thesis explores just one of these avenues, looking at osteoarthritis as a potential indicator of the quality of life a person had endured. It is my hope that other researchers explore questions about class structure in Moche daily life at San Jose de Moro, and whether such findings will corroborate or refute the observations and interpretations here. Osteoarthritis is not a perfect indicator of the quality of life. Although the severity of OA lesions may progress, increasing joint stress, pain, discomfort and disability may never manifest or correlate in the living individual (Birrell et al., 2005; Busija et al., 2006). Furthermore, the formation of lesions does not progress uniformly in every individual due to genetic predispositions (Rogers et al., 1997). Such factors are nearly impossible to discern in the archaeological record. These obstacles are further discussed in Chapter 3. Osteoarthritis has been used classically as an indicator of health and stress (e.g. Merbs, 1983; Bridges, 1992, 1994; Stirland & Waldron, 1997; Rojas-Sepulveda et al., 2008; Molnar et al., 2011; Novak et al., 2012). The rationale behind the use of chronic afflictions, such as arthritis, is its progression in a relatively straightforward manner (Cohen, 1994). What Wood et al. (1992) had been describing in their paper were diseases that progress through other body systems before finally affecting the skeletal system, assuming the individual survived long enough and if bony lesions developed at all. Osteoarthritis, among several other osteological diseases, can be considered a primary disease of the skeletal system, as it originates from the inevitable wear and tear of synovial joints and can directly change the morphology of bone (Brandt et al., 2006). The presence of this degenerative disease is not a major factor in deaths making its prevalence in a skeletal assemblage a relatively reliable reflection of the prevalence in the once-living population (Waldron, 1994: 101). 7 However, although it is accumulated throughout life, the levels of arthritic lesions present on a skeleton influence not only with the amount of physical stress exerted on the joints, but also are caused by sex, age and genetics. Moreover, the study of “bone formers” by Rogers and colleagues (1997) present a different view by identifying certain members of the population predisposed to growing bony lesion even in the absence of environmental stressors. Intentions of measuring the relative quality of life in a skeletal sample through the evaluation of osteoarthritic severity is not without its faults, but an attempt is still made here to open the possibility of future research from a refinement of the techniques used here as well as other investigative tools. 2.5 Summary The interpretation of skeletal lesions remains a challenging prospect. On the one hand, intuitive approaches have had success in the past (Rojas-Sepulveda et al., 2008). On the other hand, paradoxical situations may hold some validity. If one thing can be learned from this back-and-forth debate, it is that interpretations must be tailored to the sample at hand, keeping in mind the cultural context and the indicators of health in question. The biology of a disease, the mortuary activities of past peoples, and the taphonomic processes at play are all instrumental in solidifying the representativeness of skeletal assemblages. Although spinal degenerative joint disease remains the focus of this research, the proposals of Goodman’s (1993) and Wright and Yoder’s (2003) multi-indicator approach remain critical in dealing with the Osteological Paradox and building inferences of past health. With regards to osteoarthritis, it seems degenerative joint disease serves as only one indicator of stress. Nonetheless, progressively worsening lesions may not impact the living person, or his or her ability to contribute to their community (Birrell et al., 2005; Busija et al., 2006), or even reflect a mechanical response (Rogers et al., 1997). Consequently, a review of joint biology and osteoarthritis is necessary to bring to light the shortcomings and important considerations of this type of study. 8 CHAPTER 3. OSTEOARTHRITIS AND JOINT BIOLOGY 3.1 Introduction Motion in vertebrates is facilitated by the antagonistic push and pull of musculature exerted on the skeletal system. The skeleton, with its many constituent elements, provides a foothold for these muscles. In humans, the different bones of the body are articulated to one another via joints, with the exception of the hyoid or floating bone. There are many types of joints in the human body, the most common of which are synovial joints (Waldron, 2009). Different types of joints serve different functions, and the changes we observe can illuminate the biological profile of an individual. Some joints change morphology with age, and this has been used by physical anthropologists to age skeletons (e.g. changes to the auricular surface, pubic symphysis, sternal rib ends, cranial sutures, see Buikstra & Ubelaker, 1994). The degenerative changes to joints can also be accelerated by physical stressors, and have been used to infer activity and occupation (e.g. Bridges, 1992; Stirland & Waldron, 1997; Molleson, 2007; Molnar et al., 2011). The inevitable wear and tear of joints from regular use characterizes osteoarthritis (OA), also known as degenerative joint disease (DJD) (Creamer & Hochberg, 1997; White & Folkens, 2005; Waldron, 2009; Anderson & Loeser, 2010). Osteoarthritis can be described as the gradual breakdown of articular cartilage within synovial joints (Goldring & Goldring, 2007). The cartilage serves as a cushion between two bones, and when this cushion is compromised, the bones begin to grind away at each other eliciting various changes to the joint. It is the most common skeletal disease encountered worldwide by archaeologists and paleopathologists (excluding dental diseases) (Creamer & Hochberg, 1997; Weiss, 2006; Weiss & Jurmain, 2007; Molnar et al., 2011; Lotz & Loeser, 2012). Its diagnosis in skeletal samples has been used to infer handedness, and the differences between sexes, social status and populations (Bridges, 1992). Our knowledge of OA is far from complete. There is still a lot of debate surrounding OA aetiology and diagnosis, especially between anthropologists and clinicians. This section tackles the essential aspects of synovial joint biology, followed by a discussion on OA aetiology and pathogenesis, progression and diagnosis, and its relation to other diseases. 3.2 Synovial Joint Biology A joint is where any two or more bones meet (Waldron, 2009). Different types of joints vary in their mobility, and serve different functions as a result. Sutures are immobile fibrous connections that hold bones of the skull in place. Syndesmoses are fibrous joints with minor movement only permitted by the slight stretching of ligaments that hold them in place. A gomphosis fixes dentition to its respective alveolus in the oral cavity. Symphyses join bones through a fibrocartilaginous tissue. The degree of movement in a symphysis, such as the pubic symphysis or intervertebral discs, is very limited. Synchondroses are those joints temporarily formed from the hyaline cartilage model of developing bone in subadults. Synovial joints are those that contain a synovial membrane and are fully mobile. They are the most common joints in the human body, and are most commonly affected by disease (Waldron, 2009). Two joints constitute the articulations of the vertebral column, namely the symphyses between the intervertebral discs and vertebral bodies and the synovial joints between 9 zygapophyseal facets, uncovertebral joints and costovertebral joints (see section on Spinal Degenerative Joint Disease). The synovial joint can be considered as an organ because of the diverse tissue types that compose it, and as such, pathologies affecting one tissue type will have subsequent effects on adjacent parts (Archer et al., 2003). A synovial joint is composed of the bones involved, each coated by hyaline articular cartilage and held together by ligaments, synovium, and fibrous capsules (Archer et al., 2003). The synovial membrane exists to nourish chondrocytes, lubricate joint surfaces, and clean the joint of any debris or microorganisms resulting from the degeneration of the joint (Waldron, 2009). The cartilage that coats the articulating surfaces of bone is avascular and aneural, which results in a low capacity for self-repair and high susceptibility to degenerative diseases such as OA (Oldershaw, 2012). Healthy articular cartilage is very efficient in reducing the friction between bones during movement (Waldron, 2009). It does not show up on radiographs, but appears as a void space between bones, referred to by radiologists as the joint space. Directly curved beneath the cartilage is subchondral bone, usually composed of trabeculae that is covered by a thin cortex without periosteum. Synovial joints are instrumentally significant to the study of OA because OA only develops at joints that move (Waldron, 2009). 3.3 The Aetiology and Pathogenesis of Osteoarthritis Anthropologists, skeletal biologists and medical doctors unanimously agree that the cause of osteoarthritis is multifactorial, encompassing a number of precipitants and guilty agents (Busija et al., 2010; Hunter, 2011). It should be understood that no one risk factor can solely contribute to the development of OA, but a combination of these are responsible. Some risk factors such as age and obesity carry greater weight as precipitants (Anderson & Loeser, 2010; Loeser, 2011). Although OA is conventionally defined as the destruction of the articular cartilage resulting in joint failure, it is not a disease that manifests exclusively in cartilage (Brandt et al., 2006). Rather, Figure 3.1. Schematic drawing of the knee joint juxtaposing the components of a normal knee (left) and joint tissues affected in OA (right). Modified it seems many of the tissues involved from Hunter, 2011: 802. in the diarthrodial organ can be attributed to the aetiology of the disease, whether it be the subchondral bone, synovium, capsule, periarticular muscles, sensory nerve endings, meniscus (if present), or ligaments (Brandt et al., 2006) (Fig. 3.1). Ultimately, the disease 10 occurs when the equilibrium of breakdown and repair of joint tissues becomes unbalanced (Hunter, 2011). Such a situation can be elicited in two ways: 1) by intrinsic factors and by 2) extrinsic factors. Intrinsic factors are inherent to the body such as age, body mass, sex and genetic predisposition. Extrinsic factors are those forces outside the body acting on its joints. These are the mechanical loads produced from occupation and activity or traumatic events. OA is often referred to as primary when no direct cause can be attributed to its formation, but arises from the multifactorial nature of its aetiology (Creamer & Hochberg, 1997, Waldron, 2009). Not one single precipitant can be positively assigned as the proximate cause. The term secondary OA is used when a single cause can be identified such as OA following trauma or rheumatoid arthritis (Waldron, 2009). OA is a mechanically induced disease, whether initially resulting from excessive loads on normal tissues, normal loads on abnormal tissues, or a combination of the two (Brandt et al., 2006). The pathogenesis of OA can be attributed to highly varied interactions of mechanical, cellular and biochemical agents (Hunter, 2011). Age has long been accepted as a major factor in osteoarthritis development. In general, older individuals exhibit more widely dispersed, severe cases of OA than younger individuals. This would make sense since the longer a joint is in use, the more the joint will deteriorate. On the other hand, OA is ordinarily described as joint wear and tear, but OA is not simply the result of the waning uselife of a joint, but rather the disruption of healthy cellular and biochemical functions (Lotz & Loeser, 2012). Aging cartilage is not necessarily cartilage inflicted with OA (Goldring & Goldring, 2007). Several researchers agree that increasing chondrocyte senescence contributes to the development of OA (Anderson & Loeser, 2010; Loeser, 2011; Lotz & Loeser, 2012). The disruption of normal chondrocyte abilities to maintain cartilage produces increased cytokines, oxidative damage and decreased growth factors, which all stimulate cellular death (apoptosis) and matrix degradation (Goldring & Goldring, 2007; Anderson & Loeser, 2010). The turnover from muscle mass to fat mass that accompanies age has also been suggested as an explanation for OA in older individuals due to increased joint loading (Loeser, 2011). Obesity in modern times is the “single most important risk factor for development of severe OA of the knee” (Hunter, 2011: 804). The knee joint is particularly sensitive to obesity (Manek et al., 2003; Hunter et al., 2005; Hunter, 2011), but hardly affects the hip (Creamer & Hochberg, 1997), which might suggest mechanical factors are not OA’s sole contributor, but rather other factors are also important (Creamer & Hochberg, 1997). In archaeological settings, it is doubtful individuals were overweight to the same degrees observed today due to a lack of foods with high fat and sugar contents (Arriaza, 1993). The implication of obesity as a major risk factor in archaeological remains is slim. However, some scholars have attempted to equate the prevalence of diffuse idiopathic skeletal hyperostosis (DISH) to obesity and insulin-independent diabetes mellitus (Rogers & Waldron, 2001; Mays, 2006; Verlaan, et al., 2007). These studies have focused on samples from medieval monastic Europe when fatty foods were more abundant (Mays, 2006) than in preceding periods. The clinical data does affirm that chronic, heavy loads on joints are an important precipitant for OA (Weiss, 2006; Brown et al., 2008). Sex is also a predisposing risk factor, with women being generally more susceptible than men (Creamer & Hochberg, 1997; Goldring & Goldring, 2007; Hunter, 2011) with up to 50% greater likelihood of OA development (Busija et al., 2010). It has been suggested that the depletion of estrogen levels after menopause in women could explain the disparity between the sexes (Busija et 11 al., 2010), although the preliminary reviews are weak (Hanna et al., 2004). Anatomical differences may also be responsible. Hunter et al. (2005) demonstrated that women, on average, have higher knee height, which contributes to greater torque when in motion. The greater mechanical forces involved were associated with increased OA likelihood (Hunter et al., 2005). In contrast to epidemiological findings, there is a surprisingly broad variation in the manifestation of OA between males and females from archaeological contexts (Bridges, 1992). Some sites have reported greater levels of OA in males (Bridges, 1992), greater levels in females (Molnar et al., 2011), or no significant difference between the two (Waldron, 1995). Sex differences have been used by bioarchaeologists to infer gender roles in past societies (Molleson, 1994, 2007). The use of only one indicator to infer activity may be inadequate, but a plethora of indicators may still be useful if a significant pattern arises that is well documented, comparisons are drawn with other possible conditions, juxtapositions are made with an equivalent normal sample, and independent environmental or comparative evidence is reviewed (Wright & Yoder, 2003; Molleson, 2007). Probably one of the most difficult risk factors to control for in studies of osteoarthritis, whether in clinical or archaeological settings, is genetic predisposition. Anthropologists are usually interested with the effects of repetitive mechanical loading and aging on joints. However, clinical data on twin and familial studies suggest a strong genetic component, influencing OA at an estimate of 35% to 65% (Cicuttini & Spector, 1997; Fernandez-Moreno et al., 2008). Several investigations have confirmed that the genetic mechanisms involved in OA follow polygenic inheritance rather than simple Mendelian pathways (Fernandez-Moreno et al., 2008; Loughlin, 2011). It would seem that different joints have varying degrees of genetic susceptibility (Spector & MacGregor, 2004; Weiss & Jurmain, 2007). The hip and spine in particular have the highest heritability estimates at 60% and 70% respectively, while the hand and knee are at 39% to 65% (Spector & MacGregor, 2004). It is worth noting that genes may not determine the presence or absence of osteoarthritis, but affect the severity of already present OA (Weiss & Jurmain, 2007). Weiss and Jurmain (2007) urge that spinal degenerative disease is highly probably not a good indicator of activity because of its heavy reliance on the genetic component of OA. Furthermore, Rogers et al. (1997) have identified that a portion of individuals are predisposed to produce more bone than usual, termed so called bone formers. These bone formers, for example, would produce larger osteophytes versus the average person even when exposed to similar environments. The larger osteophytes would then be recorded by the paleopathologist as more severe, and potentially skew the analysis. An attempt to distinguish bone formers in skeletal assemblages failed to produce any significant results (Schmitt et al., 2007). This is not to say anthropological studies of osteoarthritis on skeletal remains are hopeless endeavors. In instances of extreme physical stress, mechanical factors may overwhelm genetic predisposition as principle aetiological agents (Manek et al., 2003; Thelin et al., 2004). Preliminary data also indicates that bone formers comprise only a small portion of the population (Rogers et al., 1997). Some of the limitations of comparative studies caused by genetic components may be reduced by limiting the sample under study to one geographical origin and incorporating a large enough sample size. Apart from the factors intrinsic to the biological makeup of the body (age, BMI, sex and genetics), physical activities influence the development of OA (Creamer & Hochberg, 1997; Hunter, 2011). Waldron (2009: 28) states, “movement is a sine qua non for the production of OA; joints that do not move, do not develop OA.” This is of prime concern to anthropologists seeking to link stress and activity to physical markers left on the bone. Molleson (2007) has attempted to create a process for the differential diagnosis of specific activities. This is a bold attempt, as many scholars caution 12 that specific activities may never be inferred because very different activities can produce similar lesions, while the same activity can manifest differently between individuals (Gualdi-Russo & Galletti, 2004; Meyer et al. 2011). Even Molleson (2007) acknowledges the limitations of estimating activity and occupation but believes a high degree of likelihood is attainable. Certainly, this has not stopped anthropologists from inferring past occupations (e.g. Bridges, 1994; Molleson, 1994; Stirland & Waldron, 1997; Molnar et al., 2011). The premise is actually quite valid if conclusions are made in broad terms. I have no doubt physical stress plays a vital role in OA aetiology, and its contributions to the development of prehistoric OA cannot be ignored. Perhaps it would be more prudent to equate higher levels of observed OA to more exposure to physical stress rather than attempting to assign specific activities. It should be pointed out that there is a poor correlation between radiographic OA severity and symptomatic disability (Birrell et al., 2005; Busija et al., 2006). Thus, greater degrees of severity observed on dry bone may not directly translate to a more impaired lifestyle. However, more severe manifestations of OA lesions may still indicate more prolonged and greater exposure to mechanical stress, controlling for age, sex and possibly genetics. 3.4 The Progression and Diagnosis of Osteoarthritis Several morphological changes occur to the articulating bones as osteoarthritis progresses. These are what paleopathologists observe and score in postmortem remains. Following Wolff’s Law, bone will adapt to the mechanical loads acting on it in order to compensate the stress. In joints afflicted with OA, new bone will begin to form at the joint margins. These are what are referred to as marginal osteophytes and are observable on radiographs. It has been suggested that their development expands the articular surface as a way of compensating for the failing joint (Van der Kraan & Van den Berg, 2007). New bone will also form on the subchondral bone because of joint surface vascularisation (Rothschild, 1997; Waldron, 2009). These are observable on x-rays as areas of sclerotic subchondral bone (Creamer & Hochberg, 1997). The joint surface may in turn exhibit porous lesions that may or may not extend directly into the underlying trabeculae and unite with subchondral cysts. Rothschild’s (1997) review of clinical literature has questioned the significance of porosity in diagnosing OA, asserting that porosity’s clinical significance can only be assumed, as it is not readily observable during life, unrecognizable on x-ray, and does not appear in standard medical literature. Because it is unseen in radiographs, it is often excluded from a clinician’s differential diagnosis. The physical anthropologist, however, is privy to the macroscopic observation of pitted joint surfaces on dry bone. Porosity has been used diligently by paleopathologists as an indicator of osteoarthritis (e.g. Bridges, 1992, 1993; Buikstra & Ubelaker, 1994; Weiss & Jurmain, 2007). It is difficult to digest Rothschild’s (1997) contention when porosity and eburnation are so often encountered simultaneously in both archaeological and contemporary skeletal material. Its absence in the medical literature may be due to the nature of the specimens clinicians and anthropologists analyze, and the techniques by which they are analyzed. Canines subjected to anterior cruciate ligament transections developed OA, and demonstrated osteopenic subchondral trabeculae (Dedrick et al., 1997). In mice injected with collagenase to induce instability-related OA, pitting and thinning of the subchondral bone plate resulted from increased osteoclastic resorption directly beneath the subchondral bone plate (Botter et al., 2011). It should be 13 noted that four weeks after the experiment, the perforations disappeared due to increased osteoblastic activity in the subchondral bone trabeculae (Botter et al., 2011). Nevertheless, these preliminary animal models may provide insight into the aetiology of joint surface porosity in osteoarthritis. Eventually, the joint contour will progress to a flatter and wider appearance than what is normal. If allowed to develop into its advanced stages, eburnation will follow. Eburnation is the result of bare bone rubbing on bare bone, and represents the ultimate destruction of cartilage, creating polished areas on the joint surface. Many researchers consider it pathognominic of OA (Rothschild, 1997; Weiss & Jurmain, 2007), and some have used it as the sole criterion for diagnosing OA in the skeleton, fearing the ambiguity of other indicators (e.g. Rojas-Sepulveda, 2008; Molnar et al., 2011). This is faulty however, since eburnated bone illustrates OA in its most advanced stages (Rothschild, 1997). Thus, limiting a study to only eburnation will undoubtedly miss those bony elements or whole individuals afflicted with early and intermediate stages of the disease. The diagnosis of osteoarthritis between clinicians in the living and paleopathologists in the dead varies considerably. This is in obvious part due to the differences in the viewing methods of suspected joints. In a live patient, diagnosis is often conducted through palpation. If a joint is affected by OA, it will be swollen and enlarged. Pain and crackling sensations may also accompany the joint (Creamer & Hochberg, 1997). Radiologists refer to joint space narrowing, marginal osteophytosis and sclerotic subchondral regions for a diagnosis (Creamer & Hochberg, 1997; Rothschild, 1997; Spector & MacGregor, 2004). The paleopathologist on the other hand can add to this list by including pitting on the joint surface and alteration of the joint contour. Pitting and contour are much better observed through gross inspection of the bone rather than radiographs or palpation. From this information, I will adopt Waldron’s (2009) operational definition of osteoarthritis. A joint can be highly suspect of exhibiting osteoarthritis if eburnation is present, or if at least two of the following are present: marginal osteophytosis, new bone on the joint surface, pitting on the joint surface, and alteration in joint contour (Waldron, 2009). If only one of the latter criteria is present, diagnosis of OA is dubious, as it has been observed that isolated indicators can occur independent of the disease (van der Kraan & van den Berg, 2007). 3.5 Osteoarthritis and Other Diseases Osteoarthritis is the most common joint disease. As such, it often results in association or as a complication of other diseases (Waldron, 2009), not all of which can be discussed fully here. The following are some examples that are pertinent to the examination of osteoarthritis in archaeological remains: Paget’s disease of bone, calcium pyrophosphate deposition disease, and intervertebral disc disease. Paget’s disease of bone (PDB) is characterized by accelerated production of remodeled bone, with hyperactivity of osteoblastic and osteoclastic functions (Cundy & Reid, 2012; Ralston & Layfield, 2012). Clinical studies have shown a high association between PDB and secondary OA (Ralston, 2008; Cundy & Reid, 2012). PDB when focused on joint margins may actually accelerate the course of OA in the affected joint (Helliwell, 1995). This association is likely due to the alteration of normal cellular and metabolic activity in the joint dynamics (Ralston, 2008). PDB is a 14 rare disease and its diagnosis in archaeological assemblages is difficult and uncommon (Waldron, 2009). Calcium pyrophosphate deposition disease (CPDD) is sometimes misclassified as osteoarthritis (Rothschild, 1997). In this arthropathy, calcium pyrophosphate dihydrate (CPP) crystals are deposited in tissues, most commonly fibrocartilage and hyaline cartilage, and may ossify as spicules (Ferrone et al., 2011). It is still unclear whether the deposition of crystals contributes to the pathogenesis of OA, or if the crystals are a result of the joint degeneration (Ferrone et al., 2011). CPDD has been distinguished from OA in a skeletal collection by a reflective calcified sheet on the articular surface (Rothschild, 1997). Some of the changes observed in osteoarthritis also occur on vertebral bodies afflicted with intervertebral disc disease (IVD). The intervertebral discs situated between the vertebral bodies of the spine act as cushions that allow mobility and weight absorption. In IVD, the disc will tend to bulge outward and collapse because of the normal aging process (Waldron, 2009). Marginal osteophytes may develop around the vertebral body rim both superiorly and inferiorly, accompanied by pitting of the vertebral body surfaces (Prescher, 1998). These symptoms most commonly occur in the cervical and lumbar regions, areas of maximum curvature and shock absorption (Bridges, 1994). It is important to note that osteophytes are not exclusive indicators of OA, but may develop in a multitude of situations such as IVD. Spinal degenerative joint disease is evaluated in relation to both IVD of the vertebral bodies and OA of the synovial portions of vertebrae (see section on Spinal Degenerative Joint Disease). 3.6 Summary The understanding of osteoarthritis is far from complete. What is certain is that the pathogenesis of OA is multifactorial, involving mechanical, cellular and biochemical agents. Age, genetics and obesity are strong risk factors for the development of OA, although the latter is of little concern in prehistoric populations. Genetics may be difficult, if not impossible, to control in archaeological studies, but by limiting the sample to one geographical region and collecting a large enough data set, the influence of this variable in comparisons may be reduced. By focusing on the mechanical contributions to OA aggravation, anthropologists can make more grounded inferences of past human activities. Eburnation is considered pathognomonic of osteoarthritis (Rothschild, 1997; Weiss & Jurmain, 2007). In its absence, the presence of two of the following indicators strongly suggests OA of a joint: marginal osteophytosis, new bone on the joint surface, pitting on the joint surface, and alteration in joint contour (Waldron, 2009). OA can result as a complication of other diseases or trauma. Its most probable differential diagnosis in archaeological remains is integral to the quality of conclusions drawn from studies. Despite the limitations discussed above, the paleopathological study of OA can provide archaeologists a wealth of information on gender roles, occupational stress, and social status differentiation. The need for further study of OA past and present is warranted. Because OA is diffuse throughout the joints of the body, a specific anatomical region may be observed for lesions indicative of OA. The region of concern here is the vertebral column. As is 15 demonstrated in the following section, spinal degenerative joint disease (or spinal OA) is attributed to the factors described above with the inclusion of axial load bearing (Sandness & Reinhard, 1992; Lotz & Loeser, 2012; Novak et al., 2012). Its utility in assessing quality of life must be evaluated with respect to spinal anatomy and biomechanics, as well as the qualities of spinal degeneration. 16 CHAPTER 4. SPINAL DEGENERATIVE JOINT DISEASE 4.1 Introduction The spine is an important load bearing structure in the body (Fujiwara et al., 2000; Niosi & Oxland, 2004; Laplante & DePalma, 2012). It serves to protect the delicate spinal cord and restrict movement of the thorax for proper bipedal locomotion (Bridges, 1994; Niosi & Oxland, 2004; Laplante & DePalma, 2012). Majority of the weight from the upper body is supported by the natural curvature of the spine acting as a spring and maintaining the necessary center of gravity for balance (Platzer, 2004). This is in addition to the cushioning effects of the intervertebral discs (Prescher, 1998; Ustundag, 2009). Several degenerative changes occur to the bony and cartilaginous structure as a consequence of age, sex, strenuous activity and other factors. Its role in weight bearing is also a strong contributing factor (Laplante & DePalma, 2012). A common theme in bioarchaeological research is the estimation of health, physical stress exposure, and quality of life from skeletal remains (Faccia & Williams, 2008). Physical anthropologists have used the bony changes in the spine in an attempt to assess these factors (Sandness & Reinhard, 1992; Stirland & Waldron, 1997; Hukuda et al., 2000; Rojas-Sepulveda et al., 2008). The findings are often cited in more thematic explorations of prehistoric social stratification, subsistence strategies, political organization, gender roles and other such macroscopic aims. As stated above, increased physical stress and load bearing of the spine can aggravate its degeneration. This makes the spine particularly useful for these kinds of endeavors (Sandness & Reinhard, 1992). This paper explores pertinent aspects of spinal anatomy, degenerative changes of its constituent parts, osteological criteria for the diagnosis of spinal degenerative joint disease, and the limitations of the spine in archaeological inquiries. The objective is to consider spinal degenerative joint disease and its role in bioarchaeology. 4.2 Anatomy of the Spine The human vertebral column consists of seven cervical, twelve thoracic, and five lumbar vertebrae. Five additional fused sacral elements follow the fifth lumbar. Individual vertebral elements increase in size caudally with a narrowing of the neural arch foramina. Some discussions also include the three to four fused coccygeal vertebrae, which are rudimentary elements that follow the sacrum. Most investigations into spinal arthropathies only include the cervical, thoracic and lumbar vertebrae (Sandness & Reinhard, 1992; Hukuda et al., 2000), and may sometimes include the superior face of the first sacral segment (Papadakis et al., 2010; Novak & Slaus, 2011; Burke, 2012). The typical vertebra is comprised of two main parts: the body and the neural arch (Fig. 4.1). The vertebral body extends posteriorly into the anterior portion of the neural arch, the pedicles. The pedicles continue to arch posteriorly, now called the laminae, and join from left and right sides to form the spinous process. At the junction where the pedicles and laminae meet are laterally extending transverse processes. Also at this junction are two sets of articular facets, one superior set and one inferior set. These are called zygapophyseal facets, apophyseal facets, or simply articular facets, which accommodate the inferior facets of the vertebral element above and affix into the superior 17 facets of the vertebra below. Between each of the vertebral bodies, apart from the articulation between the atlas and axis, is an intervertebral disc which acts as a gelatinous-like padding. The entire tower-like column is held in place by a series of ligaments. Thoracic vertebral bodies possess laterally placed facets for the rib heads, and facets on the transverse processes for the costal tubercles. The typical curvature of the adult spine in sagittal view is characterized by an S-shape, with cervical lordosis, upper thoracic kyphosis, lower thoracic and lumbar lordosis, and sacral kyphosis. The curvatures are well marked much after infancy because of the erect postures involved in sitting and standing throughout life (Platzer, 2004). Flexion, extension and lateral flexion occur Figure 4.2. Various features of a typical thoracic vertebra. Superior primarily in the cervical and lumbar spines, view, anterior is up (left). Lateral view, anterior is left, superior is while rotation is mainly possible through the up (right). Modified from Netter, 2006: Plate 154. thoracic and cervical regions. Regions of greater mobility are more subject to damage and injury from mechanical overloading (Platzer, 2004). The intervertebral discs each comprise of an outer layer called the anulus fibrosus and an inner nucleus called the nucleus pulposus. The anulus fibrosus is made up of concentrically arranged fibrocartilagenous and collagen fibers held in strong tension. It encapsulates the viscous nucleus pulposus, which primarily serves as a shock absorber (Prescher, 1998; Ustundag, 2009). The entire disc is held firmly in place by Sharpey’s fibers, which insert at the margins of the vertebral bodies (Waldron, 2009), and acts as a ligament holding the vertebral bodies together and allowing slight movement. Unilateral stretching or compression is involved when the spine is in motion. The deterioration of the intervertebral discs has been proposed as the primary cause for the degeneration of the vertebrae (Prescher, 1998). Studies have shown that disc degeneration generally precedes arthritic facet changes (Niosi & Oxland, 2004). The various ligaments of the vertebral column are put in place to support and strengthen the vertebral articulations (Fig 4.2). They also serve to facilitate the proper movement of the spine. The anterior longitudinal ligament runs down anterior to the vertebral bodies, beginning at the anterior tubercle of the atlas and ending at the sacrum. It expands caudally, and affixes firmly onto the vertebral bodies, but only loosely overlaps the Figure 4.3. (1) Anterior longitudinal ligament, (5) ligamenta flava, (7) intertransverse ligaments, (8) interspinous ligaments, (9) spinal processes, (10) supraspinous ligaments, (12) superior and (13) lateral costotransverse ligaments, (14) radiate ligament of the rib head. Modified from Platzer, 2004: 57. 18 intervertebral discs (Platzer, 2004). Long and short perivertebral bands parallel to the lateral sides of the anterior longitudinal ligament link adjacent intervertebral discs. Opposite the anterior aspect of the vertebral bodies is the posterior longitudinal ligament, which runs down the posterior vertebral bodies. Unlike its anterior counterpart, the posterior longitudinal ligament narrows as it approaches the sacrum from the atlas. In the thoracic and lumbar regions, this ligament expands at the intervertebral discs and attaches to the discs and superior vertebral rims (Platzer, 2004). The two longitudinal ligaments serve to stabilize movement during flexion and extension, and protect the intervertebral discs (Platzer, 2004). The ligamenta flava attach between the neural arches of the vertebrae surrounding the vertebral foramen. They are held in constant tension and help return the spine to an erect position after flexion (Platzer, 2004). Short intertransverse ligaments and interspinous ligaments attach between the transverse processes and spinous processes of adjacent vertebrae, respectively. The supraspinous ligaments originate at the tip of the seventh cervical vertebra and continue downward to the sacrum, attaching at the subsequent spinous processes. The ligamentum nuchae attaches from the external occipital crest to the cervical spinous processes. Costal elements are held in place on thoracic vertebrae by the superior costotransverse ligaments, lateral costotransverse ligaments and radiate ligaments of the rib heads (Platzer, 2004). At each of these ligament attachments there is the potential for osteophyte formation (Hukuda et al., 2000). Although there are only two types of joints involved in the spine (symphyseal and synovial), there are many points of articulation involved between vertebrae, and between the thoracic vertebrae and ribs. The first type can be found at the intervertebral discs, which are each sandwiched between two hyaline cartilage plates. The intervertebral symphysis, together with the longitudinal ligaments, allows some movement. The second type is synovial joints found between the zygapophyseal facets, uncovertebral joints, atlanto-occipital joint, atlanto-axial joint, lumbosacral joint, and costovertebral joints. Tension levels in these areas increase caudally. Zygapophyseal joints in the cervical vertebrae contain meniscoid folds, which allow greater load bearing amidst more lax articulations relative to the thoracic and lumbar regions (Platzer, 2004). Despite being synovial joints, movement is only slight. The collective movement of consecutive zygapophyseal joints and intervertebral symphyses results in greater mobility of the thorax. Specific to the cervical vertebrae, the uncovertebral joints or Luschka’s joints are formed between the uncinate processes at the superior posterolateral rims of the cervical bodies articulating with the inferior cervical bodies above (Hayashi & Yabuki, 1985) (Fig. 4.3). The joint space of the uncovertebral joint begins to extend slightly into the intervertebral disc at the age of nine or ten, but may eventually extend across the entirety of the disc causing pulposus herniation (Platzer, 2004) (Fig. 4.4). The atlas laxly articulates superiorly with the occipital condyles, and inferiorly with the articular facets and dens of the axis. The slack and incongruent articulations provide greater movement of the skull. The Figure 4.4. Uncovertebral joint between the lumbosacral joint involves the synovial articulation between C6 and C7 (top). Uncovertebral joint the fifth lumbar and first sacral segment. In some cases, the enlarged (bottom). Anterior view. Modified lumbar vertebrae will variably fuse to the sacrum (Konin & from Platzer, 2004: 59. Walz, 2010). Ribs are also joined to thoracic vertebrae through 19 costovertebral synovial joints. Aside from the first, eleventh and twelfth ribs, rib heads articulate partly on the upper and lower margins of adjacent vertebrae. The costal tubercle articulates with the transverse process of the thoracic vertebra via a synovial joint, except in the eleventh and twelfth ribs where costotransverse joints do not typically exist. The mobility of the rib cage partly owing to the costovertebral joints is required for respiration (Platzer, 2004). A thorough understanding of vertebral anatomy is a prerequisite for the appreciation of degenerative changes afflicting the spine. 4.3 Degeneration of the Spine Spondyloarthropathies, or pathologies of the spinal joints, target the different points of articulation just described. These changes are typically associated with normal aging, but sex, body mass, genetic predisposition, previous trauma and physical activities are all intricately involved (Prescher, 1998; Weiss & Jurmain, 2007; Pouletaut et al., 2010; Zukowski et al., 2012; see section on the Aetiology and Pathogenesis of Osteoarthritis). The nucleus pulposus gradually becomes more fibrous with age, losing internal pressure, viscosity and height, and shrinks. As a result, the tension of the annulus fibrosus decreases and the fibrocartilage and collagen fibers tear (Prescher, 1998; Niosi & Oxland, 2004; Platzer, 2004; SarziPuttini et al., 2004). This results in a more crumbled, solid-like disc and an annulus fibrosus with multiple clefts and fissures (Niosi & Oxland, 2004; Wilmink, 2011). Blood vessels may Figure 4.5. Fissure across the intervertebral disc originating from the uncovertebral penetrate the failing disc and consequently initiate ossification joint space. Anterior view. Modified from (Prescher, 1998). The disc loses its ability to distribute and Platzer, 2004: 59. absorb loads through compression and expansion (Sarzi-Puttini et al., 2004). This can cause several secondary effects on the osseous and cartilaginous elements of the intervertebral symphysis such as changes to the body surface contour, osteophytosis of the vertebral rim, vertebral body sclerosis, and ossification of associated ligaments (Lipson et al., 1985; Prescher, 1998; Niosi & Oxland, 2004; Watanabe & Terazawa, 2006). In some cases, osteophytes from adjacent vertebral bodies will contact each other and kiss, coalesce or completely fuse (Maat et al., 1995; Sarzi-Puttini et al., 2004). Afflicted uncovertebral joints are characterized by osteophytes on the uncinate processes (Sarzi-Puttini et al., 2004). Occasionally, osteophytes originating from the body and uncinate process may protrude into the intervertebral foramina and can cause compression of the nerve roots and vertebral artery, particularly in the cervical spine (Prescher, 1998; Waldron, 2009). Histological inspection of degenerated intervertebral discs shows comingled fragments of hyaline cartilage, fibrocartilage, nucleus pulposus, and acute and chronic inflammatory cells (Lipson et al., 1985), indicating that multiple tissues are damaged through this process of degeneration. The intervertebral disc can displace and herniate in any direction. When the nucleus pulposus herniates into the adjacent vertebral body either superiorly or inferiorly, penetrating the cartilagenous endplate, the resulting lesion is known as a Schmorl’s node. Although the process of Schmorl’s node formation is understood, the causes are still contentious (Burke, 2012). As with most primary degenerative joint diseases, the etiology of Schmorl’s nodes is considered multifactorial. However, age is not usually considered a factor (Dar et al., 2009; Burke, 2012). It is generally thought that the 20 weakening of the cartilaginous endplate or the vertebral body itself facilitates the herniation of the nucleus pulposus (Peng et al., 2003; Dar et al., 2009; Burke, 2012). Compromised endplates are unable to withstand the pressures exerted by the nucleus pulposus. Wagner et al. (2000) attributed increased nuclear pressure to acute axial loading. They are also commonly encountered in regions exposed to more rotational forces (i.e. the thoracic spine) and have thinned intervertebral discs (Ustundag, 2009). Repetitive and generalized physical stress, especially involving flexion of the spine, has been associated with higher incidences of the lesions (Burke, 2012). Schmorl’s nodes have been observed more frequently in men than in women, likely due to heavier load bearing in male spines (Lipson et al., 1985; Prescher, 1998; Sarzi-Puttini et al., 2004; Dar et al., 2009). The zygapophyseal facets are true synovial joints and suffer from the identical degenerative changes of osteoarthritis seen in other synovial joints. They are main facilitators for flexionextension movements and prevent excessive torsion. There is also evidence to suggest they are important in load bearing functions (Fujiwara et al., 2000). Their role in movement and stability precipitates and accelerates facet osteoarthritis. This is particularly true for the cervical and lumbar regions (Prescher, 1998; Sarzi-Puttini et al., 2004), although thoracic involvement has been observed in prehistoric samples (Bridges, 1992). The differences may be because of varying postures, activities and methods of load bearing (Bridges, 1992). Moreover, added stability from the ligaments of the costovertebral articulations may explain the decreased severity of symptoms in the thoracic spine (Sarzi-Puttini et al., 2004). The loss of disc height mentioned above secondarily results in malalignment and increased load bearing of these facets, leading to stressed joint capsules and ultimately degenerative changes (Sarzi-Puttini et al., 2004; Wilmink, 2011). Similar to the osseous changes involved in intervertebral disc disease, degenerated zygapophyseal facets change in morphology. Changes include widening of the joint surface contour, sclerotization and new bone formation, pitting of the joint surface, the development of marginal osteophytes, and most notably eburnation (Sanzhang & Rothschild, 1993; Lovell, 1994; Stirland & Waldron, 1997; Waldron, 2009; Rojas-Sepulveda, 2008). Osteophytes from the zygapophyseal facets can also project into the intervertebral foramina, compressing the nerve roots and vertebral artery (Muto, 2011). Osteoarthritis of the costovertebral and costotransverse joints is not regularly emphasized in the literature. In fact, little attention is given to them in both clinical and archaeological studies. This could be ascribed to their more recognized involvement in rheumatoid arthritis, seronegative spondyloarthropathies and diffuse idiopathic skeletal hyperostosis (Rothschild & Woods, 1991; Arriaza, 1993; Sanzhang & Rothschild, 1993; Sales et al., 2007). Sales and colleagues (2007) note that osteoarthritic costovertebral joints are a rare occurrence outside these disorders, but are still susceptible to the usual osteoarthritic symptoms from excessive movement and pathological loading. The various ligaments in place to stabilize the vertebral column are also susceptible to damage from pathological deformations of the osseous elements and strenuous physical exertions. In some cases, these ligaments, especially the ligamenta flava and longitudinal ligaments, ossify. It has been suggested by Mine and Kawai (1995) that the mechanism of ossification is as follows. The fibers of ligamentous tissues are thinned and torn, and subsequently invaded by capillaries and undifferentiated mesenchymal cells. These cells transform into osteoblasts and osteogenesis ensues. The ligamentous fibers thus calcify and ossify. However, the initial ruination of normal ligamentous tissue is not exclusive to osteoarthritic or intervertebral degradation. Wear and tear of ligaments can result from any number of diseases or traumas involving pathological stress of the normal functions 21 of the spine (Arriaza, 1993; Maat et al., 1995; Hukuda et al., 2000). Its inclusion in the assessment and diagnosis of spinal osteoarthritis may still be valid in association with other more diagnostic criteria as see in the work of other researchers (e.g. Lovell, 1994; Dawson & Trinkaus, 1997; Stirland & Waldron, 1997; Fujiwara et al., 2000; Hukuda et al., 2000; Zukowski et al., 2012). 4.4 Diagnosing Spinal Degenerative Joint Disease Although the clinical definition of osteoarthritis limits its scope to synovial joints (Bridges, 1994; Waldron, 2009; Laplante & DePalma, 2012), the entire spinal anatomy must be given attention. Several paleopathological investigations include alterations to the vertebral body as well as the zygapophyseal facets (e.g. Sandness & Reinhard, 1992; Bridges, 1994; Lovell, 1994; Stirland & Waldron, 1997; Hukuda et al., 2000; Rojas-Sepulveda et al., 2008; Novak & Slaus, 2011). Indeed, even clinical evaluations of spinal osteoarthritis include changes to the vertebral symphyses (e.g. Fujiwara et al., 2000; Niosi & Oxland, 2004; Sarzi-Puttini et al., 2004) since the two types of joints are incontrovertibly linked, and work in tandem throughout the vertebral column to provide movement and support. Furthermore, the two parts share similar osseous changes (e.g. osteophytosis, joint contour changes, surface porosity, sclerotic margins) and etiological factors (e.g. age, sex, physical stress). Vertebral bodies and zygapophyseal facets should not be investigated separately. To keep in line with clinical definitions of osteoarthritis, I suggest the term spinal degenerative joint disease to incorporate both the synovial facets and vertebral symphyses. Adapting Waldron’s (2009) operational definition for osteoarthritis, the differential diagnosis of spinal degenerative joint disease should include two manifestations of either marginal osteophytosis, changes to the joint contour, surface porosity and sclerotic new bone for both the vertebral body and zygapophyseal facets. Eburnation should remain as a pathognomonic indicator of osteoarthritis exclusive to the facets. Schmorl’s nodes are pathognomonic of compromised vertebral endplates, and are highly indicative of great axial stresses placed on the lower spine (Sward, 1992; Wagner et al., 2000; Kyere et al., 2012). They too should be given attention. Ligamentous ossifications should be documented, but never used as the sole indicators for degenerative joint disease as they are also highly associated with other diseases such as diffuse idiopathic skeletal hyperostosis (Arriaza, 1993; Hukuda et al., 2000). 4.5 Limitations to the Study of Spinal Degenerative Joint Disease Paleopathology is not without its limitations. Because of lack of well-documented contexts, archaeological investigations must make necessary inductions from the available evidence. The insufficiency of standardized methods and criteria also hinders comparisons between studies. Some important limitations to the use of spinal degenerative joint disease in assessing prehistoric lifeways are discussed: the differences in methods of scoring and diagnosis, the uncertainty of anthropological aging, and the often absence of clinical and historical documentation. There is a wide variability in the methods for scoring archaeological vertebral degenerative joint disease, and no apparent consensus between researchers. Because of varying methods in the 22 definition, scoring, diagnosis, and statistical computation of osteoarthritis between different researchers, results between studies are often incomparable (Bridges, 1993). In an attempt to appeal to this variety, Rojas-Sepulveda et al. (2008) compared five commonly used diagnostic methods on a Pre-Columbian Colombian series. ‘At least one’ considered one vertebra, one whole region, or one whole column “positive” for the disease if it presented at least one diagnostic criteria (osteophytes, body joint surface contour change, body pitting, zygapophyseal joint surface contour change, zygapophyseal pitting or eburnation). ‘Two together’ considered eburnation as pathognomonic. If eburnation was not present, any two other manifestations (osteophytes, joint surface contour change, pitting) on the same vertebra would have made a positive diagnosis. If one vertebra was positive (either by eburnation alone, or from two other criteria on the same vertebra), the corresponding region and entire vertebral column was also positive. ‘Two separated’ is a variation of the previous, where eburnation is still pathognomonic, but in its absence, any two other manifestations were used for a positive diagnosis, but need not be found on the same vertebra. Any isolated vertebrae were not classified as positive in this scoring system. ‘Only eburnation’ considered eburnation as the sole positive indicator. ‘Pitting excluded’ is a variation of ‘At least one’ except pitting alone was not enough for a positive classification. The results showed “Pitting excluded” as the best of the five for the Colombian assemblage, because pitting seemed to be ubiquitous in both sexes and all age groups at all vertebral regions, affirming Rothschild’s (1997) suggestion that porosity be eliminated as a diagnostic criterion. However, Rothschild’s (1997) contention fails to offer an explanation for the high correlation between pitting and eburnation. To summarize, pitting or porosity is a viable indicator of degenerative changes when in association with other markers. The lesions most likely represent osteopenic subchondral trabeculae and increased osteoclastic resorption directly beneath the subchondral bone plate as a result of instability-related pathologies (Dedrick et al., 1997; Botter et al., 2011). The anthropological assessment of skeletal ages has always been an approximation, especially in adult remains. This is a major limitation on the osteological study of degenerative joint disease, because the disease is highly correlated with age (Jurmain & Kilgore, 1995; Ruhli et al., 2005; Pouletaut et al., 2010; Zukowski et al., 2012). An obvious attenuation of the inaccuracy, but not a cure for it, is a multifactorial approach. When multiple aging criteria are available for approximation, all of them should be used as a comprehensive procedure has been shown to be the most accurate method (Baccino et al., 1999). Methods involving age estimation from the vertebrae should be excluded, as these elements are the dependent variables under study. In addition, the assignment of individual skeletons into standardized age cohorts as suggested by Buikstra and Ubelaker (1994) will allow more valid inter- and intra-population comparisons. For adult skeletons, the age categories most commonly used are young adult (20-35 years), middle adult (35-50 years), and old adult (50+ years) (Buikstra & Ubelaker, 1994). An obvious shortcoming of archaeological materials is the lack of accompanying historical and clinical records. The assumption of decreased quality of life being proportionate to the severity of degenerative changes is partly undermined by modern reports of asymptomatic spinal pathologies (e.g. Sarzi-Puttini et al., 2004; Sales et al., 2007; Dar et al., 2009; Wilmink, 2011; Laplante & DePalma, 2012). Archaeological contexts also often lack necessary ethnographic data. For prehistoric populations, the specific activities of these peoples can only be induced from their material culture and patterning of bony changes. However, the precision to which we can estimate specific activities, the intensity of such activities, and the duration of actions is dubious. The 23 common assumption is that differences in frequency and severity between groups (e.g. different sexes, social classes, and time periods) can be explained by differences in behaviour and activity. The inconsistent contemporary epidemiological results correlating activity and degenerative joint disease prompt Jurmain and Kilgore (1995: 446) to argue that “any such attempts extended to the much less well-documented archaeological past represent an extremely hazardous intellectual venture.” In addition, the genetic predisposition of a small portion of the population to form excess bone, such as more severe osteophytes even in normal conditions, may muddle interpretation (Rogers et al., 1997). Molleson (2007) cautions the necessity for proper documentation, inclusion of a differential diagnosis, comparisons to equivalent normal samples, and review of independent environmental or comparative evidence when estimating activity from skeletal morphologies. 4.6 Summary The application of spinal degenerative joint disease is not without problems. Nevertheless, it has value in answering several archaeological questions, particularly those assessing past human lifestyle and activity. Age is usually equated with degenerative changes. However, it is not the only precipitating factor. Much of the variances in degenerative changes seen in the human spine can be attributed to the biomechanical forces at play (Prescher, 1998). This is likely why the most distinct changes occur in regions of maximum curvature (Bridges, 1992; Bridges, 1994; Novak & Slaus, 2011), movement (Bridges, 1992; Prescher, 1998), and load bearing (Lotz & Loeser, 2012; Novak et al., 2012). Careful considerations of spinal anatomy and its degenerative processes will illuminate the utility of the spine in assessing prehistoric quality of life. In addition, the archaeological context is necessary in linking physical observations of bony lesions to meaningful interpretations of past human activity. With respect to San Jose de Moro and the Moche, the archaeological context provides a unique opportunity to evaluate the physical differences in quality of life as manifested by SDJD between discrete social classes expressed through mortuary evidence. An understanding of Moche sociopolitical organization and religious belief provides a backdrop for which the osteological evidence can be given meaning. 24 CHAPTER 5. THE ARCHAEOLOGICAL CONTEXT OF SAN JOSE DE MORO 5.1 Introduction The Moche (or Mochica) of ancient Peru remain a mystifying culture despite decades of archaeological research. First discovered by Max Uhle in the 19th century, this prehistoric civilization is best described as a society with a complex sociopolitical structure and rich religious iconography. Research terms into warfare, social stratification, human sacrifice, ceramic technology, metallurgy, monumental architecture, urbanism, irrigation, and artwork have become synonymous to Moche. They were the dominant culture of the Peruvian North Coast during the Early Intermediate Period and Middle Horizon of Andean prehistory, approximately AD 100 to AD 800 (Sutter & Cortez, 2005; Chapdelaine, 2011; Villacorta Ostolaza, 2012). Until recently, the Moche were thought to consist of one united polity that later developed state-level organization, with its capital at Huacas de Moche in the Moche Valley (Pillsbury, 2001; Castillo & Quilter, 2010). This paradigm has undergone revision, and currently most researchers agree that two Moche polities in the north and Figure 5.1. Regional map of Peruvian north coast with south existed as distinct cultural spheres separated major Moche sites, and geographic division of northern by the Paijan Desert (Castillo & Donnan, 1994a; and southern cultural spheres. Taken from Chapdelaine, Patterson, 2004; Castillo & Uceda, 2008) (Fig. 5.1). 2011: 194. The northern Moche region encompassed the Jequetepeque and Lambayeque Valleys, and had influences extending further north in the Piura Valley (Chicoine, 2011). The southern Moche sphere included the Chicama and Moche Valleys, expanding territorial control south into the Viru, Chao, Santa and Nepena Valleys through warfare (Castillo, 2001). The growing body of archaeological data is in support of this newer model. Because of this development, the Moche can no longer be considered as a consolidated culture, but portray individual polities that share common religious and sociopolitical elements (Bawden, 1996). The site of prime interest is San Jose de Moro, located in the Jequetepeque Valley in the northern Moche territory. While San Jose de Moro was occupied for more than a thousand years beginning in the Middle Moche period right up to Inca conquest, the San Jose de Moro Archaeological Project has focused on Late Moche development, one of its most dense deposits (Castillo, 2001). The site served as a cemetery and ceremonial center, continually occupied for much longer periods in comparison to neighboring habitational sites such as Pampa Grande and Galindo 25 (Nelson, 1998; Castillo, 2001). Consequently, San Jose de Moro has made great contributions to our understanding of Moche funerary practice, sociopolitical organization, and societal collapse. This paper reviews the archaeological context of the Moche including environmental context, chronology and sociopolitical organization with an emphasis on funerary patterns and social stratification at the ceremonial cemetery site of San Jose de Moro. 5.2 Environmental Context The Moche occupied the coastal strip of northern Peru between the Pacific Ocean and Andean Cordillera. The environment is typically that of a hyperarid desert with little to no rainfall. A series of river valleys are dispersed throughout the coast, and as can be expected, Moche sites are usually clustered around these rivers. Agriculture was made possible by the waters running down from the Andean mountains to the east. To the west, the Peruvian Coastal Current (or Humboldt Current) fostered a rich marine environment, as it does today. Indeed, Moche subsistence took advantage of both cultivatable lands and maritime resources (Sutter & Cortez, 2005; Swenson, 2007; White et al., 2009). Periodic El Niño Southern Oscillation (ENSO) events would cause dramatic shifts in the weather, bringing torrential rains, floods, and migration of marine ecosystems. The implications of these ENSO events have been incorporated into the larger picture of the Moche cultural landscape (e.g. Hill, 2003; Huchet & Greenberg, 2010; Taggart, 2011). Its role in the collapse of Moche society will be discussed in more detail below. 5.3 Chronology Although Uhle was the first to discover the Moche and begin archaeological excavations at Huacas de Moche, it was Rafael Larco Hoyle who first dedicated his life to studying the Moche (Villacorta Ostolaza, 2012) and is considered the father of Moche archaeology (Castillo & Quilter, 2010; Chapdelain, 2011). Larco Hoyle (1948) developed a five-phase chronology for the Moche largely based on changes in the iconic stirrup-spout of Moche pottery (Donnan, 1976; Shimada, 1994) (Fig. 5.2). This seriation was widely used, and its credibility was later verified through radiocarbon dating, becoming instrumental in dating strata from all across the southern Moche coast (Chapdelaine, 2011; Chicoine, 2011). This system was based solely on ceramic vessels collected from the southern sphere. However, with the division of the Moche into the north and south, its application in the northern sphere is dubious. In response, a new sequence has been developed for the Jequetepeque Valley, where Early, Middle, and Late Moche and a Transitional Period replace Figure 5.2. Changes in stirrup-spout form from Moche Phase I through V. Taken from Donnan, 1976: 45. the five phases of the south (Castillo & Donnan, 1994a) (Fig. 5.3). Other northern valleys do not have such a modified chronology yet, but the Jequetepeque sequence is assumed representative of the northern region thus far (Chapdelaine, 2011). Nevertheless, the ceramic 26 chronologies for the northern and southern Moche are incongruent and more work is needed to solidify the equivalences between them. It is only by consensus that scholars allot a range between 100 AD and 300 AD for the beginning of Moche Phase I in the south and Early Moche in the north, but in reality, the actual beginnings are still ambiguous (Chapdelaine, 2011). The Middle Moche begins relatively contemporaneously with Moche Phase III in the south, and partly continues with Moche Phase IV. It is during the final stages of Moche Phase III that drastic stylistic differences are evident between the north and south (Chapdelaine, 2011). The Late Moche in the Jequetepeque Valley corresponds to the latter portion of the southern Moche Phase IV and all of Phase V. Several radiocarbon dates from across the valleys, especially at Huacas de Moche, support Larco Hoyle’s (1948) original seriation (Chapdelaine, 2011). For the Jequetepeque Valley, centralized settlement began in the Early Moche Period at Dos Cabezas (Donnan, 2007). The Moche expanded their territories in two subsequent stages north and south by the Middle Moche Period (Castillo, 2010b) (Fig. 5.4). Occupation at San Jose de Moro begins in the Middle Moche (Castillo & Donnan, 1994b; Castillo, 2001; Zori, 2011), accurately corresponding to the northern expansion of the valley to which it belongs. The emergence of autonomous regions and then later independent polities could have been spurred by expansion of the irrigation systems (Castillo, 2010b). San Jose de Moro seems to have served as a Figure 5.3. Moche ceramic sequence in the northern and southern cultural spheres. Modified from Castillo & Uceda, 2008. communal centre for the surrounding competing polities (Verano, 2006; Castillo, 2010b; Chapdelaine, 2011; Taggart, 2011). Its role as a communal ceremonial center for the valley will be discussed further below. 5.4 Sociopolitical Organization Jeffrey Quilter (2002) has synthesized Moche political organization into four possible models: the single state model, the dual kingdoms model, valley states with no centralized authority model, and a Moche confederation model with Huacas de Moche as its primary center. The single state model originally proposed by Larco Hoyle (1948) requires a monolithic society, but is now dismissed due to the establishment of the northern and southern Moche cultural spheres (Castillo & Donnan, 1994a; Patterson, 2004; Castillo & Uceda, 2008). Agreement beyond dismissal of the first model is still lacking for the other three models. 27 Figure 5.4. Moche expansion stages in the Jequetepeque Valley. Taken from Castillo, 2010b: 92. The dual kingdoms model proposes two independent states, one in the north and one in the south. However, it is doubtful that there was any unity in the north that was comparable to the situation in the south based on uniformity in craft style (Chapdelaine, 2011). The third model suggests that sites with large architectural structures such as El Brujo and Huacas de Moche and those with royal tombs such as Sipan and San Jose de Moro were valley states with no centralized authority. Sites that demonstrate an amassment of power and resources are considered under this model as valley states ruled by a king powerful enough to be politically independent. The fourth model is similar to the third, except that there was some centralization with Huacas de Moche as its capital. This is spurred by the unmatched size and complexity of Huacas de Moche, being the largest site of its time. A comparable candidate for a political capital is Pampa Grande, but the site only emerged towards the very end of Moche chronology (Shimada, 1994). The site of Galindo replaced Huacas de Moche as a center, adopting the Moche Phase V ceramic style that was never introduced at Huacas de Moche (Lockard, 2009). Galindo seems to have been developing contemporaneously with the gradual decline of Huacas de Moche (Lockard, 2009). The northern sphere did not seem to be as united as it was in the south. Therefore, a reformulation of the dual kingdoms model that describes the south as a unified Moche state and the north as a collection of valley states seems most appropriate. 28 The sociopolitical organization of the Jequetepeque Valley differs from that of other regional centers, as it seems to present a mix of regional polities and a centralized state (Catillo, 2010). According to Castillo (2010) and Johnson (2011), the valley was comprised of a number of autonomous political and economic entities, as expressed by different regional material culture and stylistic variation. These separate regions underwent independent cultural evolutions. Defensive sites, such as Cerro Chepen, San Ildefonso, and Cerro Catalina, indicate elements of hostility between the relationships of these polities (Swenson, 2007, 2011). Despite episodes of contention, a sense of uniformity was sustained by valley-level integration through ritual celebration and burials of their elites at ceremonial centers such as San Jose de Moro (Millaire, 2002, 2004; Castillo, 2010b). Collaboration was also necessary in constructing and maintaining primary irrigation systems (Castillo, 2010b). Therefore, Castillo (2010) claims that “ideology, more than coercion or economics, was the principal factor fostering social cohesion and cultural harmonization.” The commonalities in irrigation technologies, iconography and ritual festivities support a centralized system. On the other hand, defensive architecture and fragmentation of communities suggest autonomous isolation. These two paradoxical developmental processes appear to be contemporaneous (Castillo, 2010b), but may have been necessary in ensuring the prosperity of the valley. Indeed, it was the last of the Moche valleys to disappear from the archaeological record. Thus, the Jequetepeque Valley presents a unique situation of parallel development of integration and independence. 5.5 Social Stratification and Burial Contexts Social stratification has characterized majority of Moche archaeology. The necessity for corporate labour in building their massive huacas and the lavishly adorned burials of a handful of individuals suggest a strong degree of social differentiation (Millaire, 2002). Because of a ruling elite, the mobilization of workers was possible on such a large scale for the development of urbanism, craft production, standardization and trade (Hill, 2003; Chapdelaine, 2011). There appears to be at least three social classes (Sutter & Cortez, 2005; Chapdelaine, 2011), well stratified in a Moche social pyramid (Fig. 5.5). The base of this pyramid is composed of commoners involved with the daily tasks of agriculture and construction. Craft specialists, warriors and bureaucrats may represent a middle class (Chapdelaine, 2011), who sought to serve specific interests of the upper class (Makowski, 2008; Bernier, 2010). Finally, the top of the pyramid is occupied by the Moche elite, which may have been divided into three subgroups: a lower elite (regional leaders), an upper elite (high priests and Figure 5.5. Moche social pyramid. Modified priestesses), and royalty (lords) (Chapdelaine, 2011). from Chapdelaine, 2011: 203. Although majority of elite burials are male, women could also hold levels of high status, as demonstrated by the tomb of the High Priestess of San Jose de Moro (Donnan and Castillo, 1992). The prevailing assumption has been that the amount of resources and construction effort of graves is directly proportional to status (Donnan, 1995). Thus, large chamber tombs built with adobe 29 bricks and filled with numerous fine ceramic vessels were reserved for higher ranking individuals, while those burials involving simple pits and few to no material offerings were allotted for the lower class. Three main types of burials have been identified at San Jose de Moro: simple pit burials, bootshaped tombs, and rectangular chambers made with adobe bricks (Nelson, 1998; Millaire, 2002, 2004; Huchet & Greenberg, 2010). Simple pits are typically small graves, often a size large enough for only one individual laid to rest in an extended position. Individuals interred in simple pit burials are accompanied with few to no grave goods. These burials are likely associated with lower class commoners. There is some evidence to suggest that the grave goods associated with a burial may indicate the principle activities during life of those interred (Millaire, 2002; Chicoine, 2011). One association has been found with female graves and spindle whorls and bundles of yarn, proposing that women were actively involved in spinning yarn and weaving fabrics (Donnan, 1995). The boot-shaped tomb gets its name from the shape of its cross-section, which involves a vertical shaft descending down and opening into a horizontal chamber for the body (Fig. 5.6). Once the body is interred, adobe bricks were used to seal off the horizontal portion (Nelson, 1998). According to Nelson (1998), this burial type has only been described at the Jequetepeque sites of San Jose de Moro and Pacatnamu. The literature seems to support this distinction (Millaire, 2004; White et al., 2009). Boot-shaped tombs have been found with multiple individuals interred simultaneously, such as one of the burials at San Jose de Moro containing a child, adult male and young female (Castillo & Donnan, 1994b). A larger number of grave goods versus simple pit burials is typical, and can include fineline ceramics, textiles, copper instruments, Spondylus shells, and llama bones (Millaire, 2002). These burials likely correspond to an artisan middle class and those with some influence. Lastly, the most elaborate burial structures are composed of rectangular chambers constructed with adobe bricks. These were reserved for members of the highest echelons of Moche society. A handful of these graves at San Jose de Moro contained principle women thought to represent the Priestess of the Sacrifice Ceremony in Moche iconography (Castillo & Donnan, 1994b; Taggart, 2011) (Fig. 5.7). This is strongly supported by the presence of a “sacrificial cup” and pointy Figure 5.6. A typical Moche boot-shaped tomb from San Jose de Moro headdress buried with the principle figure, in cross-section. Figure not to scale. Taken from Nelson, 1998: 195. elements present in the iconography. The sacrificial cup and headdress could be tokens of a priestess profession, which were buried with the priestesses after death. An even more lavish tomb was discovered at Sipan in the Lambayeque Valley. The individual buried here who has been named the Lord of Sipan has been identified as the Warrior Priest in Moche iconography (Alva, 2001) (Fig. 7). This is again strongly supported by the similar material culture and iconographic elements, namely the metal backflaps, conical crescent helmet, and crescent nose piercing (Swenson, 2003). Bourget (2008) has also proposed that another 30 burial at Sipan may correspond to Character D from the Sacrifice Ceremony (Fig. 5.7). These discoveries identify the Moche elite as reenactors of specific ceremonies in Moche religion. Other tombs of comparable construction are of a similar nature with varying degrees of lavishness. These chamber tombs are filled with numerous fine ceramic vessels, llamas, bracelets, earspools, ceremonial copper knives, metal artifacts, and a large number of miniature ceramic vessels among others. In addition, several other human skeletons were also interred with the principle figure, probably acting as retainers and sacrificial offerings. There is a growing body of evidence to suggest that tombs were reopened for either reuse by another individual or placement of secondary offerings (Millaire, 2004; Sutter & Cortez, 2005; Huchet & Greenberg, 2010). Nelson (1998) has also demonstrated that bodies may have not been buried immediately after death, but retained outside for considerable time before being interred. The patterns of disarticulation in the boot-shaped tombs at San Jose de Moro studied by Nelson (1998) suggest that the bodies were already in an advanced state of decomposition when they were lowered into the tombs. Imagining this process is reminiscent of the Burial Scene in Moche iconography (Donnan & McClelland, 1979). The dynamic manipulation and revisiting of human remains by the Moche indicate a complex ideology and ritual involving death and the dead (Millaire, 2004). Burials did not serve as mere disposal sites for corpses. Rather, the funerary archaeology of the Moche paints a complicated picture of social stratification and differentiation as well as an active participation by the living (Castillo & Donnan, 1994b; Nelson, 1998; Millaire, 2004). Figure 5.7. The Sacrifice Ceremony scene. Roll-out drawing of a painting on a Moche Phase IV vessel with labeled characters. Taken from Millaire, 2002: 68. 5.6 Moche Collapse In order to understand the reasons for Moche collapse, scholars must remember that the Moche might have never been as unified as previously thought. The existence of several independent polities implies separate demises for each (Chapdelaine, 2011). Some regions may have experienced rapid deterioration, while others underwent a more gradual decline. Different sets of factors may have been involved in collapse of the different states. A case-to-case approach to studying Moche collapse is thus warranted. 31 Two sets of factors (external and internal) acting in tandem likely caused the ultimate demise of the Moche, although not simultaneously across all valleys. It is thought that external factors were only secondary to primary internal distress (Castillo & Uceda, 2008). The primary external factor was environmental instability, specifically the catastrophic weather brought about by major El Niño events (Swenson, 2007; Chapdelaine, 2011; Johnson, 2011). However, it is thought that severe climatic fluctuations were the tipping point to an already waning elite powerbase (Castillo, 2001; Chapdelaine, 2011). Another external factor would have been invasion, either through the replacement of ideologies or through territorial expansion by foreign powers (Swenson, 2007). For the southern Moche, Uceda (2008) believes that at around AD 600 there was a conflict of governance between the theocratic ruling elite and a growing corporatist urban class (Chapdelaine, 2001). As Chapdelaine (2011: 211) eloquently states, “erosion of political power and ideology related to competition within the elite… could best explain the collapse of the southern Moche state”. The Jequetepeque Valley seems to have been the last stronghold of Moche society, before its eventual demise around AD 800 (Castillo, 2001; Swenson, 2007). In contrast to the gradual decline of Huacas de Moche in the south, Moche society at San Jose de Moro in the north experienced a relatively abrupt collapse even with continual occupation into the Transitional Period (Castillo & Uceda, 2008). Indeed, the Late Moche Period is best characterized by social unrest (Swenson, 2007), rigid social inequalities (Swenson, 2011), and collapse (Castillo, 2001). Three contributing factors are highlighted: environmental distress, foreign influence from the Wari culture of the southern highlands, and internal turmoil within Moche society (Castillo, 2000, 2001). Environmental changes have not been extensively studied yet at San Jose de Moro, but archaeologists are confident climatic instability certainly played a part in the collapse based on environmental reconstruction of torrential ENSO events (Taggart, 2011). Mortuary archaeology however has been central to the research at San Jose de Moro. Funerary practices and fineline ceramic styles change dramatically towards the end of the Late Moche and during the Transitional Period (Castillo, 2001). This style incorporates Wari-like and Moche-Wari hybrid motifs, further asserting the effects of external influence. However, no evidence of actual occupation from foreign invaders has been found at San Jose de Moro during the terminal stages of the Late Moche, either in terms of foreign tombs or disproportionate amounts of exotic artifacts (Castillo, 2001). Thus, the archaeological data suggests nonnative influence rather than invasion. In addition, Castillo and Donnan (1994b) give more focus to internal weaknesses of Moche politics. The self-elevation of an oppressive elite class that isolated themselves from the common people and hesitated in their duties of redistribution of goods led to the eventual rebellion of the oppressed (Shimada, 1994; Bawden, 1996). 5.7 Summary The entirety of Moche archaeology could not possibly be given justice in such a brief overview. Truly, the Peruvian North Coast is earning its name as the Egypt of South America. Even so, our knowledge of the Moche is far from complete. Here, emphasis has been given to the correlation between mortuary archaeology and social stratification. These are the most pertinent elements for my thesis research, which focuses on inferring the disparity in quality of life between social classes through the severity of degenerative joint disease in the spine. The mortuary 32 archaeology of San Jose de Moro allows discrete segregation of burial types according to social status. It is clear Moche society was highly stratified. Coupled with episodes of environmental turmoil and the spread of foreign ideology, conflict between the elites and their subjects led to the eventual demise of this culture. Nevertheless, before their disappearance from the archaeological record, the Moche were able to leave behind a rich material culture that has informed archaeologists of ancient sociopolitical organization, iconography and religion, and societal collapse. Their cultural impacts on the landscape will prompt research questions and long-term field projects for decades to come. The investigation of overarching themes such as warfare, politics and religion appear to dominate Moche literature. Although all researchers agree Moche society was highly stratified, it would seem little attention has been given to the understanding of different lifestyles among divided demographic sectors. Beyond simply stating that the ruling elite provided a demand for the production of crafts, and a growing urban lifestyle fueled the construction of massive agricultural fields and monumental architecture, a more focused research question must be asked. Does the apparent stratification that reveals itself through the material culture and iconography likewise reflect itself in the bones of these people? This is the central idea that this thesis seeks to answer. 33 CHAPTER 6. MATERIALS AND METHODS 6.1 Materials This thesis explores the demographic differentiation in quality of life among the prehistoric Moche people of the Peruvian north coast. The vertebral elements from skeletons excavated at San Jose de Moro (N=67) (see Appendices I and II), a ceremonial cemetery site in the Jequetepeque Valley, were examined for degenerative changes of spinal joints (i.e. zygapophyseal facets and vertebral bodies). The sample under study comprises of 48% young adults (n=32) and 52% middle to older adults (n=35), 49% females (n=33) and 51% males (n=34), and 55% pit tombs (n=37), 36% boot tombs (n=24) and 9% chamber tombs (n=6) (Fig. 6.1). The differences between Figure 6.6. Total sample size in study categorized according to males and females were explored, as well age, sex and burial type (i.e. social class). as between age cohorts and burial contexts that are indicative of social status. Given the limitations of time and resources, only individuals from Late Moche were analyzed. The San Jose de Moro archaeological site is located on the north coast of Peru in the La Libertad region, just off of the modern Panamericana highway (Fig. 6.2). Excavations here have been formally conducted since 1991 under the direction of Dr. Luis Jaime Castillo, but the site was well known before then because of the profitable activities of looters. The site has yielded several significant contributions to Moche archaeology, most notably the Priestesses of San Jose de Moro, female burials believed to be the Priestess figure in the Sacrifice Ceremony of Moche iconography (see Chapter 5). 6.1.1 Time Period Occupation at San Jose de Moro was continuous from the Middle Moche period up to ChimuInca times, with its densest levels during the Late Moche period, which covered most of the 7th century AD (Castillo, 2001). Given the limitations of time and resources, analysis focuses on Late Moche (~AD 700-800) burials. Furthermore, previous archaeological investigations have revealed that this period characterizes the strongest disparities between the elite ruling class and commoners in Moche prehistory (Castillo, 2000, 2001; Swenson, 2011), making this occupation level excellent for the present purposes. Castillo (pers. comm., 2013) has also recommended this focus. 34 Figure 6.2. Map of excavation units at San Jose de Moro, Peru. Colours indicate year of excavation from 1991 to 2012. Inset (bottom left) shows map of the protected archaeological zone of San Jose de Moro. Map provided by the San Jose de Moro Archaeological Project. 6.2 Methods The vertebrae from each individual were examined by vertebra and vertebral region for spinal degenerative joint disease (SDJD) at the major joints of the spine: zygapophyseal and intervertebral. Each joint was scored according to the diagnostic criteria below. Individuals were assessed by age and sex (Buikstra & Ubelaker, 1994), social status, and degree of preservation. Data aggregation methods are succeeded by a brief description of the statistical methods employed including Chi square tests in combination with frequency measures. The null hypothesis that no observable differences in lesion severity exist between ages, sexes and burial types is tested through comparisons of lesion frequency and severity as well as Chi-square tests. Given that the manifestation of OA is influenced by several factors, among which are age, sex and activity, we expect to see that at least some difference may be present. 35 6.2.1 Diagnostic Criteria Bony lesions indicative of osteoarthritis and degenerative joint disease were examined using methods derived from those of Sandness and Reinhard (1992), Stirland and Waldron (1997), RojasSepulveda et al. (2008), and Novak and Slaus (2011) (see Chapter 4 for critique of methods surveyed). Lesions are scored on an ordinal scale from 0 (none), 1 (slight), 2 (moderate), and 3 (severe). Criteria for zygapophyseal facets (Fig. 6.3) and vertebral bodies (6.4) include: marginal Figure 6.3. Stages recorded for the manifestation of spinal degenerative joint lesions (marginal lipping, ostephytes, eburnation, surface porosity and new bone growth) of the zygapophyseal facet. Only slight (1) osteophytes and new bone growth were encountered during the study. Scale bars = 1cm. 36 osteophytosis, changes to the joint contour or lipping, surface porosity or pitting, new bone formation on the joint surface, eburnation (exclusive to zygapophyseal facets), and Schmorl’s nodes (exclusive to vertebral bodies). Figure 6.4. Stages recorded for the manifestation of spinal degenerative joint lesions (marginal lipping, ostephytes, Schmorl’s nodes, surface porosity and new bone growth) of the vertebral body. Only slight new bone growth was encountered during the study. Scale bars = 1cm. 37 These criteria are adapted from Waldron’s (2009) operational definition of osteoarthritis and intervertebral disc disease, where at least two of the first four criteria must be observed, or at least one of the last two criteria is observed to indicate the presence of OA (Table 6.1). Operational definition for osteoarthritis Zygapophyseal Facets Vertebral Bodies At least two of At least two of Marginal Osteophytosis Marginal Osteophytosis Lipping Lipping Surface Porosity Surface Porosity New Bone Formation New Bone Formation OR at least one of Eburnation OR at least one of Schmorl’s Nodes Table 6.1. Operational definition for osteoarthritis modified from Waldron (2009) according to zygapophyseal facet and vertebral body. 6.2.2 Points of Observation All vertebrae were examined. However, the sacrum was excluded because of its involvement with the pelvic girdle. Each point of observation was scored separately and later aggregated (see below). Sites of observation are the left and right superior and inferior surfaces of the vertebral body, and the left and right superior and inferior zygapophyseal facets, including the atlantoaxial joint. 6.2.3 Age and Sex Estimation The estimation of individual age and sex has already been accomplished, mostly by student participants of the San Jose de Moro field school. Estimation utilized the methods and guidelines provided by Buikstra and Ubelaker (1994). These records were reassessed and verified according to the same methods and guidelines by the author before inclusion in the sample. Individuals were initially grouped into three age cohorts (Fig. 1). The age categories are young adult (20-35 years), middle adult (35-50 years), and older adult (50+ years). The limited number of older adults (n=2) warranted a merger with middle-aged adults. Thus, analyses with regards to age separate young adults (20-35 years) and middle to older adults (35+ years). Subadults and individuals with ambiguous or unknown age and sex estimations were excluded from analysis. 6.2.4 Social Status Social status of each individual was determined from burial context, particularly burial type: pit tombs, boot-shaped tombs and chamber tombs (Fig. 6.1). Individuals interred in simple pit burials were designated as lower class (n=37), those interred in boot-shaped tombs were designated as middle class (n=24), and those interred in adobe chamber tombs were designated as elites (n=6) (Chapdelaine, 2011). Individuals in elite chamber tombs believed to represent retainers or sacrificial offerings were excluded from analysis, as their membership in a particular social class cannot be 38 verified. For further details on Moche burial practice, see Chapter 5 on the archaeological context of San Jose de Moro. 6.2.5 Preservation Preservation quality of individual vertebral elements was assessed prior to inclusion in the data set. The vertebral body and neural arch were scored separately. Four codes were employed: complete (>75% present), incomplete (25-75% present), very incomplete (<25% present), and absent (not assessable). For the neural arches, completeness were dependent on the presence of right and left superior and inferior zygapophyseal facets. Severely damaged or lacking vertebral elements, such as less than 25% of the spine present, barred inclusion of an individual into the data set. 6.2.6 Statistical Methods For the purposes of manageable statistical analyses, data was collapsed by taking the maximum score for a given joint type (e.g. the maximum score for all zygapophyseal facets of a C3 vertebra was 2, so a score of 2 was assigned to the zygapophyseal facets of the C3 for that individual). This data was further collapsed by taking the maximum score among vertebra of a particular region and joint type as the representative score for that region (e.g. a score of 3 for the vertebral bodies of the cervical region). Severity frequencies were also plotted in order to compare categories within variables, such as males versus females, young adults versus middle to older adults, and pit tombs versus boot tombs versus chamber tombs (Fig. 7.2-7.7). For the purposes of these frequencies, scores of none and slight (unpronounced) were aggregated, as well as for scores of moderate and severe (pronounced). In the case of eburnation, scores of slight, moderate and severe were aggregated as moderate to severe with the consideration that the presence of eburnation, even if slight, represents the complete destruction of cartilage and thus is pathognomonic of SDJD (Rothschild, 1997; Weiss & Jurmain, 2007; Waldron, 2009). The frequency of absent to slight (0-1) and moderate to severe (2-3) manifestations of spinal degenerative joint disease for zygapophyseal facets and vertebral bodies were compared between ages, sexes and burial types (Fig. 7.2-7.7 in Results Chapter). Pearson’s chi-square (χ2) test was used in order to determine whether or not a statistically significant (P<0.05) relationship exists between the variables in question. Chi-square was chosen to test the null hypothesis that no statistically significant differences exist between the different age classes, sexes or burial types. Thus, the observed count will be equal to the expected count. Any disparity between the observed and expected counts is then measured by the test and given a value that suggests whether a significant difference exists between the variables. 39 CHAPTER 7. RESULTS 7.1 Introduction The articular joints in the spinal column were scored according to the severity of spinal degenerative joint disease (SDJD). The sample under study here comes from Late Moche skeletons excavated at San Jose de Moro, Peru. Results from zygapophyseal facets are considered separately from vertebral bodies as these represent two different joint types: synovial and symphyseal, respectively (Fig. 7.1). Visual juxtapositions of lesion severity in Figures 7.2 to 7.7 reveal a Figure 7.1. (a) Anterior view of thoracic neural arch. Superior zygapophyseal facets majority of differences, although face posteriorly (white arrows), inferior zygapophyseal facets face anteriorly (black arrows). (b) Superior view of a lumbar vertebra. Severe pitting and moderate most statistically insignificant osteophytes on the vertebral body margins (black arrows). Scale Bar = 1cm. according to Chi-square testing. 7.2 Zygapophyseal Facets P value Age * ZFCa 9.429 0.009 2 b 1.338 0.720 5 c 3.030 0.387 4 Age * ZFT Age * ZFL Figure 7.2. Percentage of absent to slight and moderate to severe SDJD in zygapophyseal facets among young (n=32) and middle to older adults (n=35). # of Cells with E<5 Chi-square value Relationship One isolated comparison between young adults and middle to older adults incorporating all sexes and burial types yielded a significant relationship in the cervical vertebrae (χ2=9.429, P=0.009) (Fig. 7.2 and Table 7.1). There is a higher prevalence of moderate and severe (pronounced) SDJD in middle to older adults versus young adults, who have a higher frequency of only slight SDJD severity (unpronounced). This result must be taken conservatively as 2 cells in the Chi-square analysis had expected counts less than 5. However, further collapsing of this variable by assigning scores of 0 and 1 as absent and 2 and 3 as present yielded a stronger difference (χ2=7.839, P=0.005) with no cells with expected counts less than 5. Table 7.1. Chi-square values and significance values for relationships between age and joint region. a = zygapophyseal facets of the cervicals b = zygapophyseal facets of the thoracics c = zygapophyseal facets of the lumbars 40 Chi-square value P value 2.630 4.876 1.490 0.268 0.181 0.685 # of Cells with E<5 Relationship Sex * ZFC Sex * ZFT Sex * ZFL 2 5 4 Table 7.2. Chi-square values and significance values for relationships between sex and joint region. Figure 7.3. Percentage of absent to slight and moderate to severe SDJD in zygapophyseal facets among males (n=34) and females (n=33). Pronounced SDJD seems more prevalent in males than in females, particularly in the lumbar region (χ2=1.490, P=0.685) (Fig. 7.3). The cervical (χ2=2.630, P=0.268) and thoracic (χ2=4.876, P=0.181) regions are comparably similar, but with a much greater incidence in the atlas of females, and higher absence in majority of the thoracic and lumbar vertebrae. Chi-square testing does not show that these observations are statistically significant (Table 7.2). Although unsupported by Chi-square testing (Table 7.3), visual assessment of severity frequencies suggest a higher incidence of pronounced SDJD among individuals from pit tombs (n=37) versus a comparable sample size of boot-shaped tombs (n=24). This is particularly evident in the cervical (χ2=7.685, P=0.104) and lumbar (χ2=2.513, P=0.867) regions, with a complete lack of pronounced scores among thoracic vertebrae in boot tombs (χ2=5.235, P=0.514) (Fig. 7.4). Although the frequency of severe cervical cases in chamber tombs seems comparable to that in pit tombs, it should be considered that the entire sample size of chamber tomb individuals is much lower (n=6). It Figure 7.4. Percentage of absent to slight and moderate to severe SDJD in zygapophyseal facets among individuals from pit (n=37), boot (n=24), and chamber (n=6) tombs. 41 Chi-square value P value 7.685 5.235 2.513 0.104 0.514 0.867 # of Cells with E<5 Relationship Burial Type * ZFC Burial Type * ZFT Burial Type * ZFL is included here for completeness. However, it would seem among the 6 individuals belonging to chamber tombs, there is an absence of pronounced manifestations of SDJD in all of the thoracic vertebrae and majority of the lumbar vertebrae. 5 9 8 Table 7.3. Chi-square values and significance values for relationships between burial type and joint region. 7.3 Vertebral Bodies Chi-square value P value Age * VBCa Age * VBTb Age * VBLc 1.899 2.327 2.368 0.594 0.507 0.500 # of Cells with E<5 Relationship Unlike its zygapophyseal facet counterparts, vertebral body SDJD between young and middle to older adults show no statistically significant differences in any particular region of the spine (χ2=1.899, P=0.594 for cervicals; χ2=2.327, P=0.507 for thoracics; χ2=2.368, P=0.500 for lumbars) (Table 7.4). This is supported to an extent by the juxtaposition of frequencies in Figure 7.5. It would seem that there is a general decrease of severity at the junctions between spinal regions in both age cohorts. 4 4 2 Table 7.4. Chi-square values and significance values for relationships between age and joint region. a = vertebral body of the cervicals b = vertebral body of the thoracics c = vertebral body of the lumbars Figure 7.5. Percentage of absent to slight and moderate to severe SDJD in vertebral bodies among young (n=32) and middle to older adults (n=35). The visual comparison of severity frequencies among young and middle to older adult vertebral bodies is similar, with spikes in the mid-cervical, mid-thoracic and lower lumbar regions (Fig. 7.6). Vertebral bodies between sexes and pit and boot tombs show a similar pattern (Fig. 7.7). This pattern is also true for age, sex and burial type in the mid-cervical regions of the zygapophyseal facets, but additional spikes manifest in the lower thoracic and lumbar. 42 Chi-square value P value Sex * VBC Sex * VBT Sex * VBL 1.240 1.959 0.741 0.744 0.581 0.864 # of Cells with E<5 Relationship There are no statistically significant differences in the vertebral bodies according to sex (Table 7.5). However, visual juxtaposition suggests unpronounced thoracic and upper lumbar SDJD in females versus more pronounced SDJD in males from the lower thoracics downward (Fig. 7.6). Cervical SDJD between males and females seems comparable, but with an elevated severity in the C1 of females (Fig. 7.6). 4 4 2 Table 7.5. Chi-square values and significance values for relationships between sex and joint region. Figure 7.6. Percentage of absent to slight and moderate to severe SDJD in vertebral bodies among males (n=34) and females (n=33). Contrary to observations among zygapophyseal facets (Fig. 7.4), vertebral bodies from pit and boot tombs display very similar frequencies (Fig. 7.7). Indeed these are supported by a lack of any significant difference using Chi-square analysis (Table 7.6). Both burial contexts present a pattern of increasing severity frequency at the mid-cervical, mid-thoracic and lower lumbar regions, much like the pattern observed between sexes (Fig. 7.6). Chamber tombs cannot be compared with other burial contexts because of the limited sample size (n=6). However, a consistent frequency of severity is seen across the lower cervicals through to the thoracics and lumbars. This is in sharp Figure 7.7. Percentage of absent to slight and moderate to severe SDJD in vertebral bodies among individuals from pit (n=37), boot (n=24), and chamber (n=6) tombs. 43 Chi-square value P value Burial Type * VBC Burial Type * VBT Burial Type * VBL 6.165 4.409 7.098 0.405 0.622 0.312 # of Cells with E<5 Relationship contrast to the complete absence of severe lesions in thoracic zygapophyseal facets and almost complete absence in lumbar zygapophyseal facets, based on visual inspection alone (Fig. 7.4). 9 8 7 Table 7.6. Chi-square values and significance values for relationships between burial type and joint region. 7.4 Summary All except one of the results show statistical insignificance according to Chi-square testing, (summarized in Table 7.7), but may still be intuitively valuable using visual juxtaposition by providing avenues for interpretation in the absence of significant relationships. Indeed, some visual differences are striking, yet are not reflected through the statistics (e.g. the difference in pronounced SDJD between pit and boot tomb cervical zygapophyseal facets, χ2=7.685, P=0.104, Fig. 7.4). Despite a lack of statistically significant results, the distribution of lesion frequencies throughout the spine may still be telling, even if only slightly, of differentiation between age cohorts, sexes and social classes. Increased age is an important factor for increased severity of SDJD lesions. There are observable differences between males and females, although insignificant, with some regions being more affected than others in both sexes. Social status also plays an important role in the acquisition of degenerative spinal changes, with the lower class manifesting greater frequencies of moderate to severe lesions than their higher ranking counterparts. In summary, differences in the quality of life and activity possibly exist among the Late Moche occupants of San Jose de Moro in terms of age cohorts, sexes and social classes, but a refinement of this research using the avenue of SDJD and others is strongly recommended. Relationship Age * ZFC Age * ZFT Age * ZFL Sex * ZFC Sex * ZFT Sex * ZFL Burial Type * ZFC Burial Type * ZFT Burial Type * ZFL Age * VBC Age * VBT Age * VBL Sex * VBC Sex * VBT Sex * VBL Burial Type * VBC Burial Type * VBT Burial Type * VBL Chi-square value 9.429 1.338 3.030 2.630 4.876 1.490 7.685 5.235 2.513 1.899 2.327 2.368 1.240 1.959 0.741 6.165 4.409 7.098 P value 0.009 0.720 0.387 0.268 0.181 0.685 0.104 0.514 0.867 0.594 0.507 0.500 0.744 0.581 0.864 0.405 0.622 0.312 # of Cells with E<5 2 5 4 2 5 4 5 9 8 4 4 2 4 4 2 9 8 7 Table 7.7. Summary of Chi-square and significance value results comparing multiple variables with joint regions. 44 CHAPTER 8. DISCUSSION 8.1 Introduction The site of San Jose de Moro (SJM) represents continuous occupation from the Middle Moche period up to Chimu-Inca times. However, this study is focused on the Late Moche period (AD 700-800), as it represents the greatest degree of social unrest (Swenson, 2007) and rigid social inequality (Swenson, 2011) that culminated in final collapse (Castillo, 2001) among the Moche periods. Furthermore, it is the densest and most well-represented occupation at the site. If such a stratified social system exists, we can expect to see differences in the frequencies of OA severity between different groups. This hypothesis has been supported by the results just presented in the previous chapter, and further explain in this chapter. Each age cohort presents comparable sample sizes with 32 young adults and 35 middle and older adults. Both sexes are also relatively even in their distribution with 33 females and 34 males. In terms of burial type and social status, commoners from pit tombs and the middle class from bootshaped tombs are relatively similar with 37 and 24 individuals, respectively. Unfortunately, because of the rarity of elites (n=6), meaningful juxtapositions with these individuals may be dubious. Furthermore, only cervical zygapophyseal facets between age cohorts yielded statistically significant results, while all other comparisons were statistically insignificant, possibly in part as a factor of sample size. These factors make the skeletal collection at SJM a challenging assemblage for the study of demographic differentiation through spinal degenerative joint disease (SDJD) in terms of age, sex and social status (elites excepted). San Jose de Moro is positioned along one of the secondary irrigation arteries of the main drainage of the Jequetepeque River. This irrigation canal was established in ancient times during the much later northern expansion of the valley. Despite the prevailing idea that different Moche polities were constantly at odds with each other (Swenson, 2007, 2011) SJM served as a communal ceremonial centre for all occupants of the valley to bury and celebrate their dead (Millaire, 2002, 2004; Castillo, 2010b). Material culture from the site suggests that producing fine ceramic wares and brewing copious amounts of chicha or maize beer were regular activities (Castillo, 2001, 2010), products involved in feastings and festivities during mortuary practices (Swenson, 2007). It would seem that the individuals at San Jose de Moro originated from both local and provincial communities throughout the Jequetepeque despite episodes of contention. Both past and recent literature on Moche archaeology has been centered on cultural adaptation, urbanism, iconography, craft production and specialization, and trade (see Quilter, 2002; Chapdelaine, 2011). Scarce information has been published on the exploration of Moche daily life. The lack of this emphasis in their art and mortuary practices is partly to blame, and indeed when daily life is illustrated it is done so to express religious or ritualistic concepts rather than to demonstrate everyday acts (Quilter, 2002). This marks an opportunity for the current data to contribute to knowledge about the dissimilarity in the quality of life experienced by different sectors of the community. To date, no other formal study has focused on the Late Moche of San Jose de Moro through the use of skeletal material. 45 8.2 Age Clinical literature advocates that increasing age is highly correlated with SDJD severity (Anderson & Loeser, 2010; Loeser, 2011). The statistically significant (χ2=9.429, P=0.009) increased presence of moderate and severe cervical zygapophyseal SDJD among middle and older adults in comparison to young adults supports this. However, the relatively comparable thoracic and lumbar severities between the two age groups questions whether individuals undergo severe stresses early in adult life and reduce physical activity once reaching middle age, as we should expect aggravated lesions throughout the spine as age progresses (Prescher, 1998). This would explain a plateau in the acquisition of more severe lesions among middle and older adults. Lovell (1994) found similar results while working on Harappan skeletons from the Indus Valley, and attributes severe cervical joint changes to accumulated microtrauma from physical stress, as opposed to normal age and sex predispositions. Furthermore, the increased severity in the cervical spine among middle to older Moche adults may indicate a shift in activities from more laborious load-bearing tasks involving the mid and lower back to activities primarily involving the neck. Because SDJD and other osteoarthritic changes are accumulated throughout life a shift in activities may retard the accumulation at the mid and lower back region and increase accumulation at the neck. Currently, the lack of iconographic representation of everyday life hinders any valid claims to changing activities with age. These assertions will remain speculative until or if such time that more telling evidence is excavated. Jurmain and Kilgore (1995) caution that rather than attribute observed degenerative changes to specific activities, it is more valid to restrict analysis to the range of motions inherent to the particular region of the spine. The cervical region allows a greater range of motions versus the thoracic or lumbar spine including flexion, extension, lateral flexion, and rotation. The region is more subject to damage from mechanical loading, as its greater mobility grants more opportunities for compressive and tensile forces from multiple directions (Platzer, 2004). The thoracic region is mainly responsible for rotational movements, and the lumbar vertebrae allow flexion, extension and lateral flexion. Occupational stresses that involve bending, kneeling and stooping over increase the risk of developing osteoarthritis (Busija et al., 2010). These movements involve prolonged flexed postures and punctuated extended postures of the body trunk. Because of the angled zygapophyseal joints and concave unciate joints of the cervical vertebrae, a whole range of motions are available to the neck. Ethnographic evidence, such as the position demonstrated in Figure 8.1, provides an analogy for how prehistoric Moche artisans might have gone about constructing their crafts. Stirland and Waldron (1997) suggest accelerated degenerative changes in the cervical spine from the neck being permanently hunched Figure 8.1. Local San Jose de Moro ceramicist Julio Ibarrola Quiroz replicates ceramic vessels excavated at the site. Notice the stooped position of the neck. Ancient Moche artisans would have likely been in similar positions for prolonged periods of time. Photo provided by the San Jose de More Archaeological Project. 46 forward or to the side in a stooped position (Fig. 8.1). This causes the cervical neck to flex downward (extending the longissimus capitis, splenius capitis, longissimus cervicis, splenius cervicis and semispinalis cervicis attached posteriorly) or sideward (extending the scalene muscles attached laterally). Degenerative changes can also be brought about by habitual burdens to the neck (Hukuda et al., 2000). In order to meaningfully interpret these cervical changes, they must be evaluated in terms of occupational stress. Occupation may be determined from burial contexts (and associated social status), discussed below. 8.3 Sex If we assume that the determined sexes of individuals are indicative of gender status in the society, then meaningful interpretations can be made regarding gender roles at SJM. However, sexual dimorphism in muscle and bone mass must be taken into consideration, as well as changing gender roles among different social classes. In this sample, there is a greater proportion of males with pronounced SDJD in lower thoracic and lumbar facets (χ2=1.490, P=0.685 for lumbars; Fig. 7.3). However, no evident pattern appears between vertebral bodies according to sex. Both males and females have visually similar severities of cervical SDJD (Fig. 7.3 and Fig. 7.6), with slightly higher cervical facet SDJD among females (χ2=2.630, P=0.268), particularly in the atlas. From mortuary archaeological data, Moche archaeologists suggest differentiation in activities among males and females (Verano, 2000; Chapdelaine, 2011; Chicoine, 2011), as will be discussed here. The visual differences in SDJD severity observed here, although statistically unsupported, are evaluated in light of the archaeological evidence in an attempt to explain these differences. Looking for the presence of gender differentiation in the related archaeological record of the region, an oral health assessment of Salinar and Gallinazo skeletons (400 BC-AD 200), predecessors of the Moche in the Moche Valley, revealed a greater abundance of dental caries among females (Gagnon & Wiesen, 2013). This occurs at the onset of agriculture among the Salinar and Gallinazo in the north coast of Peru, where more carbohydrate-rich foods such as maize were introduced into the diet (Lambert et al., 2012). The authors also attribute this abundance of caries to pregnancy, whereby salivary changes during pregnancy predisposed the development of caries (Gagnon & Wiesen, 2013). Males on the other hand shift to tougher, higher protein foods such as meat and marine resources as evidenced by increased in tooth wear over time and relatively stable frequency of caries (Gagnon & Wiesen, 2013). The Osteological Paradox may be at work here since males may have been at a higher nutritional advantage due to their proteinaceous diet than women, and so developed less caries. Ultimately, this finding indicates that sex-specific patterns in oral health already existed in the same region much earlier than the first Moche cities, and perhaps speculatively such gender activity differentiation involved spinal health as well. In males, activities involving the building and maintenance of agricultural fields, monumental architecture and irrigation canals (Swenson, 2003, 2007; Chapdelaine, 2011) necessitated habitual lifting of heavy loads. An Early Intermediate Period (100 BC-AD 100) study on the central coast of Peru in the Lurin Valley demonstrated unequal distribution of labor in this sample, with males having more advanced degenerative joint disease (Pechenkina & Delgado, 2006). Also, warfare remains as one of the key features of Moche culture. This is strongly evidenced in their iconography (Quilter, 2002; Sutter & Cortez, 2005; Sutter & Verano, 2007; Swenson, 2011) and the intrusive signature of 47 Moche conquests in the archaeological sequence (Quilter, 2002; Sutter & Cortez, 2005). Weapons are also highly correlated with male burials (Chicoine, 2011). Large armies would have been required for expansion campaigns, and were almost surely solely comprised of men. The iconographic depiction of naked-bound captured soldiers from several fineline paintings are all male (Fig. 8.2). Moreover, Verano’s (2000) analyses of over 60 sacrificial victims at Huaca de la Luna, presumably captured soldiers from losing armies, were all males from the ages of 15 to 39. The preparation for and participation in war likely involved episodes of severe, acute stress, as evidenced by the numerous antemortem and perimortem fractures present (Verano, 2000). Figure 8.2. Fineline drawing of naked-bound prisoners in procession with (upper right) one having his throat slit, and (below) dead aprisoners and a severred head. Notice the presence of male genetalia on all the prisoners. Drawing by Donna McClelland. Taken from Sutter and Cortez, 2005. In females, cervical severity suggests activities involving load bearing of the neck or habitual stooped positions (Stirland & Waldron, 1997; Hukuda et al., 2000). Ethnographic work done among contemporary rural Mesoamerican communities demonstrates that textile production is a full-time endeavor among women (Hendon, 2006). Archaeologically, Costin (2008) attributes textile production as a largely female endeavor in the Prehispanic Andes, although with some minimal male involvement. In Moche contexts, spindle whorls involved in the production of yarn (Chapdelaine et al., 2001) are found in high association with female burials (Chicoine, 2011). Molleson (2007) describes a female burial from al-‘Ubaid, Iraq where a large spindle whorl and stone pounder were interred with the deceased. The spine of this skeleton showed significantly enlarge lower thoracic vertebrae, narrowed lumbars, and cleft first and second sacral elements. Although dissimilar in many ways, the burial from al-‘Ubaid and the women from SJM may have both weaved impressive textiles in stationary positions (Fig. 8.3). Investigators in other parts of the world have found that cervical SDJD can be a result from carrying loads on top of the head, which puts significant strain on the neck (Bridges, 1994; Lovell, 1994). This is further supported by clinical data (Jager et al., 1997). It is unclear whether Moche women actually practiced such a method since pack animals such as camelids were available, but it nevertheless remains a possibility. The activity is certainly practiced today worldwide among some indigenous cultures, particularly in Africa (Willems et al., 2006; Lloyd et al., 2010; Beaucage-Gauvreau et al., 2011; Porter et al., 2013). 48 The mortuary context of the site supports the idea of a ruling female elite. This is famously evidenced by the Priestesses of San Jose de Moro, women who possessed the most elaborately decorated chamber tombs and held the highest positions of SJM society (Donnan and Castillo, 1992; Castillo, 2010b). Perhaps at SJM, women even across lower and middle social statuses held more influence than men, and thus did not share in the physical burdens of monumental building and large scale farming as men did. This is supported by the decreased presence of moderate to severe lesions in female zygapophyseal facets and vertebral bodies than what is observed in males (Figs. 7.3 and 7.6). However, this phenomenon may not be entirely applicable to neighboring Moche polities. The presence of male leaders in analogous positions of power such as the Lords of Sipan (Alva, 2001) demonstrate that the occupation of women in the highest ranks of society was not universal across the north coast. In addition, European ethnographic sources have painted the perception of weaving and textile working Figure 8.3. Modern Andean women weaving textiles with traditional as an exclusively female task, but techniques using a backstrap loom. Notice that tension is applied to th accounts from 18 century drawings of the fabric using the lower back to pull back the entire contraption (top the north coast of Peru depict women photo). Taken from Virtual Tourist, www.virtualtourist.com. Preserved Moche textile on humeral shaft used to wrap body during actively caring for livestock and tending interment (bottom photo). Photograph author’s own. agricultural fields (Klaus et al., 2009). However, Rojas-Sepulveda and colleagues (2008) in their research of a pre-Columbian Muisca series from Colombia dated three centuries after the disappearance of the Moche found no gender differences in their sample based on SDJD criteria. It would seem both males and females from this nearby culture equally shared in the agricultural work, contradicting the findings of Pechenkina and Delgado (2006) in the Lurin Valley. From the osteological evidence presented here, it would seem to support the latter, with more pronounced lesions in the lower back among males of SJM. 49 8.4 Social Status Differing social statuses imply a division of labor and activities, as supported by varying material culture interred with different burial types (Quilter, 2002; Chapdelaine, 2011). Differing activities would then possibly be reflected in varied patterns of OA affliction. The discussion of social class is limited to commoners from pit tombs (n=37) and the middle class from boot-shaped tombs (n=24) because of the small sample size of elites from chamber tombs (n=6). These two groups possess comparable sample sizes in contrast to chamber tombs. However, intersample comparisons among elites in this collection may be more useful rather than intrasample discussions. Interestingly, Gagnon’s (2008) analysis of the “proto-Moche” or Gallinazo culture (400 BCAD 200) dental health reveals status was not important at the time for the acquisition of quality foods, but it was sex that played a more significant role in this respect. She however argues that “by expanding existing gender differences, Moche elites created the social hierarchies that come to characterize the state” (Gagnon, 2008: 173). Further forward in time, the transition from the Middle Moche to Late Moche periods saw a shift in obedience to funerary norms in pit tombs and thus by extension the lower class (Donley, 2008). Unfortunately, no similar study as of this writing has been produced for the middle class burials. The Late Moche commoners were interred in ways that ignored prevailing burial customs of previous generations. Firstly, significant increases in the sheer number of pit tombs occurs from the Middle to Late Moche. Secondly, infants and only a few adults were interred in pit tombs during the Middle Moche, while Late Moche pit tombs represent all ages (Donley, 2008). Thirdly, body orientation changes from heads towards the south or east in Middle Moche to no specific direction during the Late Moche. Fourthly, where any sort of metal object was usually interred with pit tombs from the Middle Moche, metal objects become rare in Late Moche pit tombs. Whether this was in defiance of the elites by commoners, a decline in the importance of such beliefs by commoners, or exclusion of commoners by elites in their ideological systems, it implies the transition marked a widening chasm between the social classes (Donley, 2008).The differences between commoners and the middle class are most notable through zygapophyseal facets rather than vertebral bodies. A greater incidence of pronounced OA lesions is present among the pit tomb cervical regions (χ2=7.685, P=0.104). Commoners, who were involved with the more physically laborious tasks of society, have more severe arthritic lesions throughout all regions of the spine (Fig. 7.4). These activities would have almost certainly involved the tending and preparing of agricultural fields, maintaining irrigation canals, making mud bricks and the building of monumental architecture commissioned by the local Figure 8.4. Various Moche ceramic vessels chronologically arranged from Southern Moche (Swenson, 2003, 2007; Phase I to V (left to right) on permanent display at the Larco Museum, Lima, Peru. Chapdelaine, 2011). This 50 would have contributed significant strain on the load-bearing joints of the spine, and would have been conducive for the development of pronounced SDJD. Modern studies have shown a positive association between the development of musculoskeletal disorders and labor-intensive agriculture (Walker-Bone & Palmer, 2002; Fathallah, 2010) and manual labour (Holte et al., 2000; Punnett & Wegman, 2004). In particular, cervical changes may be explained by carrying loads on head (Bridges, 1994; Lovell, 1994) or stooping the neck downwards for prolonged, redundant periods (Stirland & Waldron, 1997; Hukuda et al., 2000). Thoracic changes may be related to mechanical movements of the arms and back (Ustundag, 2009). Lumbar changes are almost certainly a reflection of general increased load bearing of the entire upper body (Niosi & Oxland, 2004). Degenerative secondary OA also originates from incidences of trauma (Waldron, 2009), incidences to which commoners in their active lifestyles would have been more prone. Pronounced lesions among the middle class are primarily isolated to the cervical and lumbar regions. The middle class comprised mostly of craftsmen whose works sought to serve the desires of the elite (Makowski, 2008; Bernier, 2010). The production of elaborate ceramic vessels and metal objects (Fig. 8.4), which would have taken large investments of time, necessitated meticulous care and possibly stooped positions (Fig. 8.1). Excavations of workshops suggest these craftsmen were totally dedicated to their craft with little to no involvement in the activities of builders and farmers (Bernier, 2010). Craftsmen likely Figure 8.5. A woman kneading or “wedging” raw clay in utilized muscle groups of the upper torso, while preparation for crafting it into a ceramic vessel. Photo taken from labourers would have likely used the whole Daily Art Muse, www.dailyartmuse.com range of their back muscles. Such a scenario could explain the presence of cervical SDJD among individuals from boot-shaped tombs, but at a severity much less than those of skeletons interred in lower class pit tombs. This then leaves us to question why this pattern is also apparent in middle class lumbar vertebrae. They were likely preparing and kneading their own clay for ceramic vessels, which would produce considerable lower back strain (Fig. 8.5), similar to lower lumbar degenerative disease in an Abu-Hureyra skeleton linked to grinding grain while kneeled on the floor (Molleson, 1994). If we follow the warnings of Jurmain and Kilgore (1995) then the most valid of our assumptions of prehistoric activity are restricted to inferring only the movements involved. As such, middle class craftsmen likely were involved in activities of axial loading. This could range from the handling of their raw materials (e.g. preparing clay by continuously kneading it), but unlikely assisted commoners in their agricultural and constructional duties. At this point, further research is warranted. Isolating interpretations solely to individuals recovered from chamber tombs, it would seem the cervical spine is the most affected region, followed by the thoracic and lumbar vertebral bodies. Zygapophyseal facets of the thoracic spine in elites show a complete absence of any moderate or severe lesions and only minimally occur in the lumbar region. The elite served as the political and religious leaders of the community (Chapdelaine, 2011). Thus, their activities would seem to be 51 primarily administrative and religious. The observed frequencies of moderate to severe lesions may be a reflection of wearing elaborately large headdresses and facial regalia (Fig. 8.6), material culture that has frequently been encountered in royal tombs and signify high rank (Verano et al., 2000). These would be worn during public appearances and ritual rights, but unlikely for prolonged periods. Nonetheless, interpretations of elite activity from OA lesions are highly disputable here considering the small sample size. Furthermore, the presence of chamber tomb SDJD may just as likely be a normal function of age, sex, and genetic factors. Indeed, any interpretation made with the available data is weak. 8.5 Summary Figure 8.6. Moche headdresses made of gilded copper on permanent display at the Larco Museum, Lima, Peru. These adornments, and others like it, have been found in the tombs of high ranking individuals from various sites. Although interpretations of human skeletal material can be extremely useful in informing us of the past, it is not always clear cut. The materials, results and discussion of this study are made in the framework of both available skeletal samples and available archaeological contexts, which are constantly being updated and revised. Uncertainty remains a limiting factor. However, this endeavor is still worthwhile given that relatively few studies have sought to view the Moche of San Jose de Moro away from the traditional foci of the elites and their grand projects. From what has been reviewed above, we can infer a difference in the qualities of life among age groups, sexes and social statuses, although statistically unsupported here. In general, young adults possess similar lesion severities to middle to older adults, but with significantly less lesions in the cervical region. Moreover, interpretations from burial material culture suggest men were more involved in physically intense activities (e.g. construction, combat), while women concentrated with more stationary chores (e.g. textile production). Data from spinal health may reflect this, with more pronounced lumbar severity among men (Figs. 7.3 and 7.5). Finally, commoners were experiencing more physically taxing lives than their higher ranking counterparts. All except one of these conclusions are unsupported by Chi-square testing, but are reflected in visual juxtaposition (i.e. bar graphs in Chapter 7) of lesion severity frequencies (e.g. lumbar severities between males and females in Figure 7.3). The results of this research have unsatisfactorily tackled the hypothesis that differences in OA lesion severity should occur in the SJM assemblage between different demographic sectors due to a stratified social system. It remains unclear to what extent differentiation between ages, sexes, and social classes had on the quality of life among the Late Moche inhabitants of SJM, as reflected in spinal health. This line of inquiry still remains open for more refined investigations. Although the conclusions of this study are far from definite, they provide an avenue for future exploration of Moche daily life, and contribute to the growing discipline of Mochicology. In pursuit of a clearer picture of Moche demographic differentiation, several future directions are suggested. 52 CHAPTER 9. FUTURE DIRECTIONS The results of this research have provided valuable insight into the supporting osteological evidence for a stratified Moche society at San Jose de Moro. Albeit a general lack of statistically significant differences, visual inspection of different degenerative patterns have been identified between age cohorts, sexes and social classes throughout the various regions of the spine. Although these comparisons are not supported by the statistical methods employed here, the results point toward a promising line of inquiry that can be further explored in order to enhance the archaeological record of the north coast of Peru. However, as with all archaeological investigations, there is always room for improvement. These include considerations involving sample size, standardization, multiple indicator approaches, and inter-site comparisons. Firstly, sample size limitation is an obvious issue. The skeletal sample used here consists of 67 skeletons of varying ages, sexes and burial types. All of the Chi-square analyses were conducted with at least 2 cells with expected counts less than 5. This can be resolved through the addition of more individuals into the working sample. Since excavations at San Jose de Moro are ongoing, this remains a viable direction. Secondly, standardization between different studies of OA identification is lacking. Several authors employ their own methodologies in both the diagnostic criteria used and the scale at which they are scored (compare Bridges 1992, 1994; Lovell, 1994; Maat et al., 1995; Stirland & Waldron, 1997; Hukuda et al., 2000; Rojas-Sepulveda et al., 2008; Dar et al., 2009; Novak & Slaus, 2011). Furthermore, because assessment of lesion severity is often conducted on visual terms on an ordinal scale the potential introduction of biases between observers is high. Indeed, no two skeletal populations are alike, and a severe manifestation in one may be only moderate in the other. This can be partly remedied through the inclusion of a series of images of increasing lesion severity for the sample in question (Fig. 6.3 and 6.4). This then gives other osteologists a basis to compare between their findings with others. Surprisingly, this is not done as often as it could be. Thirdly, the focus of this investigation isolated the spinal column as an indicator of the quality of life these ancient peoples endured. Several other elements of the human skeleton may be just as telling and, in keeping with the literature of a multifactorial approach, is needed before more confident statements can be made (Wright & Yoder, 2003). Furthermore, these said additional indicators must be evaluated under the light of the Osteological Paradox in order to appropriately test its utility in discerning past health and quality of life (Wood et al., 1992) The oral cavity, for example, is particularly useful in reconstructing health, past diet and subsistence strategies (Hillson, 2000). Moreover, while this study was limited to adult skeletal remains, an investigation of subadult health across the different demographic sectors (minus sex) can provide an even clearer image of social stratification. Fourthly, the venture of an inter-site investigation including Moche sites beyond the Jequetepeque Valley may be worthwhile in order to know whether the same social structures present at SJM emanated in other polities. Although not definite, it would seem the Northern and Southern Moche spheres were distinct political structures, but united by a common belief system. An inter-site exploration can yield meaningful interpretations of how much of this belief was shared. 53 The Moche of the north coast of Peru are suggested to be highly stratified, as evidenced by their material culture and cultural practices (Quilter, 2002; Chapdelaine, 2011). The osteological material presented in this thesis can possibly be viewed as consistent with this interpretation. However, given the limited results of this study, conservative interpretations should be made in lieu of more evidence. 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Journal of Anatomy, 220, 57–66. 64 APPENDIX I: ZYGAPOPHYSEAL FACET SCORES Number M-U 0311 M-U 0405 M-U 0509-1 M-U 0512 M-U 0601 M-U 0620-1 M-U 0620-2 M-U 0620-3 M-U 0622-2 M-U 0626-3 M-U 0710 M-U 0720 M-U 0731 M-U 0734 M-U 0743 M-U 0808 M-U 0817 M-U 0820 M-U 0902 M-U 0920 M-U 1012 M-U 1013 M-U 1022-1 M-U 1027 M-U 1030 M-U 1032 M-U 1044-1 M-U 1044-2 M-U 1047 M-U 1051 M-U 1060 M-U 1121 M-U 1233 M-U 1504 M-U 1505 M-U 1517 M-U 1521 M-U 1522-1 M-U 1525-1 M-U 1525-2 M-U 1536 M-U 1603-A Age Young Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Young Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Middle Adult Middle Adult Young Adult Middle Adult Middle Adult Middle Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Young Adult Sex Male Female Female Male Male Female Male Male Female Male Female Male Female Male Male Male Male Male Male Male Female Male Female Male Female Male Female Female Male Male Female Female Male Male Male Female Female Female Female Female Female Male Type Boot Boot Pit Pit Boot Pit Boot Pit Boot Boot Pit Pit Pit Pit Pit Pit Pit Boot Pit Pit Pit Pit Chamber Boot Pit Pit Boot Boot Boot Pit Boot Pit Pit Pit Pit Pit Pit Pit Chamber Chamber Boot Pit Period Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche CERVICAL 1 1 2 1 1 1 3 1 1 3 1 1 1 2 2 2 1 3 1 1 2 1 2 2 2 1 2 1 2 2 1 1 1 2 1 3 1 1 THORACIC 0 1 1 1 1 1 1 1 1 1 2 1 1 1 1 2 1 1 3 1 1 1 1 1 1 2 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 2 LUMBAR 1 1 1 1 1 1 2 1 1 2 2 1 0 2 1 2 2 1 1 3 2 1 2 2 2 2 3 1 3 1 2 2 1 2 1 1 1 2 1 1 65 Number M-U 1609 M-U 1710 M-U 1714 M-U 1720 M-U 1726 M-U 1727B-1 M-U 1733 M-U 1740 M-U 1743 M-U 1745-1 M-U 1746-1 M-U 1812 M-U 1814-1 M-U 1814-2 M-U 1814-4 M-U 1913 M-U 1919-1 M-U 1928 M-U 1929 M-U 2003 M-U 2007 M-U 2012-2 M-U 2020 M-U 2101-1 M-U 2107-1 Age Middle Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Middle Adult Young Adult Middle Adult Young Adult Middle Adult Young Adult Middle Adult Middle Adult Middle Adult Sex Female Male Male Female Female Male Female Male Female Male Male Female Male Male Female Male Female Male Male Female Female Female Female Female Female Type Pit Pit Pit Pit Pit Chamber Pit Pit Boot Boot Boot Chamber Boot Boot Boot Pit Boot Boot Boot Pit Pit Chamber Boot Pit Boot Period Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche CERVICAL 2 2 2 2 2 1 2 1 1 1 3 1 1 1 3 2 3 3 1 2 1 1 2 1 THORACIC 1 1 2 1 1 1 1 1 1 1 3 1 1 2 2 3 1 1 2 2 1 1 1 LUMBAR 2 3 2 1 2 1 1 1 2 1 2 1 2 3 3 2 3 2 1 2 2 1 2 2 66 APPENDIX II: VERTEBRAL BODY SCORES Number M-U 0311 M-U 0405 M-U 0509-1 M-U 0512 M-U 0601 M-U 0620-1 M-U 0620-2 M-U 0620-3 M-U 0622-2 M-U 0626-3 M-U 0710 M-U 0720 M-U 0731 M-U 0734 M-U 0743 M-U 0808 M-U 0817 M-U 0820 M-U 0902 M-U 0920 M-U 1012 M-U 1013 M-U 1022-1 M-U 1027 M-U 1030 M-U 1032 M-U 1044-1 M-U 1044-2 M-U 1047 M-U 1051 M-U 1060 M-U 1121 M-U 1233 M-U 1504 M-U 1505 M-U 1517 M-U 1521 M-U 1522-1 M-U 1525-1 M-U 1525-2 M-U 1536 M-U 1603-A Age Young Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Young Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Middle Adult Middle Adult Young Adult Middle Adult Middle Adult Middle Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Young Adult Sex Male Female Female Male Male Female Male Male Female Male Female Male Female Male Male Male Male Male Male Male Female Male Female Male Female Male Female Female Male Male Female Female Male Male Male Female Female Female Female Female Female Male Type Boot Boot Pit Pit Boot Pit Boot Pit Boot Boot Pit Pit Pit Pit Pit Pit Pit Boot Pit Pit Pit Pit Chamber Boot Pit Pit Boot Boot Boot Pit Boot Pit Pit Pit Pit Pit Pit Pit Chamber Chamber Boot Pit Period Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche CERVICAL THORACIC LUMBAR 1 1 3 0 3 1 3 1 0 1 2 1 2 0 1 1 1 0 2 1 1 2 2 2 2 1 3 1 3 1 1 2 1 1 1 1 1 1 1 1 1 2 3 1 1 1 2 2 1 2 0 1 2 0 2 0 1 2 1 1 1 2 1 1 1 2 1 0 2 1 2 2 1 1 1 1 2 2 1 1 2 1 0 1 1 3 1 1 0 1 1 3 1 0 1 1 2 1 2 1 2 2 1 3 2 2 0 1 2 2 1 1 3 3 2 1 1 2 2 1 2 67 Number M-U 1609 M-U 1710 M-U 1714 M-U 1720 M-U 1726 M-U 1727B-1 M-U 1733 M-U 1740 M-U 1743 M-U 1745-1 M-U 1746-1 M-U 1812 M-U 1814-1 M-U 1814-2 M-U 1814-4 M-U 1913 M-U 1919-1 M-U 1928 M-U 1929 M-U 2003 M-U 2007 M-U 2012-2 M-U 2020 M-U 2101-1 M-U 2107-1 Age Middle Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Middle Adult Young Adult Middle Adult Young Adult Middle Adult Young Adult Middle Adult Middle Adult Middle Adult Sex Female Male Male Female Female Male Female Male Female Male Male Female Male Male Female Male Female Male Male Female Female Female Female Female Female Type Pit Pit Pit Pit Pit Chamber Pit Pit Boot Boot Boot Chamber Boot Boot Boot Pit Boot Boot Boot Pit Pit Chamber Boot Pit Boot Period Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche CERVICAL THORACIC LUMBAR 1 1 1 1 0 1 1 1 1 1 2 2 3 2 1 2 2 0 2 1 2 2 3 2 1 3 3 2 1 3 1 2 2 2 1 1 3 3 1 2 1 2 2 1 2 1 2 2 2 2 3 3 1 3 3 1 2 2 3 2 3 1 1 2 1 1 0 1 1 1 1 2 1 68 APPENDIX III: SKELETAL SAMPLE INDIVIDUALS Number M-U 0311 M-U 0405 M-U 0509-1 M-U 0512 M-U 0601 M-U 0620-1 M-U 0620-2 M-U 0620-3 M-U 0622-2 M-U 0626-3 M-U 0710 M-U 0720 M-U 0731 M-U 0734 M-U 0743 M-U 0808 M-U 0817 M-U 0820 M-U 0902 M-U 0920 M-U 1012 M-U 1013 M-U 1022-1 M-U 1027 M-U 1030 M-U 1032 M-U 1044-1 M-U 1044-2 M-U 1047 M-U 1051 M-U 1060 M-U 1121 M-U 1233 M-U 1504 M-U 1505 M-U 1517 M-U 1521 M-U 1522-1 M-U 1525-1 M-U 1525-2 M-U 1536 M-U 1603-A Age Young Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Young Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Middle Adult Middle Adult Young Adult Middle Adult Middle Adult Middle Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Young Adult Sex Male Female Female Male Male Female Male Male Female Male Female Male Female Male Male Male Male Male Male Male Female Male Female Male Female Male Female Female Male Male Female Female Male Male Male Female Female Female Female Female Female Male Type Boot Boot Pit Pit Boot Pit Boot Pit Boot Boot Pit Pit Pit Pit Pit Pit Pit Boot Pit Pit Pit Pit Chamber Boot Pit Pit Boot Boot Boot Pit Boot Pit Pit Pit Pit Pit Pit Pit Chamber Chamber Boot Pit Period Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche 69 Number M-U 1609 M-U 1710 M-U 1714 M-U 1720 M-U 1726 M-U 1727B-1 M-U 1733 M-U 1740 M-U 1743 M-U 1745-1 M-U 1746-1 M-U 1812 M-U 1814-1 M-U 1814-2 M-U 1814-4 M-U 1913 M-U 1919-1 M-U 1928 M-U 1929 M-U 2003 M-U 2007 M-U 2012-2 M-U 2020 M-U 2101-1 M-U 2107-1 Age Middle Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Middle Adult Middle Adult Young Adult Young Adult Middle Adult Young Adult Middle Adult Young Adult Middle Adult Young Adult Middle Adult Young Adult Middle Adult Middle Adult Middle Adult Sex Female Male Male Female Female Male Female Male Female Male Male Female Male Male Female Male Female Male Male Female Female Female Female Female Female Type Pit Pit Pit Pit Pit Chamber Pit Pit Boot Boot Boot Chamber Boot Boot Boot Pit Boot Boot Boot Pit Pit Chamber Boot Pit Boot Period Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche Late Moche 70 APPENDIX IV: DATA RECORDING FORM Burial Number: Age: Sex: Sup. Z-facet Right Inf. Z-facet Sup. Body Site: Context: Date: Sup. Z-facet Feature Inf. Body * = Undesignated typical vertebra Sup. Z-facet = Superior Zygapophyseal Facet Inf. Z-facet = Inferior Zygapophyseal Facet Sup. Body = Superior Vertebral Body Inf. Body = Inferior Vertebral Body Left Inf. Z-facet Sup. Body 0 = None 1 = Slight 2 = Moderate 3 = Severe (Blank) = N/A Inf. Body Preservation: >75% = Complete 25%-75% = Incomplete <25% = Very Incomplete (Blank) = N/A OP LP PT NB EB OP LP PT NB EB OP LP PT NB SN OP LP PT NB SN OP LP PT NB EB OP LP PT NB EB OP LP PT NB SN OP LP PT NB SN Legend: OP = Marginal Osteophytosis LP = Marginal Lipping PT = Joint Surface Pitting NB = New Bone on Joint Surface EB = Eburnation SN = Schmorl's Nodes C1 C2 C3 C4 C5 C6 C7 T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 L1 L2 L3 L4 L5 Element 71 Burial Number: Age: Sex: Body Preservatio n Neural Arch Preservatio n Unc. Proc. Right CV Facet CT Facet OP LP PT NB EB OP LP PT NB EB OP LP PT NB EB Legend: Unc. Proc. = Unciate Process CV Facet = Costovertebral Facet CT Facet = Costotransverse Facet LF = Ossification of the Ligamentum Flavum ALL = Ossification of the Anterior Longitudinal Ligament PLL = Ossification of the Posterior Longitudinal Ligament C1 C2 C3 C4 C5 C6 C7 T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 L1 L2 L3 L4 L5 Element LF Site: Context: Date: Feature Unc. Proc. Left CV Facet CT Facet OP LP PT NB EB OP LP PT NB EB OP LP PT NB EB LF ALL PLL 72