Case Study of Possible Endocrine Disorder in an Ancient Maya skeleton from the Chan site, Belize Anna C. Novotny1, Samantha Mitchell1, Kate M.W. Hall1 Texas Tech University, Department of Sociology, Anthropology, and Social Work1 Introduction The Chan site is an ancient Maya hill-top village located in west central Belize (Figure 1; Robin 2012). The site was occupied continuously for over 1800 years, from 800 BC – AD 1200 (Robin 2012). The site’s occupants constructed a moderately sized village center with two pyramids facing each other on either side of an open plaza. Excavations uncovered 25 individuals in 19 graves within these structures. The majority of these burials were placed in Structure 5, the central pyramid on the eastern side of the plaza. Burial 9, a single individual interment dating to 350 BC - AD 100. was particularly well preserved compared to other skeletal remains recovered from the site (Figure 2; Novotny 2007). The individual in Burial 9 was observed to have perimortem fractures to the 12th thoracic vertebra, possibly one of the lumbar vertebra as well, to three lower ribs, and woven bone on the pleural aspect, medial 1/3, of the middle ribs (3-10) (Figures 3-5). Further observation revealed other instances of non-specific stress markers. In addition, all skeletal elements seemed brittle and light-weight. It was unclear whether the seemingly poor quality of the bone was in fact taphonomic or whether it was related to a broader pathological process that produced the fractures observed in the thorax. Here, we describe the location and type of bone reaction throughout the skeleton and detail the fractures to the thorax. We also conducted a histological analysis of the individual in Burial 9 as well as a second individual from Structure 5 to assess bone quality and taphonomy. Discussion and Conclusion Osteological analysis shows a persistent systemic stress beginning in early childhood, as attested by the hypoplasias (RI1, RC1) and healed cranial porosity. The osteopenia observed throughout the skeleton is of unknown etiology. The apparent systemic nature of the osteopenia suggests an imbalance between bone formation and resorption due to an endocrine disorder, nutritional deficiency, or infectious disease process. The ribs and vertebra may have fractured secondary to the process that caused the osteopenia. However, they could have been the result of a local traumatic event. The degree of healing on the rib fractures suggest they may have occurred prior to the vertebral fracture. The mixed reaction of abnormal bone formation on various long bones (femora, clavicles, tibia) suggests a chronic immune response beginning prior to the active pathological process affecting the ribs. The woven bone on the pleural aspect of the ribs may be indicative of an upper respiratory infection or other infectious disease affecting the lungs. As broken ribs typically only cause infection when they pierce the skin, the woven bone could have been caused by a lung infection already in progress. The histology suggests that the individual in Burial 9 was undergoing some sort of imbalance affecting bone remodeling. When compared to modern males of the same age range, the Burial 9 rib falls closer in C/T ratio to endocrine disordered individuals than to normal bone (Table 2). The young age at death, sex, osteopenia, rib and vertebral fractures, C/T ratio, and suppressed immune response are consistent with hyperparathyroidism. Osteomalacia is also a possibility (Brickley et al., 2007). However, multiple processes could have been active at once to produce the pathological processes observed here. Results Osteology The individual suffered from chronic stress starting in early childhood as evidenced by LEH on his RI1, RC1. There was mixed (active and healing) abnormal bone formation on several bones, including the medial clavicles, femora, left tibia, pubis, ribs, and mandible. Histology While the macroanatomical structure of the Burial 9 rib was preserved, there were few discernable microanatomical features (Figure 8). There were microanatomical features evident from the Burial 9 tibia and the Burial 8 rib samples, although they are not readable and no measurements were taken (Figures 6 and 7). Both samples appear to have endured similar diagenetic patterns; root fragments and cracking are clearly discernible. The key piece of information that these samples provide is their striking difference in preservation when compared to the rib of Burial 9 (Figure 8). While the exact processes are difficult to discern, the rib of Burial 9 was affected by some process pre-mortem that contributed to its poor preservation. Figure 1: The Chan site is indicated by the red star Figure 2. Burial 9 (above); ceramic vessels Figure 3. Fractured ribs 11 and 12, superior aspect Figure 6. Histology section of control (Chan Burial 8 rib). Table 1. Summary of osteology results: lesion location and type Bone, Side Location Type of abnormality Cranial fragments Ectocranial surface; near sutures Pinpoint porosity, healed Mandible, right Periosteal surface; alveolar process Pinpoint porosity, healed Clavicle, right and left Medial 1/3; inferior aspect; external surface Unifocal, lytic lesion with well-defined boundaries; active Clavicle, right Medial 1/3; superior aspect; external surface Mixed reaction (woven and sclerotic); possible unifocal bone loss Rib fragments 3-10, left and right Vertebral 1/3 and medial 1/3 Periosteal surface; woven bone formation; active and healing Rib 10-12, right Vertebral end, greenstick fracture Callus formation, woven bone; cloaca on rib 11 12th thoracic vertebra Body, compression fracture No callus; woven bone formation Pubis, right Superior and inferior pubic ramii Periosteal surface; woven bone formation; active Femur, right and left Entire diaphysis; circumferential Mixed reaction (woven and sclerotic bone formation) Tibia, left Middle 1/3 of diaphysis; anterior aspect Materials and Methods Sex Skull and pelvis morphology were indicative of a male individual. The diameter of the left femoral head was 43.26 mm, within the range for a male individual (Buikstra and Ubelaker 1994). Age Age at death was approximately 23-25 years based on the lack of fusion of the medial clavicle (left and right). The lack of wear on the second and third molars in both the maxilla and mandible was minimal, which supports a young age at death (White and Folkens 2005). Histology Three bone fragments were chosen for histological analysis – a fragment of a rib from Burial 9, a tibia fragment from Burial 9, and a long bone fragment from Burial 8 as a control. Burial 8 was recovered from the same structure as Burial 9, was in a similar grave structure (stone lined cyst), and dates to approximately the same time period (Late Preclassic). The preservation of microanatomical features was assessed and the ratio of cortical area to total area was measured to compare to modern samples of normal bone and samples of known disease etiology (Table 2). Analysis of these samples also allowed us to assess possible taphonomic changes to different parts of the body. Slides were prepared according to methods outlined in Paine (2007). Figure 4. Compression fracture,12th thoracic vertebra Figure 7. Histology section of Chan Burial 9 tibia. Table 2. Comparison of histological data   Cortical Area Total cross-sectional area C/T ratio Chan Burial 9 rib 19.4 57 0.34 Endocrine disordered ribs 16.65 48.5 Normal (20-29) year old male ribs 26.5 58.7 0.48 Figure 5. Active new bone formation, pleural aspect, rib fragment (3-10). Figure 8. Histology section Chan Burial 9 rib. References Available upon request