Background Throughout the juvenile period, the knee joint must accommodate several developmental milestones including weaning, crawling, sitting and the attainment of bipedal gait. These activities are related to the magnitude, direction and distribution of mechanical forces passing through the joint and are thought to contribute to the formation of specific trabecular bone signatures. This study aimed to investigate this trabecular bone architecture in the developing distal femur and relate this to the forces acting at key developmental milestones. Methods Micro-computed tomography was performed on 63 specimens within the prenatal to 7-year-old age range. Trabecular bone quantification was conducted in twenty-two volumes of interest (VOI) in the distal metaphysis. Four trabecular bone parameters were analysed within each VOI including; bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp) and trabecular number (Tb.N). Statistical analysis was performed to identify significant differences between different VOIs, and between different age groups. Results Bone parameter values were similar between VOIs in subjects under 1 year old. A reduction of BV/TV during the first two years after birth was highlighted, with the lowest value found between 1 and 2 years old. The decreased BV/TV may be related to reduced mechanical stimulation, compared to the intra-uterine environment, and reduced nutritional supply after birth. Increased BV/TV was observed after 2 years. Significantly higher BV/TV, Tb.Th, Tb.N and lower Tb.Sp were found in sub-cortical VOIs compared to central VOIs. Conclusion Trabecular bone patterns were shown to reflect the forces associated with key developmental milestones.

ObjectivesThere is an increasing understanding of how trabecular bone adapts to biomechanical changes during ontogeny. However, limited research exists regarding the distal tibia, which is important in weight-bearing locomotion as part of the ankle joint. This study aims to document the ontogenetic trabecular patterns of the distal tibia, in addition to changes in its structural heterogeneity.Materials and MethodsThirty-eight distal tibiae, ranging in age from 28 intrauterine weeks to 8 postnatal years, from the Scheuer juvenile skeletal collection were examined. Trabecular bone was analyzed using a quantitative volume of interest approach and qualitative whole bone mapping following microcomputed tomography.ResultsFetal and perinatal tibia lack mature organization and are associated with high bone volume fraction. During the first year of life, there is a decrease in bone volume fraction and an indication of early re-organization of trabecular struts in the distal tibia. After one year of age, the distal tibia exhibits increased trabecular structural heterogeneity.DiscussionThe trabecular architecture of the fetal and perinatal distal tibia lacks mature organization and instead reflects ossification patterns. At these stages, there is a rapid accumulation of bone mass associated with gestational overproduction, hypothesized to be in preparation for subsequent postnatal changes. During the first year of life there is a decrease in volume fraction, associated with constructive regression. It is postulated this is related to changing biomechanical forces associated with the bipedal gait, in addition to growth demands. After one year of age, the distal tibia exhibits structural heterogeneity with trabecular adaption to accommodate specific bipedal stresses.

A novel combination of radiographic colour gradient mapping and radiographic absorptiometry was utilised to examine 96 human distal tibiae from 54 individuals ranging in age-at-death from the foetal to 23 years. The purpose of this was to identify previously undocumented changes in the internal organisation during the development of the distal tibia and determine whether these changes could be described as distinct phases. Previous studies have demonstrated a rudimentary structural organisation in other skeletal elements that mirror more mature patterns of bone organisation. Results showed that the perinatal tibia did not exhibit a rudimentary structural pattern similar to the architecture observed within the late adolescent tibia. This lack of early internal organisation is hypothesised to be related to the rudimentary ossification process that is being laid down around a pre-existing vascular template which will be subsequently modified by locomotive forces. Between birth and 2 years of age, the tibia exhibited a period of regression where radiodensity decreased in comparison to the perinatal tibia. This period of regression was postulated to be due to a combination of factors including changing locomotive forces, weaning and growth resulting in a stage of development which is extremely demanding on calcium liberation from the skeleton. After 2 years of age, the distal tibia demonstrated refinement where radiographic trajectories progressively developed into patterns consistent with adult trabecular organisation. These trajectories are linked to the forces associated with the bipedal gait, suggesting a strong influence of biomechanical forces on the development of the distal tibia.

Volumes of interest (VOI) are commonly assigned to image stacks generated from micro-computed tomography to specify areas for bone quantification. However, the size of the VOI can impact the values obtained for trabecular bone parameters. This study aims to investigate the effect of VOI size by applying VOIs of four different diameters (10%, 15%, 20% and 30% of the antero-posterior width). Ten juvenile right distal femora were included, aged from pre-natal to three years. Smaller VOIs were placed within the largest VOI, with multiple locations used for the same VOI size. The observed parameters included bone volume fraction (BV/TV), trabecular bone thickness (Tb.Th), separation (Tb.Sp), number (Tb.N), degree of anisotropy by mean intercept length (DA.MIL) and star volume distribution (DA.SVD). Statistically significant differences between VOI sizes were found for Tb.Sp, Tb.N, DA.MIL and DA.SVD. A possible effect of localized variation was found due to significantly different values for Tb.Th between VOI locations. The effect related to VOI geometry was reflected by DA.MIL and DA.SVD as no significant difference was found between locations. The minimum diametric strut quantity (DSQ, diameter multiplied by Tb.N) of 4 can be implied based on the zero DA.SVD value found in particular VOIs.

OBJECTIVES:Stable isotope analysis has often been used in neonatal remains from archeological contexts to investigate the presence of a signal of breastfeeding and weaning in past populations. Tooth histology on the other hand might be used as an indicator of birth survival. This pilot study aimed to investigate the feasibility of using stable nitrogen (δ15 N) and carbon (δ13 C) isotope values from neonatal bone collagen to elucidate if values deviating from the adult female average could indicate breastfeeding and co-occur with the presence of a neonatal line (NNL). The combination of these independent indicators might be useful in clarifying the fate of individuals who died around birth.MATERIALS AND METHODS:Bone collagen from 21 archeological human and animal specimens was extracted and analyzed via mass-spectrometry for δ15 N and δ13 C. A verification of the stable isotope results was undertaken using tooth histology on three individuals who were investigated for the presence of a NNL as an indicator of live birth and short survival.RESULTS:The biological age of the human samples varied between 8.5 lunar months (Lm) and 2 postnatal months (Pm) of age. All except one individual exhibited elevated δ15 N values compared to the female average. The histological analyses revealed no NNL for this and two further individuals (n = 3).DISCUSSION:The results indicate that elevated nitrogen values of very young infants relative to a female average in archeological contexts are not necessarily associated with a breastfeeding onset signal, and therefore cannot be used exclusively as a proxy of birth survival. The elevation might be possible due to various reasons; one could be nutritional, in particular maternal stress during pregnancy or a metabolic disorder of mother and/or her child. In those cases, the evaluation of a NNL might reveal a false breastfeeding signal as seen for two individuals in our sample who have elevated nitrogen values despite the fact no NNL could be observed. Overall, our data support the growing awareness that bone collagen δ15 N values of neonates/infants should not be used as a proxy for breastfeeding or birth survival on its own.

Skeletal age estimation of living and deceased juvenile individuals is the only pillar of the biological profile that can be assessed accurately by the forensic anthropologist when biological identity is unknown or in question. This accuracy can be attributed to the well-defined chronology of developmental milestones that the juvenile skeleton undergoes from the point of ossification through to the attainment of maturity. These developmental milestones have been extensively documented within the anthropological literature and have resulted in the formulation of aging standards that can be used in the assessment of biological age. During development, age is typically estimated via assessment of the appearance, changing morphology, and the fusion of ossification centers. Each of these events can be assessed via a combination of morphological and metric techniques. This chapter will discuss the growth and development of the skeleton and will provide an overview of the general principles and primary methods used in the estimation of skeletal age from the juvenile skeleton.

Multiple developments for juvenile age estimation have occurred over the last decade, including advancements in methodology and practice. In particular, there has been an effort to encompass human variation through the creation of population-based aging standards that acknowledge ancestral, secular, and socioeconomic differences. The need to estimate the age of living children has also become increasingly necessary in modern times. Thus, there has been a surge in the use of medical technologies, such as conventional radiography, magnetic resonance imaging, ultrasound, and computed tomography, to develop standards associated with age estimation. This chapter highlights those works in addition to papers incorporating less mainstream, albeit just as important, trends.

Radiographic fracture date estimation is a critical component of skeletal trauma analysis in the living. Several timetables have been proposed for how the appearance of radiographic features can be interpreted to provide a likely time frame for fracture occurrence. This study compares three such timetables for pediatric fractures, by Islam et al. (2000), Malone et al. (2011), and Prosser et al. (2012), in order to determine whether the fracture date ranges produced by using these methods are in agreement with one another. Fracture date ranges were estimated for 112 long bone fractures in 96 children aged 1-17 years, using the three different timetables. The extent of similarity of the intervals was tested by statistically comparing the overlap between the ranges. Results showed that none of the methods were in perfect agreement with one another. Differences seen included the size of the estimated date range for when a fracture occurred, and the specific dates given for both the upper and lower ends of the fracture date range. There was greater similarity between the ranges produced by Malone et al. (2011) and both the other two studies than there was between Islam et al. (2000) and Prosser et al. (2012). The greatest similarity existed between Malone et al. (2011) and Islam et al. (2000). The extent of differences between methods can vary widely, depending on the fracture analysed. Using one timetable gives an average earliest possible fracture date of less than 2 days before another, but the range was extreme, with one method estimating minimum time since fracture as 25 days before another method for a given fracture. In most cases, one method gave maximum time since fracture as a week less than the other two methods, but range was extreme and some estimates were nearly two months different. The variability in fracture date estimates given by these timetables indicates that caution should be exercised when estimating the timing of a juvenile fracture if relying solely on one of the published guides. Future research should be undertaken to compare these methods on a population of known fracture timing, and to better understand the relationship between age of the individual, skeletal health, fracture healing rates, and radiographic characteristics of fracture healing.

This chapter provides a brief outline of the early embryological development of the human body as a whole and sets the scene for the more specific developmental aspects of the skeleton that are discussed in the subsequent chapters. Key terminology is defined and the chapter charts development from the second week following fertilization. The establishment of the three germ layers of the embryo is summarized and their fundamental importance to the subsequent development of the major body systems is highlighted.

This chapter begins with a description of each of the adult cervical, thoracic, lumbar, sacral and coccygeal vertebrae. The early embryological development of the vertebral column is considered and follows on from the stage outlined previously in Chapter 4. The ossification of each bone is then considered describing each vertebra from the time of initial ossification to the attainment of adult form. This section is presented in three parts dealing with primary centres of ossification, secondary centres ossification and patterns of epiphyseal fusion. The final section within this chapter presents a summary of key osteological events used in age estimation. Practical notes are also included to provide guidelines on the sideing of remains and how to orientate them to achieve correct identification.

This chapter is presented in five sections considering the (1) femur, (2) patella, (3) tibia, (4) fibula and (5) bones of the foot. Initially, in each section, a description of the adult bone(s) is provided. The early embryological development of the femur, patella, tibia, fibula and foot is considered and follows on from the stage outlined previously in Chapter 4. The ossification of each bone of the lower limb is then considered, describing each element from the time of initial ossification to the attainment of adult form. Where appropriate, this section is presented in three parts dealing with primary centres of ossification, secondary centres of ossification and patterns of epiphyseal fusion. The final section within each part of this chapter presents a summary of key osteological events used in age estimation. Practical notes are also included to provide guidelines on the identification, orientation and sideing of elements.

This chapter is presented in two sections with the first considering the sternum and the second considering the ribs and costal cartilages. Initially, a description of the adult sternum and the typical and atypical ribs is provided. The early embryological development of the sternum and ribs is considered and follows on from the stage outlined previously in Chapter 4. The ossification of each component of the sternum and ribs is then considered, describing each element from the time of initial ossification through to the attainment of adult form. This section is presented in three parts dealing with primary centres of ossification, secondary centres of ossification and patterns of epiphyseal fusion. The final section within each part of this chapter presents a summary of key osteological events used in age estimation. Practical notes are also included to provide guidelines on the identification and orientation of elements, and the sequencing and sideing of ribs.

This chapter is presented in four sections considering the following: (1) humerus, (2) radius, (3) ulna and (4) bones of the hand. Initially, in each section, a description of the adult bone(s) is provided. The early embryological development of the humerus, radius, ulna and hand is considered and follows on from the stage outlined previously in Chapter 4. The ossification of each bone of the upper limb is then considered, describing each element from the time of initial ossification to the attainment of adult form. Where appropriate, this section is presented in three parts dealing with primary centres of ossification, secondary centres of ossification and patterns of epiphyseal fusion. The final section within each part of this chapter presents a summary of key osteological events used in age estimation. Practical notes are also included to provide guidelines on the identification, orientation and sideing of elements.