Inter-population differences in acetabular senescence: relevance in age-at-death estimation.

Since investigation of the timing of the skeletal traits among the acetabula of different populations is lacking, this study aims to evaluate the relevance of geographical origin in the acetabulum aging process and in the usability of the SanMillán-Rissech aging method. The acetabula of 826 European North Americans derived from the Bass Collection (USA) have been analyzed and compared with 611 Portuguese acetabula from the Luis Lopes Collection (Portugal) applying the most updated acetabular age estimation technique (2017). After evaluating and comparing the acetabular aging rates between both populations by Mann-Whitney U tests, the inaccuracy values (bias and absolute error) were analyzed and compared using population-specific reference samples and using references differing in geographical origin by Wilcoxon tests. In general terms, the North Americans age faster than the Portuguese, especially the females, reaching the consecutive acetabular stages at younger ages. Regarding the SanMillán-Rissech method accuracy, using population-specific reference samples produces, as a general rule, better outcomes. In addition, an exhaustive meta-analysis of inaccuracy values has demonstrated that this method provides better estimation values than pubic symphysis and auricular surfaces regardless of the geographic coherence of the reference sample. These inter-population skeletal differences are derived from different factors than age, highlighting the impact of both biological and social background on age estimation. A thorough analysis of the skeletal age-based timing becomes essential to understanding, deciphering and being able to minimize bias and potential inaccuracy or even counteract them when applying the age estimation methods to different populations.

Morphological Differences between Sheep and Goat Calcanea Using Two-Dimensional Geometric Morphometrics.

The distinction between bones of sheep and bones of goats is a difficult issue in zooarchaeology. Several studies undertaken in the past to facilitate this task have relied upon both qualitative criteria and osteometry. Geometric morphometrics has proved to be a powerful tool to evaluate morphological differences in a rigorous and detailed manner. This study aims to analyse variations in the morphology of the calcaneum among sheep and goats based upon two-dimensional geometric morphometrics (GM). Twenty landmarks were selected on the surfaces of 79 calcanea (47 sheep and 32 goats) to calculate the principal components of shape variations among these specimens. Clear interspecific differences in the morphology of this bone were extracted. Most are located on the calcaneal tuber and neck, the sustentacular tali region, the articular surfaces of both the malleolus and the cubonavicular. Furthermore, the use of GM methods has enabled us to assess small but significant amounts of geometric variation that are difficult to measure using traditional morphometric techniques. They provide a new and useful perspective to what is already known in the published literature. Our results shed new light upon the possibility of the existence of qualitative features that may help to distinguish caprine breeds.

Pathological and sub-pathological changes in European rabbit bones: Two reference cases to be applied to the analysis of archaeological assemblages.

OBJECTIVE: To provide prevalence data for future comparative analysis of the health status of rabbits (Oryctolagus cuniculus) accumulated in the archaeological record. MATERIALS: Two contrasting assemblages were analysed for pathological and sub-pathological changes: 1) an assemblage of domestic modern rabbit bones; and 2) a non-anthropogenic accumulation of archaeological rabbit remains. METHODS: The lesions observed macroscopically, under magnification, and radiographically in both assemblages are quantified and described. RESULTS: In the first assemblage, pathological and sub-pathological changes mostly affected the lower limb bones and primarily took two forms: diaphyseal periosteal proliferation and hypervascularised distal physes. Differential diagnosis of the periosteal proliferation suggests that pododermatitis is the most probable cause. In the second assemblage fractures were the most common lesions, but isolated examples of hypervascularised physes, periosteal proliferation, and musculo-skeletal stress markers were also identified. The pathological changes recorded is typical of a naturally-accumulated population of wild rabbits. CONCLUSIONS: The prevalence of pathological and sub-pathological skeletal changes in the rabbits, and thus their health status, are closely related to living conditions. This study demonstrates the value of systematically recording pathologies in rabbit bones. SIGNIFICANCE: We contribute new data to help understand rabbit interactions with humans in the past and also the environment they inhabited. LIMITATIONS: Working with modern samples frequently means only incomplete skeletons are available for study. In these cases lesion prevalence always needs to be interpreted with caution. SUGGESTIONS FOR FURTHER RESEARCH: Paleopathological studies of rabbit remains are remarkable for their absence. Further exhaustive research in this area is advised.

Direct emergence of the conus artery from an independent ostium. A cadaveric study on a Spanish sample

The main purpose of this study was to evaluate the frequency with which the conus artery originates from an independent ostium in the right aortic sinus. Twenty-five adult hearts (3 females, 5 males and 17 unknown sex), from the body donation program of the University of Girona, were analysed. After intravascular injection of natural coloured latex in the coronary ostia, the origin of the conus artery and its distribution pattern were analysed by microdissection. Three of the 25 hearts analysed (12.0%) displayed the direct emergence of the conus artery from a discrete ostium in the right aortic sinus: in two specimens (8%) showing a single ostium for the independent conus artery, and in one heart (4%) two ostia for two independent conus arteries. In all cases, the independent conus arteries were shorter than the coronary artery and extended up to the anterior wall of the right ventricle, coinciding with the observations of previous authors. The independent conus artery may be an important source of collateral blood flow to the infundibulum. It may be an important source of apex and interventricular septum collateral irrigation. To ascertain the origin of the conus artery and its distribution is clinically important, particularly in obstructions of the anterior interventricular artery. The independent conus artery's collateral perfusion can both obscure the detection of any ischaemic modification in the apex and septum regions, and serve as a therapeutic source. Consequently, interpretations of the coronary occlusion clinical test should take this vascular channel into account

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Application and analysis of the Rissech acetabular adult aging method in a Colombian sample.

The classical age indicators of the innominate have been the pubic symphysis and auricular surface. However, recently, the acetabulum has been highlighted as an indicator of adult age, with applicability in young, middle-aged, and older adults. The Rissech acetabular method was developed in a Portuguese population and tested in European and European-Americans, giving estimates within 10 years of age in more than 89% of the sample. The main goal of this paper is to test the Rissech acetabular method in a modern South American sample. The material used for the study was 184 women and 378 men from a Colombian-documented skeletal collection. The obtained morphological scores from the acetabulum were analyzed through the IDADE2 web page, a Bayesian statistical program that estimates a relative likelihood distribution for the target individuals, produces age estimates, and provides 95% confidence intervals. Results showed this method is useful in the modern Colombian population with an average absolute error of 10.63 years in females and 9.44 years in males. These errors are similar to those obtained in other European and North American samples when this method was performed and similar or lower than those obtained when the 3 classical aging methods (Suchey-Brooks, Buckberry-Chamberlain, and Lovejoy) were applied in the same collection (absolute error: 10.29 years ♀ and 9.05 years ♂ in Suchey-Brooks, 12.5 years ♀, and 12.17 years ♀ in Buckberry-Chamberlain, and 13.54 years ♀ and 10.99 years ♂ in Lovejoy). Although Rissech's method was developed in a Western European sample, the results of this study indicate its applicability in modern Colombian samples with reasonable accuracy.

The acetabulum as an adult age marker and the new IDADE2 (the IDADE2 web page).

OBJECTIVE: In 2006, an age estimation method was proposed utilizing Bayesian inference to interpret age-progressive changes in the acetabulum. This was accompanied by the IDADE2 software to facilitate calculations. However, the MS-DOS operating system on which the software was based became obsolete. The main goal of this article is to present the new IDADE2, which incorporates web-based facilities. MATERIALS AND METHODS: The original IDADE2 has been re-written in R and presented as a web page. As in the original, this web page uses Bayesian inference to estimate age of unidentified individuals. The materials used to create the reference datasets of this web page include acetabular scores from documented skeletal samples from Spain (n = 24♀ and 52♂), Portugal (n = 317♀ and 294♂), and the US (n = 370♀ and 456♂). RESULTS: The IDADE2 website has eight sections. Six of these are informative to guide the user. The other two (Option 1 and Option 2) are dedicated to estimating age at death. Option 1 allows users to estimate the age of individual(s) in their test sample based on our reference data of acetabular scores. Option 2 allows users to estimate age from the acetabulum with their own reference and test collections or-if the users prefer-another age marker and method of choice. DISCUSSION: The IDADE2 website is applicable both to forensic anthropological casework on single individuals and to bioarchaeological analyses of large skeletal samples. This website is easy to use and freely accessible, responding to previous critiques and incorporating method advancements.

Application of the recent SanMillán-Rissech acetabular adult aging method in a North American sample.

Recently, a renewed acetabular aging methodology was published by San-Millán et al. (Int J Leg Medicine, 47, 131: 501-525), refining the variables associated with acetabular fossa aging in different populations. Due to its novelty, this method has not yet been examined in any other population, other than it was developed and originally tested on. Therefore, the main goals of this study are two-fold: (1) to evaluate the accuracy of SanMillán-Rissech's method in a North American sample made up of 826 white (456 males and 370 females) individuals from the Bass Collection and (2) to determine whether the revised methodology shows higher rates of accuracy than the original methodology (J Forensic Sci, 31, 51(2): 213-229). Scores obtained by both methodologies were analyzed via a Bayesian statistical program (IDADE2) that estimates a relative likelihood distribution for the target individuals, produces age-at-death estimates, and provides 95% confidence intervals. Even though the revised method was developed using a Western European collection, the results demonstrate that it is also applicable to North American samples with reasonable accuracy results, i.e., an average absolute error of 7.19 years in males and 9.65 years in females. However, accuracy in females is significantly lower than in males, likely due to their higher morphological variability associated with different factors other than age. The significantly better performance of the revised methodology compared with the original is also been confirmed by the current findings from this North American sample, supporting the renewed system as a better aging methodology. Although work on further populations is needed, previously and current results should encourage professionals to include the acetabular method in forensic and archaeological laboratories routines.

The influence of bone loss on the three adult age markers of the innominate.

To evaluate the influence of bone loss on the three adult age markers of the innominate, 30 males and 30 females aged between 16 and 80 years coming from the British Coventry collection were analyzed. The pubic symphysis, auricular surface, and acetabulum age variables were evaluated following the descriptions of Schmitt, Buckberry-Chamberlain, and Rissech, respectively. The second metacarpal cortical index was used to evaluate bone loss. Possible sexual differences in metrical variables were explored by a Student t-test taking into account the entire sample. The possible relationships between the cortical index and the three age methods' stages were assessed by the Kruskall-Wallis test and Spearman's correlation coefficient. There were no sexual differences in the cortical index. In general, we observed no significant differences between the cortical index in the different stages of the pubic symphysis, auricular surface, or acetabulum variables in men and women. Most correlation coefficients are negatives, and their absolute values are between 0.001 and 0.44, indicating an extremely low influence of bone loss on the analyzed variables. Our findings suggest little influence of bone loss in the three ageing methods. However, further research on this topic is necessary. This is the first study to analyze the influence of bone loss in the ageing changes undergone by the variables of the three adult age indicators of the innominate taking into account both sexes.

Shape variability of the adult human acetabulum and acetabular fossa related to sex and age by geometric morphometrics. Implications for adult age estimation.

This study aims to explore shape variability of the acetabulum during the human adult life span, in relation to sex and age. The human acetabular shape was analysed in 682 os coxae from three different documented skeletal collections from the Iberian Peninsula. Two landmarks and thirty-two sliding semi-landmarks were used for the geometric morphometric procedures and a clock-wise standard was used for orientation. The 180° meridian (6:00) line was positioned over the midpoint of the acetabular notch and 36 reference points in 10° increments along the rim were marked. Data showed that size, sex and age significantly influence acetabular shape variation. Sex differences were significant in individuals younger than 65 years old and were characterised by males exhibiting relatively extended acetabular rim profiles from 10:00 to 1:00, narrower acetabular notches, and reduced acetabular fossae. In addition, three main age-related changes occurred to the acetabular shape in both sexes: outer acetabular profile modification, with extension from 10:00 to 1:00 and reduction from 7:00 to 9:00, acetabular notch narrowing, and acetabular fossa reduction. The age-related changes that were observed are shared by both sexes and seem to be related to bone production associated with age. Specifically, age appears to affect the entire border of the lunate surface: the acetabular rim, both acetabular horns, and the outer edge of the acetabular fossa. Furthermore, shape data confirmed the clover-leaf shape of the acetabular fossa in both males and females. These results improve our understanding of acetabular shape, and assist in refining age-estimation methods and enhancing hip surgery and rehabilitation.

New approach to age estimation of male and female adult skeletons based on the morphological characteristics of the acetabulum.

Age estimation is essential to the human identification process, both in forensic and archeological contexts. Based on the previous male-specific method of Rissech et al. (J Forensic Sci, 2006, 51:213-229), a new approach to age estimation based on the acetabulum has been described and evaluated in 611 individuals from the Lisbon Collection (Lisbon, Portugal). This paper has two main goals: (1) to revise and better define the variables of Rissech's method related to the acetabular fossa, namely, variables 5, 6, and 7, and (2) to extend the applicability of this new approach to both sexes while analyzing age-related sex differences in the acetabular aging process. The results demonstrate the suitability of combining acetabulum traits and a Bayesian approach to estimating age in adults of both sexes. This study has confirmed the usefulness of the redefined variables of the acetabular fossa when age-related changes are considered. Furthermore, the newly defined variables have good to excellent values of repeatability. The study has also extended the method's applicability to females. The revised method has absolute error averages of 7.28 years for males and 7.09 years for females, based on a sex-specific reference sample. In addition, approximately 74 % of the individuals estimated had an absolute error less than 10 years. Interestingly, the acetabular aging process follows similar trends in both sexes, but the aging rate seems to be different between males and females, especially in middle-aged individuals. Despite the fact that the age estimates, on average, did not improve significantly with the use of a sex-specific reference sample, it is recommended that the sexes be analyzed separately due to the differences in aging rates and inaccuracy values.

Ontogeny of the male femur: Geometric morphometric analysis applied to a contemporary Spanish population.

OBJECTIVE: To describe the morphological changes of the male femur during the adolescent growth spurt and to compare the pattern obtained with that reported previously for females. MATERIAL AND METHODS: Two hundred and forty males from a Spanish population aged between 9 and 16 years were analysed, based on telemetries. Size and shape variation of the femur was quantified by 22 2D-landmarks and analysed using geometric morphometric methods. Likewise, the variation of neck-shaft and bicondylar angles were also determined and evaluated by Student's t-test. Sexual differences were analysed by comparing results here obtained on boys with those corresponding to girls reported in a previous study. RESULTS: In males, both size and shape varied significantly with age, with males having larger dimensions than females. In general terms, these changes are generally characterised by an increase in robustness of the femur and shape modifications in the epiphyses. During growth, the neck-shaft angle decreases and the size of the greater and lesser trochanters increase. A significant increase of distal epiphyseal dimensions was recorded, mainly in the medial condyle. The angular remodeling of both the neck and the bicondylar regions of the male femur continues until 16 and 15 years, respectively. Female and male femur each followed divergent growth trajectories. Males showed a greater variability in neck-shaft and bicondylar angles than females. DISCUSSION: The timing, morphology and growth trajectories provided on the femur during development can be very helpful in anthropological, paleoanthropological and evolution studies.

A geometric morphometric analysis of acetabular shape of the primate hip joint in relation to locomotor behaviour.

The description of acetabular shape variation among primates is essential for our understanding of the locomotor behaviour and ecology of both extant and fossil species. In this study, we use two-dimensional geometric morphometrics to examine variation in acetabular shape in human and non-human primates and to determine the degree to which it co-varies with locomotor behaviour, while taking both intra and inter-specific variation into account. To these ends, we examined the acetabulum of 303 left hip bones of 27 extant genera of primates (including humans) with different locomotor behaviours. After accounting for shape variation due to sex, size, and phylogeny, the results confirm that acetabular shape varies significantly across locomotor groups. The two most differentiated locomotor groups are leapers and slow-climbing quadrupeds, which exhibit a unique acetabular shape. Furthermore, the acetabulum of humans differed significantly from all other groups, while no significant differences existed between chimpanzees and gorillas. The most noticeable differences are detected in both cranial and dorsal areas and around the acetabular horns. This variation in acetabular morphology may have biomechanical implications at the level of the hip joint, potentially determining joint range motion and load distribution during locomotion. Given the increasing number of published studies on fossil pelves, our results are widely applicable to fossil analyses, with critical implications for paleoanthropological analyses about the complex locomotor behaviour of fossil specimens and their classification into locomotor groups, which may enhance our understanding of their ecological habits.

Sexual dimorphism of the clavicle in a modern Spanish sample

The main objective of this study is to analyze the sexual dimorphism of the Spanish clavicle taking into account lateral asymmetry. A total of 77 adult individuals (45 males and 32 females) from the documented collection of Madrid were used. Twelve measurements were taken: four direct measurements on bone (Maximum length, midshaft circumference, sternal epiphyseal width, acromial epiphyseal width) and eight indirect measurements based on orthogonal photographic images of the clavicles placed on a light box (maximum depth of the lateral and medial curvature, angle of the lateral and medial curvature, lateral and medial curvature, area and perimeter). The asymmetry and sexual dimorphism were analyzed using Student’s t-test. Posteriorly, a PCA was applied to evaluate the contribution of each variable to sexual dimorphism. Finally, and taking into account previous results, a discriminant analysis was carried out on each clavicular side. Results indicate that the variables that contribute most in sexual dimorphism were five: perimeter, area, maximum length, midshaft circumference, and medial curvature. With them, fifteen formulae for each clavicular side were obtained: five by using individual variables and ten using combinations of two variables. The functions with highest accuracy were those constituted by two variables, specifically those comprising the midshaft circumference and the medial curvature. The obtained results and derived functions are important as they are the first to be obtained using Spanish clavicles to diagnose sex taking into account asymmetry. The new formulae are especially useful for skeletal remains from the Mediterranean area and in particular from the Iberian Peninsula

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Ontogeny of the female femur: geometric morphometric analysis applied on current living individuals of a Spanish population.

In this study we describe the development of the female femur based on the analysis of high-resolution radiographic images by means of geometric morphometrics, while assessing the usefulness of this method in these kinds of studies. The material analysed consisted of digital images in DICOM format (telemetries), corresponding to 184 left femora in anterior view, obtained from the database of the Hospital Sant Joan de Déu of Barcelona (Spain). Bones analysed corresponded to individuals from 9 to 14 years old. Size and shape variation of the entire femur was quantified by 22 two-dimensional landmarks. Landmark digitisation errors were assessed using Procrustes anova test. Centroid size (CS) variation with age was evaluated by an anova test. Shape variation was assessed by principal component analysis. A mancova test between the first five principal components and age, using the CS as covariable, was applied. Results indicated that both size and shape vary significantly with age. Several age-related shape changes remained significant after removing the allometric effect. In general, an increase in the robustness of the bone and noticeable phenotypic changes in certain areas of the femur were observed. During growth in the proximal region of the femur, the collo-diaphyseal angle decreases, the neck of the femur widens and the fovea moves to a lower position, standing more in line with the plane of the neck. Likewise, the size of the greater and lesser trochanters increase. In the distal region, a significant increase of epiphyseal dimensions was recorded, mainly in the medial condyle. The angular remodelling of the neck and the bicondylar region of the femur in females continues until 13 years old. The information provided in the present study increases our knowledge on the timing and morphology of the femur during development, and in particular the morphology of the different femoral ossification centres during development.

Humeral development from neonatal period to skeletal maturity--application in age and sex assessment.

The goal of the present study is to examine cross-sectional information on the growth of the humerus based on the analysis of four measurements, namely, diaphyseal length, transversal diameter of the proximal (metaphyseal) end of the shaft, epicondylar breadth and vertical diameter of the head. This analysis was performed in 181 individuals (90 ♂ and 91 ♀) ranging from birth to 25 years of age and belonging to three documented Western European skeletal collections (Coimbra, Lisbon and St. Bride). After testing the homogeneity of the sample, the existence of sexual differences (Student's t- and Mann-Whitney U-test) and the growth of the variables (polynomial regression) were evaluated. The results showed the presence of sexual differences in epicondylar breadth above 20 years of age and vertical diameter of the head from 15 years of age, thus indicating that these two variables may be of use in determining sex from that age onward. The growth pattern of the variables showed a continuous increase and followed first- and second-degree polynomials. However, growth of the transversal diameter of the proximal end of the shaft followed a fourth-degree polynomial. Strong correlation coefficients were identified between humeral size and age for each of the four metric variables. These results indicate that any of the humeral measurements studied herein is likely to serve as a useful means of estimating sub-adult age in forensic samples.

A collation of recently published Western European formulae for age estimation of subadult skeletal remains: recommendations for forensic anthropology and osteoarchaeology.

The aim of this study is to provide an effective and quick reference guide based on the most useful European formulae recently published for subadult age estimation. All of these formulae derive from studies on postnatal growth of the scapula, innominate, femur, and tibia, based on modern skeletal data (173 ♂, 173 ♀) from five documented collections from Spain, Portugal, and Britain. The formulae were calculated from Inverse Regression. For this reason, these formulae are especially useful for modern samples from Western Europe and in particular on 20th century human remains from the Iberian Peninsula. Eleven formulae were selected as the most useful because they can be applied to individuals from within a wide age range and in individuals of unknown sex. Due to their high reliability and because they derive from documented European skeletal samples, we recommend these formulae be used on individuals of Caucasoid ancestry from Western Europe.

Postnatal ontogenesis of the tibia. Implications for age and sex estimation.

The growth of five variables of the tibia (diaphyseal length, diaphyseal length plus distal epiphysis, condylo-malleolar length, sagittal diameter of the proximal epiphysis, maximum breadth of the distal epiphysis) were analysed using polynomial regression in order to evaluate their significance and capacity for age and sex determination during and after growth. Data were collected from 181 (90♂ and 91♀) individuals ranging from birth to 25 years of age and belonging to three documented collections from Western Europe. Results indicate that all five variables exhibit linear behaviour during growth, which can be expressed by a first-degree polynomial function. Sexual significant differences were observed from age 15 onward in the two epiphysis measurements and condylo-malleolar length, suggesting that these three variables could be useful for sex determination in individuals older than 15 years. Strong correlation coefficients were identified between the five tibial variables and age. These results indicate that any of the studied tibial measurements is likely to serve as a useful source for estimating sub-adult age in both archaeological and forensic samples.

A comparison of three established age estimation methods on an adult Spanish sample.

Most current methods for adult skeletal age-at-death estimation are based on American samples comprising individuals of European and African ancestry. Our limited understanding of population variability hampers our efforts to apply these techniques to various skeletal populations around the world, especially in global forensic contexts. Further, documented skeletal samples are rare, limiting our ability to test our techniques. The objective of this paper is to test three pelvic macroscopic methods [(1) Suchey-Brooks; (2) Lovejoy; and (3) Buckberry and Chamberlain] on a documented modern Spanish sample. These methods were selected because they are popular among Spanish anthropologists and because they never have been tested in a Spanish sample. The study sample consists of 80 individuals (55 males and 25 females) of known sex and age from the Valladolid collection. Results indicate that in all three methods, levels of bias and inaccuracy increase with age. The Lovejoy method performs poorly (27%) compared with Suchey-Brooks (71%) and Buckberry and Chamberlain (86%). However, the levels of correlation between phases and chronological ages are low and comparable in the three methods (<0.395). The apparent accuracy of the Suchey-Brooks and Buckberry and Chamberlain methods is largely based on the broad width of the methods' estimated intervals. This study suggests that before systematic application of these three methodologies in Spanish populations, further statistical modeling and research into the covariance of chronological age with morphological change are necessary. Future methods should be developed specific to various world populations and should allow for both precision and flexibility in age estimation.

Sacral fusion as an aid in age estimation.

The degree of fusion at the anterior aspect of the sacral vertebrae has been scored in 242 male and female skeletons from the Lisbon documented collection, ranging from 16 to 59 years old in age. Statistical tests indicate a sex difference towards earlier fusion in young females compared with young males, as well as a clear association between degree of fusion and age. Similar results have been found by other authors in documented skeletal samples from Coimbra and Sassari, and the recommendations stated by these authors regarding age estimation have been positively tested in the Lisbon collection. Although more research from geographically diverse samples is required, a general picture of the pattern of sacral fusion and its associations with age and sex is emerging. We also provide a practical example of the usefulness of the sacrum for age estimation in a forensic setting, a mass grave from the Spanish Civil War. It is concluded that the scoring of the degree of fusion of the sacral vertebrae, specially of S(1-2), can be a simple tool for assigning skeletons to broad age groups, and it should be implemented as another resource for age estimation in the study of human skeletal remains.