Increased cochlear otic capsule thickness and intracortical canal porosity in the oim mouse model of osteogenesis imperfecta.

Osteogenesis imperfecta (OI or brittle bone disease) is a group of genetic disorders of the connective tissues caused mainly by mutations in the genes encoding collagen type I. Clinical manifestations of OI include skeletal fragility, bone deformities, and severe functional disabilities, such as hearing loss. Progressive hearing loss, usually beginning in childhood, affects approximately 70% of people with OI with more than half of the cases involving the inner ear. There is no cure for OI nor a treatment to ameliorate its corresponding hearing loss, and very little is known about the properties of OI ears. In this study, we investigate the morphology of the otic capsule and the cochlea in the inner ear of the oim mouse model of OI. High-resolution 3D images of 8-week old oim and WT inner ears were acquired using synchrotron microtomography. Volumetric morphometric measurements were conducted for the otic capsule, its intracortical canal network and osteocyte lacunae, and for the cochlear spiral ducts. Our results show that the morphology of the cochlea is preserved in the oim ears at 8 weeks of age but the otic capsule has a greater cortical thickness and altered intracortical bone porosity, with a larger number and volume density of highly branched canals in the oim otic capsule. These results portray a state of compromised bone quality in the otic capsule of the oim mice that may contribute to their hearing loss.

Morphometric analyses of clavicle's nutrient foramen.

PURPOSE: Fractures of the clavicle, which has an important location and function in the upper extremity and shoulder joint, compose 10% of all fracture cases. During the osteosynthesis of clavicle fractures and in the post-operative period of patients, considering the detailed morphometric and topographic properties of the nutrient foramen of clavicle is important to avoid the disruption of arterial nutrition of the clavicle and prevent unexpected injuries. The aim of this study was to investigate the morphometric properties of the nutrient foramen of clavicle in more detail using computedtomography images. METHODS: Computed tomography images of 116 healthy individuals (56 women/60 men) who had no pathology history were included in the presented study. Computed tomography images were reconstructed three-dimensionally using free-licensed Horos v3.3.3 software. Then, distances from clavicle's nutrient foramen to sternal end, anterior and posterior edges of the clavicle were measured. Statistical analyses were completed using SPSS v21 software. RESULTS: Our results demonstrated that the nutrient foramen of clavicle was located closer to the sternal end of the clavicle. The shortest distance to the sternal edge of clavicle was measured as 3.3 cm. Analyses of gender differences indicated that statistically significant differences were in favor of men. However, topographic properties of the clavicle's nutrient foramen were not affected by age. CONCLUSION: Nutrient foramen is mostly located closer to the sternal end of clavicle. Especially during osteosynthesis of clavicle fractures at the sternal end, maintaining the arterial supply of clavicle is of great importance for increasing the post-operative life quality of patients.

Histological age-at-death estimation in white South Africans using stereology.

Various methods are available for estimating age from skeletal remains, amongst them the use of histomorphometry. It is generally argued that age estimation standards are population specific, but this in itself creates problems as the reference samples used are often not large enough and/or lack substantial representation of all age cohorts. Traditional age methods have been shown to suffer from problems such as age mimicry. This paper aims at establishing histological age-at-death standards for the white South African population by supplementing the available sample (lacking an adequate number of young adults) with another sample of European descent to avoid over-estimation of age in younger individuals caused by age mimicry. Bone microstructures related to the number of osteons and fragments, osteon size and Haversian canal size that change with advancing age were used for the development of regression formulae. A histomorphometric assessment of the anterior cortex of the femur was done using stereology for the estimation of age at death. All sections were analysed using the optical fractionator and nucleator probes. A sample of 94 bone sections (n = 50 male, n = 44 females) of white South African individuals were used. A sample of Danish individuals (n = 14 males, n = 16 females) was combined with the South African sample to create a normal age distribution for the reference sample. Single and multiple regression equations were developed after randomly selecting a hold-out sample (n = 14) for validation. Osteon size (average length, surface area and volume) showed the highest correlation with age, followed by the number of osteons and fragments per grid area. Haversian canal size showed inconsistent changes with advancing age. Using the regression equations, predicted ages were obtained for the 14 individuals. RMSE values ranged between 14 and 17 years, which we deemed acceptable.

Bone histomorphometric measures of physical activity in children from medieval England.

OBJECTIVES: Histomorphometric studies show consistent links between physical activity patterns and the microstructure underlying the size and shape of bone. Here, we adopt a combined bone approach to explore variation in microstructure of ribs and humeri related to physical activity and historical records of manual labor in skeletal samples of children (n = 175) from medieval England. The humerus reflects greater biomechanically induced microstructural variation than the rib which is used here as a control. Variation in microstructure is sought between regions in England (Canterbury, York, Newcastle), and between high- and low-status children from Canterbury. MATERIALS AND METHODS: Thin-sections were prepared from the humerus or rib and features of bone remodeling were recorded using high-resolution microscopy and image analysis software. RESULTS: The density and size of secondary osteons in the humerus differed significantly in children from Canterbury when compared to those from York and Newcastle. Among the older children, secondary osteon circularity and diameter differed significantly between higher and lower status children. DISCUSSION: By applying bone remodeling principles to the histomorphometric data, we infer that medieval children in Canterbury engaged in less physically demanding activities than children from York or Newcastle. Within Canterbury, high-status and low-status children experienced similar biomechanical loading until around 7 years of age. After this age low-status children performed activities that resulted in more habitual loading on their arm bones than the high-status children. This inferred change in physical activity is consistent with historical textual evidence that describes children entering the work force at this age.

Median Perforating Canal in Human Mandible.

Surgical interventions in the anterior region of the human mandible are associated with many complications. Some anatomical structures like the median perforating canal were discovered in mammals. Such canals may be a cause of concern that needs attention in human mandible. The purpose of the present study was to evaluate the occurrence, location, and course of median perforating canal and its associated extensions in the anterior segment of the human mandible in cone beam computed tomography scans (CBCT). Data were collected from 160 CBCT scans, and evaluated. The incidence was 23.75% for median perforating canal with wide anatomical variations concerning the related lingual and labial extensions. Median perforating canal and their associated lingual and labial foramina are frequently seen in human mandible. A thorough investigation of the symphyseal region using CBCT must be taken into account when targeting surgical intervention in this area.

3D micro structural analysis of human cortical bone in paired femoral diaphysis, femoral neck and radial diaphysis.

Human bone is known to adapt to its mechanical environment in a living body. Both its architecture and microstructure may differ between weight-bearing and non-weight-bearing bones. The aim of the current study was to analyze in three dimensions, the morphology of the multi-scale porosities on human cortical bone at different locations. Eight paired femoral diaphyses, femoral necks, and radial diaphyses were imaged using Synchrotron Radiation µCT with a 0.7 µm isotropic voxel size. The spatial resolution facilitates the investigation of the multiscale porosities of cortical bone, from the osteonal canals system down to the osteocyte lacunar system. Our results showed significant differences in the microstructural properties, regarding both osteonal canals and osteocytes lacunae, between the different anatomical locations. The radius presents significantly lower osteonal canal volume fraction and smaller osteonal canals than the femoral diaphysis or neck. Osteocytes lacunae observed in the radius are significantly different in shape than in the femur, and lacunar density is higher in the femoral neck. These results show that the radius, a non-weight-bearing bone, is significantly different in terms of its microstructure from a weight-bearing bone such as the femur. This implies that the cortical bone properties evaluated on the femoral diaphysis, the main location studied within the literature, cannot be generalized to other anatomical locations.

Brief communication: Test of a method to identify double-zonal osteon in polarized light microscopy.

OBJECTIVES: Double-zonal osteons (DZ) have been of interest in paleopathological research because they might be linked to physiological pathology. DZ are thought to be evidence of arrested osteon formation with a brief but abrupt increase in mineralization of lamellae occurring during bone remodeling. Originally identified from microradiographs as hypermineralized rings, recent studies have identified DZ from linear polarized light microscopy (PLM). However, PLM does not guarantee the adequate detection of DZ since PLM captures bone birefringence and not hyper-mineralization. Scanning electron microscopy with backscatter electrons (BSE-SEM) allows observation of DZ by detecting differences in mineralization. The purpose of this study is to investigate whether DZ, as identified by BSE-SEM, can indeed be identified with PLM. MATERIALS AND METHODS: The sample consists of an archaeological collection of adult midshaft femurs (n = 30) from St. Matthew cemetery, Quebec City (1771-1860). DZ were identified and counted independently with PLM and BSE-SEM for the same sections. Results from both methods were compared. RESULTS: Chi-square test shows that there was no significant difference between the two methods (p = 0.404). No significant bias was found on Bland-Altman analysis and Cohen's kappa shows a substantial agreement between the two methods (Κ = 0.66). PLM shows a good accuracy (sensitivity 79%, specificity 99.4%) and reliability (Positive Predictive Value: 86.71%; Negative Predictive Value: 99.45%). DISCUSSION: These findings indicate that the two methods are interchangeable. PLM, using our proposed protocol, is reliable to accurately identify DZ. We discuss how PLM and BSE-SEM that measure different features of the bone tissue can converge on the identification of DZ.

Enigma of scapular foramen and tunnels: an untold story.

PURPOSE: The study was undertaken to make a qualitative and quantitative assessment of unnamed foramen and tunnels in adult human scapulae with aid of plain and contrast radiographs. MATERIALS AND METHODS: A total of 120 dry bones, 60 each of the right and the left side were included in the study. Distribution of these foramina and tunnels was noted for their number, side, location, course and communication. Their morphometry was done using Vernier's caliper. RESULTS: Incidence of scapular foramina was 7.5% (R > L), whereas scapular tunnels were seen in 15.8% cases. Incidence of the sinuous, curved, and straight tunnels was found to be 50, 39, and 10.7% respectively. Left-sided tunnels were longer than the right ones. Plain and contrast radiographs were taken to confirm the findings. CONCLUSION: Anatomy literature describes only two scapular foramina, namely, nutrient foramen and suprascapular foramen/notch in a great zeal; occurrence of such anonymous foramina is hardly discussed. Through this study, there is an endeavor towards unfolding the mystery of scapular foramina in terms of their morphometry and distribution, the knowledge of which will aid clinicians, forensic experts, and surgeons in better diagnosis and management of clinical cases.

Differentiating human versus non-human bone by exploring the nutrient foramen: implications for forensic anthropology.

One of the roles of a forensic anthropologist is to assist medico-legal investigations in the identification of human skeletal remains. In some instances, only small fragments of bone may be present. In this study, a non-destructive novel technique is presented to distinguish between human and non-human long bones. This technique is based on the macroscopic and computed tomography (CT) analysis of nutrient foramina. The nutrient foramen of long bone diaphyses transmits the nutrient artery which provides much of the oxygen and nutrients to the bone. The nutrient foramen and its canal were analysed in six femora and humeri of human, sheep (Ovies aries) and pig (Sus scrofa) species. The location, position and direction of the nutrient foramina were measured macroscopically. The length of the canal, angle of the canal, circumference and area of the entrance of the foramen were measured from CT images. Macroscopic analysis revealed the femora nutrient foramina are more proximal, whereas humeri foramina are more distal. The human bones and sheep humerus conform to the perceived directionality, but the pig bones and sheep femur do not. Amongst the parameters measured in the CT analysis, the angle of the canal had a discriminatory power. This study shows the potential of this technique to be used independently or complementary to other methods in distinguishing between human and non-human bone in forensic anthropology.

Occurrence of osteon banding in adult human cortical bone.

OBJECTIVES: Differentiating human from nonhuman fragmented bone is often accomplished using histological methods if the observation of gross morphology proves insufficient. Linearly oriented primary and/or secondary osteonal systems, commonly referred to as osteon bands, are described as a strong indicator of nonhuman bone, particularly the occurrence of multiple bands. This phenomenon has been conventionally documented using two-dimensional (2D) histology, but such analyses are destructive and typically limited to a single cross-section. Progressive developments in high-resolution X-ray imaging, however, allow for the nondestructive three-dimensional (3D) visualization of bone microarchitecture. The primary objective of the current research was to visualize and document the occurrence of osteon banding in adult human cortical bone using high-resolution synchrotron radiation-based micro-Computed Tomography (SR micro-CT). MATERIALS AND METHODS: Synchrotron radiation-based micro-CT scanning was carried out at the Canadian Light Source (CLS) national synchrotron facility. The presence or absence of osteon banding was visualized in human skeletal elements from three adult males with representative samples from all regions of the skeleton (n = 129). If present, osteon banding was described and quantified. RESULTS: Results indicated that 23 of 129 human cortical bone specimens exhibited osteon banding, representing 18% of the sample. Linear arrangements of primary and/or secondary osteons were observed in the following skeletal elements: temporal, parietal, frontal, occipital, clavicle, mandible, femur, tibia, ulna, second metatarsal, and sacrum. DISCUSSION: The present work represents the first 3D examination of inter-element variation in osteon banding in adult human cortical bone. Findings indicate that the presence of multiple osteon bands in a single specimen is not diagnostic of nonhuman bone. As such, osteon banding categorically should not be taken as evidence of nonhuman bone in forensic and archaeological contexts.

Cone beam computed tomographic evaluation of nutrient canals and foramina in the anterior region of the mandible.

PURPOSE: To investigate the incidence and anatomical location of mandibular nutrient canals (NCs) originating from the mandibular canal using dental cone beam computed tomography (CBCT). METHODS: CBCT images from 105 patients were examined to evaluate the presence, number, diameter, and course of NCs. RESULTS: NCs and their foramina were bilaterally located in 17 (16.2 %) images. The mean diameters of NCs and foramina were 0.9 ± 0.4 (range, 0.2-3.2) mm and 0.9 ± 0.4 (0.2-2.1) mm, respectively. NCs coursed through the mandibular incisor region up to the lingual surface of the alveolar bone crest. CONCLUSION: The present study revealed the frequency and distribution of NCs using CBCT image analysis. NCs are important because surgical injury to the neurovascular bundle within these canals can lead to excessive bleeding and postoperative paresthesia. The identification of NC on CBCT images may be useful during the harvesting of bone blocks or placement of endosseous implants in the anterior region of the mandible.

Computed Tomography Findings of Mandibular Nutrient Canals.

INTRODUCTION: The purpose of this study was to assess computed tomography (CT) findings of mandibular nutrient canals using CT images. MATERIALS AND METHODS: We retrospectively analyzed the mandibular CT images of 194 consecutive patients. For image analysis such as canal prevalence, location, number, size, shape, and the CT value of nutrient foramina were determined using CT axial images of 0.5 and 3 mm slice thickness. RESULTS: We revealed that the nutrient canals were seen 94.3% in the mandible, mostly seen in the anterior region. By location, nutrient canals were particularly seen between the central and lateral incisors. The mean number of nutrient canals was 2.7. The mean diameter of the nutrient foramen between the central and lateral incisors was 1.0 mm. In about 80% of the cases, foramina between the central and lateral incisors were ovoid. The mean CT value for the nutrient foramina between the central and lateral incisors was 411 HU. DISCUSSION AND CONCLUSIONS: Mandibular nutrient canals were ovoid shape, and the mean CT value was 411 HU. By preoperative knowledge of the position and anatomy of the mandibular nutrient canals, complications such as injury to the nutrient canals can be avoided.

The long bone deformity of osteogenesis imperfecta III: analysis of structural changes carried out with scanning electron microscopic morphometry.

The wedges of the mid-diaphyseal osteotomies carried out to correct the femoral and/or tibial native deformity in type III osteogenesis imperfecta (OI III) were used to study the remodeling patterns and lamellar organization at the level of the major deformity. Histology and scanning electron microscopy (SEM) morphology showed abnormal cortical remodeling characterized by the failure to form a cylinder of compact bone with a regular marrow canal. Atypical, flattened, and large resorption lacunae with a wide resorption front on one side and systems of parallel lamellae on the opposite side were observed, resembling those formerly reported as drifting osteons. SEM morphometry documented a higher percentage of nonossified vascular/resorption area (44.3 %) in OI than in controls (13.6 %), a lower density of secondary osteons, and lower values for the parameters expressing the individual osteon size. The mean osteon total area, the mean central canal area, and the mean osteon bone area of two selected, randomized populations of secondary osteons were significantly higher (p < 0.001, p = 0.028, and p < 0.001, respectively) in control bones than in OI. The mean ossified matrix area was not significantly different, but the mean secondary osteon number and mean density were higher in controls (both p < 0.001). Osteon wedges were carried out to correct the native deformity of OI III and morphologic analysis suggested that the abnormal remodeling pattern (with "drifting osteons") may result from the altered load and tensile stresses on the deformed tubular bones.

The vascular collar of the ilium: three-dimensional evaluation of the dominant nutrient foramen.

Nutrient arteries are the predominant blood supply to endochondral bones and are particularly important during the early stages of endochondral ossification and the active growth period. These nutrient vessels traverse the periosteal shell of a developing bone to invade the disintegrating cartilage matrix and bring about endochondral bone formation. This results in the formation of a nutrient foramen which is retained as the vascular conduit between the exterior and interior of the bone. This study examined the dominant nutrient foramen of the neonatal ilium using high resolution micro-computed (micro-CT) tomography. Three-dimensional reconstruction of micro-CT data consistently demonstrated the presence of a distinctive, yet poorly reported, collar of bone extending into the trabecular cavity beyond the endosteum. This study proposes that this collar of bone may have formed in response to osteogenic signaling from approximated arterial vasculature. Additionally, it is suggested that the formation of this collar may act as a protective mechanism to the dominant nutrient vessel and as a potential biomechanical anchor for surrounding trabeculae, aiding to increase the biomechanical competency around the area of the foramen. The documentation of this osteological structure is important from a clinical perspective to prevent the misinterpretation of fracturing and pathology on plain plate radiographs and clinical computed tomography scans.

The demonstration of the number, course, and the location of nutrient artery canals of the femur by multidetector computed tomography.

PURPOSE: The aim of this study was to evaluate the number, course, width and location of nutrient artery canals of the femur by using multidetector computed tomography (MDCT). METHODS: Sixty-six adult (35 right and 31 left) dry femurs were included in this study and scanned by MDCT. Nutrient artery canals were evaluated on the multi-planar reformatted and volume rendered images which were reproduced on the basis of axial images. RESULTS: The median value of nutrient artery canals was two (minimum 1 and maximum 6). We determined that there was a negative correlation between the number of nutrient canals and the canal diameters. The outer ostia of the nutrient artery canals were most frequently located at the middle third segment of femoral diaphysis (65%). While the vast majority of the canals were showing upward courses (95%), only a few canals were having transverse (3%) or downward (2%) courses. Most encountered location of outer ostia of the canals according to linea aspera was the medial lip of the linea aspera (44%). Various variations were demonstrated in the number, course, and location of nutrient artery canals using MDCT. CONCLUSIONS: In conclusion, the knowledge of the topographic features of the nutrient artery canals may be useful in various clinical implications such as bone grafting or radiologic evaluation for the fracture lines.

Visualization of 3D osteon morphology by synchrotron radiation micro-CT.

Cortical bone histology has been the subject of scientific inquiry since the advent of the earliest microscopes. Histology - literally the study of tissue - is a field nearly synonymous with 2D thin sections. That said, progressive developments in high-resolution X-ray imaging are enabling 3D visualization to reach ever smaller structures. Micro-computed tomography (micro-CT), employing conventional X-ray sources, has become the gold standard for 3D analysis of trabecular bone and is capable of detecting the structure of vascular (osteonal) porosity in cortical bone. To date, however, direct 3D visualization of secondary osteons has eluded micro-CT based upon absorption-derived contrast. Synchrotron radiation micro-CT, through greater image quality, resolution and alternative contrast mechanisms (e.g. phase contrast), holds great potential for non-destructive 3D visualization of secondary osteons. Our objective was to demonstrate this potential and to discuss areas of bone research that can be advanced through the application of this approach. We imaged human mid-femoral cortical bone specimens derived from a 20-year-old male (Melbourne Femur Collection) at the Advanced Photon Source synchrotron (Chicago, IL, USA) using the 2BM beam line. A 60-mm distance between the target and the detector was employed to enhance visualization of internal structures through propagation phase contrast. Scan times were 1 h and images were acquired with 1.4-µm nominal isotropic resolution. Computer-aided manual segmentation and volumetric 3D rendering were employed to visualize secondary osteons and porous structures, respectively. Osteonal borders were evident via two contrast mechanisms. First, relatively new (hypomineralized) osteons were evident due to differences in X-ray attenuation relative to the surrounding bone. Second, osteon boundaries (cement lines) were delineated by phase contrast. Phase contrast also enabled the detection of soft tissue remnants within the vascular pores. The ability to discern osteon boundaries in conjunction with vascular and cellular porosity revealed a number of secondary osteon morphologies and provided a unique 3D perspective of the superimposition of secondary osteons on existing structures. Improvements in resolution and optimization of the propagation phase contrast promise to provide further improvements in structural detail in the future.

Experimental determination of the permeability in the lacunar-canalicular porosity of bone.

Permeability of the mineralized bone tissue is a critical element in understanding fluid flow occurring in the lacunar-canalicular porosity (PLC) compartment of bone and its role in bone nutrition and mechanotransduction. However, the estimation of bone permeability at the tissue level is affected by the influence of the vascular porosity in macroscopic samples containing several osteons. In this communication, both analytical and experimental approaches are proposed to estimate the lacunar-canalicular permeability in a single osteon. Data from an experimental stress-relaxation test in a single osteon are used to derive the PLC permeability by curve fitting to theoretical results from a compressible transverse isotropic poroelastic model of a porous annular disk under a ramp loading history (2007, "Compressible and Incompressible Constituents in Anisotropic Poroelasticity: The Problem of Unconfined Compression of a Disk," J. Mech. Phys. Solids, 55, pp. 161-193; 2008, "The Unconfined Compression of a Poroelastic Annular Cylindrical Disk," Mech. Mater., 40(6), pp. 507-523). The PLC tissue intrinsic permeability in the radial direction of the osteon was found to be dependent on the strain rate used and within the range of O(10(-24))-O(10(-25)). The reported values of PLC permeability are in reasonable agreement with previously reported values derived using finite element analysis (FEA) and nanoindentation approaches.

Age-related properties at the microscale affect crack propagation in cortical bone.

The increased risk for fracture with age is associated not only with reduced bone mass but also with impaired bone quality. At the microscale, bone quality is related to porosity, microstructural organization, accumulated microdamage and intrinsic material properties. However, the link between these characteristics and fracture behavior is still missing. Bone tissue has a complex structure and as age-related compositional and structural changes occur at all hierarchical length scales it is difficult to experimentally identify and discriminate the effect of each mechanism. The aim of this study was therefore to use computational models to analyze how microscale characteristics in terms of porosity, intrinsic toughness properties and microstructural organization affect the mechanical behavior of cortical bone. Tensile tests were simulated using realistic microstructural geometries based on microscopy images of human cortical bone. Crack propagation was modelled using the extended finite element method where cement lines surrounding osteons were modelled with an interface damage law to capture crack deflections along osteon boundaries. Both increased porosity and impaired material integrity resulted in straighter crack paths with cracks penetrating osteons, similar to what is seen experimentally for old cortical bone. However, only the latter predicted a more brittle failure behavior. Furthermore, the local porosity influenced the crack path more than the macroscopic porosity. In conclusion, age-related changes in cortical bone affect the crack path and the mechanical response. However, increased porosity alone was not driving damage in old bone, but instead impaired tissue integrity was required to capture brittle failure in aging bone.

Using nutrient foramina to differentiate human from non-human long bone fragments in bioarchaeology and forensic anthropology.

Long bone shaft fragments can be found isolated in archaeological and forensic contexts, such as in mass fatality incidents. When diagnostic morphological landmarks are not visible, the assessment of a human or non-human origin of a bone fragment can be challenging. Further methods need to be developed. In long bones, the presence of a nutrient foramen on fragments that do not show any diagnostic landmarks can make the assessment of the origin of the bone still possible. In this paper, human long bones were compared to those of the following species: chicken (Gallus gallus domesticus), duck (Cairina moschata), sheep (Ovis aries), pig (Sus scrofa domesticus), and deer (fallow deer, Dama dama, and roe deer, Capreolus capreolus). Macroscopic evaluation of location, direction and appearance, and micro-CT scanning in order to measure angle and shape of canal entrance, were applied in this study to differentiate human from non-human nutrient foramina on long bone shafts. Observations regarding the location and direction of nutrient foramina were proven to be different between human and non-human bones; however, these two features might not be exploitable in cases of highly fragmented bones. The foramina appearance was the most reliable for the origin identification, although the shape of the canal entrance and its angle at the cortical bone, obtained from micro-CT scans, were also useful parameters. For a correct identification of a fragment, one parameter may not be enough and it is advisable to employ as many features as possible. This research demonstrates that nutrient foramina have potential as a reliable bone feature for the distinction between human and non-human fragmented and incomplete long bones.

Histomorphometric age estimation from the femoral cortex: A test of three methods in an Australian population.

Histological methods can be used forensically to estimate age-at-death based on patterns of change in osteon shape, size, and population density, all of which result from the continuous process of bone remodelling. The present study examines the applicability of three existing histological age-at-death estimation methods as applied to an Australian population of known age and sex. Microradiographs from 50 mid-shaft femora thin sections, equally divided by sex, were obtained from the Melbourne Femur Reference Collection (MFRC); stated chronological age-at-death is 18 to 88 years. Osteon shape metrics are measured using ImageJ and the age-at-death prediction formulae of i) Singh and Gunberg, ii) Keough et al., and iii) Goliath et al. are applied. The relationship between estimated and actual age-at-death is then statistically quantified. All three formulae demonstrate pooled and sex-specific SEE values in excess of 20 years: i) pooled ±22.92 (♂±20.91, ♀±25.20); ii) ±20.79 (♂±20.96, ♀±21.05); and iii) ±35.43 (♂±32.68, ♀±38.66). When individuals under 40 years of age were excluded from the analysis, only two of the methods demonstrated increased accuracy: i) pooled ±20.87 (♂ ±17.47, ♀ ±23.70); ii) pooled ±18.21 (♂±16.51, ♀±19.90); and iii) pooled ±41.18 (♂ ±40.12, ♀ 43.05). The present study represents a preliminary investigation of the accuracy of existing histological age-at-death standards applied in an Australian population of known age.