Internal Bone Structure Research Articles

Three-dimensional topology optimization model to simulate the external shapes of bone.

Elucidation of the mechanism by which the shape of bones is formed is essential for understanding vertebrate development. Bones support the body of vertebrates by withstanding external loads, such as those imposed by gravity and muscle tension. Many studies have reported that bone formation varies in response to external loads. An increased external load induces bone synthesis, whereas a decreased external load induces bone resorption. This relationship led to the hypothesis that bone shape adapts to external load. In fact, by simulating this relationship through topology optimization, the internal trabecular structure of bones can be successfully reproduced, thereby facilitating the study of bone diseases. In contrast, there have been few attempts to simulate the external structure of bones, which determines vertebrate morphology. However, the external shape of bones may be reproduced through topology optimization because cells of the same type form both the internal and external structures of bones. Here, we constructed a three-dimensional topology optimization model to attempt the reproduction of the external shape of teleost vertebrae. In teleosts, the internal structure of the vertebral bodies is invariable, exhibiting an hourglass shape, whereas the lateral structure supporting the internal structure differs among species. Based on the anatomical observations, we applied different external loads to the hourglass-shaped part. The simulations produced a variety of three-dimensional structures, some of which exhibited several structural features similar to those of actual teleost vertebrae. In addition, by adjusting the geometric parameters, such as the width of the hourglass shape, we reproduced the variation in the teleost vertebrae shapes. These results suggest that a simulation using topology optimization can successfully reproduce the external shapes of teleost vertebrae. By applying our topology optimization model to various bones of vertebrates, we can understand how the external shape of bones adapts to external loads.

Cortical and trabecular bone structure of the hominoid capitate.

Morphological variation in the hominoid capitate has been linked to differences in habitual locomotor activity due to its importance in movement and load transfer at the midcarpal joint proximally and carpometacarpal joints distally. Although the shape of bones and their articulations are linked to joint mobility, the internal structure of bones has been shown experimentally to reflect, at least in part, the loading direction and magnitude experienced by the bone. To date, it is uncertain whether locomotor differences among hominoids are reflected in the bone microarchitecture of the capitate. Here, we apply a whole‐bone methodology to quantify the cortical and trabecular architecture (separately and combined) of the capitate across bipedal (modern Homo sapiens), knuckle‐walking (Pan paniscus, Pan troglodytes, Gorilla sp.), and suspensory (Pongo sp.) hominoids (n = 69). It is hypothesized that variation in bone microarchitecture will differentiate these locomotor groups, reflecting differences in habitual postures and presumed loading force and direction. Additionally, it is hypothesized that trabecular and cortical architecture in the proximal and distal regions, as a result of being part of mechanically divergent joints proximally and distally, will differ across these portions of the capitate. Results indicate that the capitate of knuckle‐walking and suspensory hominoids is differentiated from bipedal Homo primarily by significantly thicker distal cortical bone. Knuckle‐walking taxa are further differentiated from suspensory and bipedal taxa by more isotropic trabeculae in the proximal capitate. An allometric analysis indicates that size is not a significant determinate of bone variation across hominoids, although sexual dimorphism may influence some parameters within Gorilla. Results suggest that internal trabecular and cortical bone is subjected to different forces and functional adaptation responses across the capitate (and possibly other short bones). Additionally, while separating trabecular and cortical bone is normal protocol of current whole‐bone methodologies, this study shows that when applied to carpals, removing or studying the cortical bone separately potentially obfuscates functionally relevant signals in bone structure.

Effects of thermal insult on bone tissue as observed by micro computed tomography

Abstract A thorough understanding of the effects of heat on bone morphology is required for reliable analysis of burnt skeletal remains in forensic anthropology and bioarchaeology. However, thermal damage often prevents application of the usual analytical techniques in both modern and archaeological contexts. This study uses Micro Computed Tomography (MicroCT) to assess heat-induced changes in incinerated bovine (Bos taurus) long bones at temperatures between 100 and 700 °C. Scans provided data on bone porosity and surface to volume ratio, which were compared between samples. Macroscopic comparisons were also undertaken using 3D reconstructions of samples. Results showed a decrease in porosity between unburned samples and those burned at the highest temperature (700 °C). This change was not unidirectional, with an unexpected increase at 500 °C. The lack of uniform exponential change suggests that more than one mechanism influences bone morphology in response to thermal insult. The initial significant decrease in porosity may be attributed to the loss of organic material (100–200 °C) which had the most dramatic impact on bone morphology, whereas the increase at 500°C coincides with hydroxyapatite re-crystallisation which is known to occur around this temperature. This study demonstrates that MicroCT can be readily applied to burned bone which is often fragile and difficult to examine. Additionally, unlike most microscopic techniques MicroCT is three dimensional, allowing the internal structure of the entire bone to be investigated without destruction of the sample. The changes observed in bone morphology due to heating provide valuable insight which can inform subsequent investigation and analysis of these samples.

Microstructure of the hyoid bone based on micro-computed tomography findings.

In this study, micro-CT was used to observe the microscopic anatomy of the hyoid bone, examine the variation of the trabecular bone inside the hyoid bone, and investigate the internal structure of the hyoid bone.A total of 22 hyoid bones were scanned using micro-CT. The changes in the internal bone trabeculae were assessed with 3D reconstructions, and the fine anatomical structure of the hyoid bone was further analyzed.Micro-CT images showed the microstructure of various parts of the hyoid bone. There were significant differences in total volume, bone volume, bone area, bone density, and volume fraction between the body and greater horns of the hyoid bone (P < .05), but no significant differences in the ratio of bone area/volume and bone surface density were found between the body and greater horns of the hyoid bone (P > .05). In addition, significant differences in the trabecular bone measurements, bone trabecular connectivity, and Euler number were found between the body and greater horns of the hyoid bone (P < .05). Other parameters, including bone trabecular thickness, number of trabecular bones, bone trabecular structure model index, and anisotropy of bone trabeculae, did not differ between the body and greater horns of the hyoid bone (P > .05). There was noticeably ossified healing at the joint between the body and greater horns of the hyoid bone.Micro-CT can adequately display the internal structure of the hyoid bone. The identified bone structure may help clarify the physiological function of the hyoid bone. The present findings provide a theoretical basis for further studies aimed at pathological changes due to hyoid injury in clinical and forensic medicine.

Effect of total edentulism on the internal bone structure of mandibular condyle: a preliminary study

The aim of this study was to assess the internal structure of the mandibular condyles in patients with total edentulism by applying fractal analysis on cone-beam computed tomography (CBCT) images and compare with dentate subjects. A total of 136 mandibular condyles were assessed. All CBCT images were prepared with 0.25-mm slice thickness and maximum magnification. A 64 × 64 pixel region of interest (ROI) within the trabecular bone in the center of the condyle was selected. Fractal analysis was performed using White and Rudolph's box-counting method. Control and study groups were age and gender-matched. The mean fractal dimension (FD) value of the study group was significantly lower compared to the control group (p < 0.01). In the study group, the mean FD value of the females was significantly lower than males (p = 0.01). For the control group, there was no significant difference between the genders for FD (p = 0.11). There was no significant difference between the age subgroups of the female study group and the male control group for FD (p = 0.22, p = 0.33). The mean FD value of the younger age subgroup was significantly higher compared to the older age subgroup in the female control and male study group (p = 0.03, p = 0.01). The internal bone structure of mandibular condyles in edentulous patients was found to be affected by edentulism. Fractal analysis can be used as an effective method for assessing temporomandibular joint health.

Topological optimization of 3D printed bone analog with PEKK for surgical mandibular reconstruction

PurposeThe purpose of this study was to analyze mechanical behaviors of a topologically optimized and 3D-printed mandibular bone block with polyetherketoneketone (PEKK) for surgical mandibular reconstruction. Materials and methods3D virtual mandibular models were reconstructed from cone beam computed tomography images. A proposed mandibular resection of the mandibular body (40 mm anterior-posteriorly) was segmented. Internal structure of the resected bone was designed with topological optimization. Dental implants and implant-supported crowns were integrated into the design. A second 3D virtual model was created with the same size and location of the defect but was reconstructed with a fibular graft and implant-supported crowns. The biomechanical behaviors of the two models were compared by finite element method (FEM) under the same boundary constraints and three loading locations, namely, central incisors, lower left and right side first molar areas. ResultsThe FEM results showed the maximum stresses and displacements of the topology optimized model were much lower than those of the model with fibular bone graft. The highest stress of the optimized mandibular model was located on the lower edge of the posterior border of bone analog, and fixation screws. The maximum displacement occurred at the lower edge of the proximal mandibular stump or the lower edge of the distal mandibular body on the contralateral site. Under the same three loading locations, the maximum stress of the optimized model significantly decreased by 67.9%, 71.9% and 68.6% compared to the fibular graft model. ConclusionsThe 3D printed bone analog with topological optimization is patient-specific and has advantages over the conventional fibular bone graft for surgical mandibular reconstruction. The optimized PEKK bone analog model creates more normal stress-strain trajectories than the fibular graft model and likely provides better functional and cosmetic outcomes.

A 3D journey on virtual surfaces and inner structure of ossa genitalia in Primates by means of a non-invasive imaging tool

Novel bio-imaging techniques such as micro-Computed Tomography provide an opportunity to investigate animal anatomy and morphology by overcoming limitations imposed by traditional anatomical drawings. The primate genital bones are complex anatomical structures whose occurrence in both male penis (baculum) and female clitoris (baubellum) may be difficult to assess in individual cadavers. We tested a 3-step methodological protocol, including different techniques ranging from inexpensive/simple to more expensive/sophisticated ones, by applying it to a sample of primate species, and resulting in different levels of data complexity: (1) presence/absence manual palpation method; (2) 2D X-ray plates; 3) 3D micro-CT scans. Manual palpation failed on 2 out of 23 specimens by detecting 1 false negative and 1 false positive; radiography failed once confirming the false positive, however firmly disproved by micro-CT; micro-CT analysis reported the presence of 9 bacula out of 11 male specimens and 1 baubellum out of 12 female specimens. A different baculum position was identified between strepsirrhine and haplorrhine species. We also aim to assess micro-CT as a non-invasive technique providing updated anatomical descriptions of primate ossa genitalia. Micro-CT 3D volumes showed the surface of some bones as rough, with a jagged appearance, whereas in others the surface appeared very smooth and coherent. In addition, four main types of bone internal structure were identified: 1) totally hollow; 2) hollow epiphyses and solid diaphysis with few or several channels inside; 3) totally solid with intricate Haversian channels; 4) totally solid with some channels (structure of single baubellum scanned). Ossa genitalia appeared as a living tissue having its own Haversian-like channels. The high resolution of micro-CT 3D-images of primate genital bones disclosed additional form variability to that available from genital bone 2D images of previous studies, and showed for the first time new internal and external morphological characters. Moreover, micro-CT non-invasive approach proved appropriate to recover much of scientific knowledge still hidden and often neglected in both museum specimens and primate cadavers only destined to necropsy.

Back to the beginning: Identifying lesions of diffuse idiopathic skeletal hyperostosis prior to vertebral ankylosis

ObjectiveTo better understand the pathogenesis of DISH, identifying early or pre-DISH lesions in the spine and investigating the relationship between spinal and extra-spinal manifestations of DISH. Material44 skeletonized individuals with DISH from the WM Bass Donated Skeletal Collection. MethodsFor each vertebra, location, extension, point of origin and appearance of vertebral outgrowths were recorded. The size of the enthesophytes at the olecranon process, patella and calcaneal tuberosity was measured with digital callipers. ResultsAt either end of the DISH-ankylosed segment, isolated vertical outgrowths arising from the central third of the anterior aspect of the vertebral body can usually be observed. These bone outgrowths show a well-organized external cortical layer, an internal structure of trabecular bone and usually are unaccompanied by or show minimal associated endplate degeneration. Analysis of the relationship between spinal and extra-spinal manifestations (ESM) suggests great inter-individual variability. No correlation between any ESM and the stage of spinal DISH was found. ConclusionsSmall isolated outgrowths represent the earliest stages of the spinal manifestations of DISH. The use of ESM as an indicator of DISH should be undertaken with great caution until the relationship between these two features is understood. SignificanceImproved accuracy of paleopathological diagnostic criteria of DISH. LimitationsSmall sample comprised of only individuals with DISH. Future researchmicro-CT analysis to investigate the internal structure of the spinal lesions. Analysis of extra-spinal enthesophytes in individuals with and without DISH to understand their pathogenesis and association with the spinal lesions in individuals with DISH.

Simulations Using Finite Element Method Made on a Personalized Dental System

The human skull and the maxillary bones have a very complicated architecture, determined by the outer walls, by the internal bone structures and their joining. In this paper CAD parametric software has been used to define complex virtual models. First, the mandible and jaw were defined using CT images. These images were imported into a CAD software using specific techniques and methods. These models have been finalized in SolidWorks where the virtual model of the studied system has been generated. Then, the virtual models were exported to a software for FEA simulation and prepared for every dentistry simulations. The structure of the maxillary bones contains spongy bone tissue, cortical bone tissue along with dental tissues. Each of these tissues have certain properties (elasticity, plasticity, density) assessed by flexibility. The analysis of the mechanical tension of the dental structures has been a subject of interest in recent years in order to determine the state of tension in the dental structures and to improve the mechanical strength of these structures. Such numerical techniques can give a better understanding of reactions and interactions of individual tissues. This involves a series of computational procedures to calculate stress in each element. Field variables can be interpolated by using form functions for scientific verification and validation of clinical assumptions. Various loadings have been applied to a personalized skull obtained from CT images using CAD techniques and procedures. On this system, FEM simulations were made and maps of stress, displacements and deformations were obtained that show the mechanical behavior of the maxillary dental system. Finally, important conclusions were highlighted.

Bony lesions in early tetrapods and the evolution of mineralized tissue repair

AbstractBone healing is an important survival mechanism, allowing vertebrates to recover from injury and disease. Here we describe newly recognized paleopathologies in the hindlimbs of the early tetrapodsCrassigyrinus scoticusandEoherpeton watsonifrom the early Carboniferous of Cowdenbeath, Scotland. These pathologies are among the oldest known instances of bone healing in tetrapod limb bones in the fossil record (about 325 Ma). X-ray microtomographic imaging of the internal bone structure of these lesions shows that they are characterized by a mass of trabecular bone separated from the shaft's trabeculae by a layer of cortical bone. We frame these paleopathologies in an evolutionary context, including additional data on bone healing and its pathways across extinct and extant sarcopterygians. These data allowed us to synthesize information on cell-mediated repair of bone and other mineralized tissues in all vertebrates, to reconstruct the evolutionary history of skeletal tissue repair mechanisms. We conclude that bone healing is ancestral for sarcopterygians. Furthermore, other mineralized tissues (aspidin and dentine) were also capable of healing and remodeling early in vertebrate evolution, suggesting that these repair mechanisms are synapomorphies of vertebrate mineralized tissues. The evidence for remodeling and healing in all of these tissues appears concurrently, so in addition to healing, these early vertebrates had the capacity to restore structure and strength by remodeling their skeletons. Healing appears to be an inherent property of these mineralized tissues, and its linkage to their remodeling capacity has previously been underappreciated.

Analisis gambaran radiologis suspek ameloblastoma tipe solid pada radiograf CBCT 3D

Objectives: The aim of this case report is to provide further information on the radiological features of a solid type ameloblastoma suspected on a 3D CBCT radiograph.&#x0D; Case Report: A patient came referred by a dentist for CBCT 3D radiography with suspected clinical diagnosis of a maxillary anterior dentigerous cyst. The results of the CBCT 3D radiographic examination showed a radiointermediate with a clear border on the anterior maxilla and in the right maxillary sinus accompanied by the impact of two supernumerary teeth. Radiological features of ameloblastoma generally show a multilocular radiolucent picture and have a radiopaque septa bone internal structure such as a soap bubble appearance or honey combed appearance. This case showed a clearly demarcated radiointermediate image because a solid type ameloblastoma contains tissue that is histologically formed from cells hat are follicular or plexiform and derived from the results of a degenerative process at the center of the Langerhans islands. &#x0D; Conclusion: Radiographic examination with high modality such as CBCT 3D is very important in helping to establish a diagnosis, especially for cases that sometimes show differences in the radiographs.

Alan Cyril Walker. 23 August 1938—20 November 2017

Colleagues often refer to Alan Walker as the Eric Clapton (one of the most influential musicians of the late twentieth century) of palaeoanthropology in recognition of the artistry of his science. His field discoveries filled major gaps in our knowledge of primate evolution, such as elucidating the Miocene world of Proconsul and finding the transitional ‘Black Skull’ of Australopithecus aethiopicus and the skeleton of a Homo erectus boy. In addition to discovering these remarkable fossils, Alan was essential in bringing a palaeobiological approach to the laboratory interpretation of their bony morphology. He used the relationships between form and function in living species as a baseline for understanding the past, he pioneered dental microwear analysis to infer diet and was an early-adopter of the use of microCT to explore the internal structure of primate ear bones. Beyond these scientific accomplishments, however, it was Alan's grace and generosity that truly set him apart from his peers. As the patriarch of an extensive intellectual family of students, postdocs and colleagues, Alan taught by example how to be intellectually creative, brave, meticulous, generous and kind. His legacy will long be felt in both the science and the culture of palaeoanthropology.

Optimization of Artificial Bone Internal Structure by Topology Optimization: Finite Element Analysis

Demand for artificial bone based on titanium metal is huge. The 3-D finite element analysis software is used to simulate the force of the bone model, and the internal structure of the model is optimized by the topology optimization method for material saving. The bone is scanned by computed tomography and then a normal 3-D finite element bone model is built on the computer. Based on the normal model, apply force to the model and determine the pressure distribution of the model, and then an internal structure is optimized by topology optimization method. Four basic type of bone forces which are tension, pressure, bending and torque force are applies to the bone model. The result given by the topology optimization method is a multi-layered ring structure inside the bone model, and in each layer there are certain number of pores. The artificial bone structure proposed in this paper can satisfy the basic force of the bone with using minimum of material.

Bone regeneration using three-dimensional hexahedron channel structured BCP block in rabbit calvarial defects.

The purpose of this study is to evaluate the efficacy of bone regeneration and volume maintenance of the three-dimensional (3D) structured biphasic calcium phosphate (BCP) block with porous hexahedron channels in a rabbit calvarial model. In this work, four circular defects (diameter: 8 mm) in calvarium of rabbits were randomly assigned to (1) negative control (control), (2) 3D hexahedron channel structured BCP block, (3) deproteinized bovine bone mineral particle, and (4) deproteinized porcine bone mineral particle. Animals were euthanized at 2 (n = 5) and 8 weeks (n = 5). Outcome measures included micro-computed tomography (CT) and histomorphometrical analysis. Results indicated that in micro-CT, BCP group showed the highest new bone volume with significant difference compared to control (p = 0.008) at 8 weeks. Histomorphometrically, total augmented area of BCP group was the highest with significant difference compared to control (p = 0.008) at 8 weeks. BCP group also maintained total volume of the original defect without collapsing. BCP block with 3D hexahedron channel structure seems to have favorable osteogenic and volume maintaining ability and highly porous structure might attribute to new bone formation. Further studies regarding the optimal internal structure and porosity of the BCP block bone substitute are needed. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2254-2262, 2019.

A novel experimental design for the measurement of metacarpal bone loading and deformation and fingertip force.

BackgroundMusculoskeletal and finite element modelling are often used to predict joint loading and bone strength within the human hand, but there is a lack of in vitro evidence of the force and strain experienced by hand bones.MethodsThis study presents a novel experimental setup that allows the positioning of a cadaveric digit in a variety of postures with the measurement of force and strain experienced by the third metacarpal. The setup allows for the measurement of fingertip force as well. We tested this experimental setup using three cadaveric human third digits in which the flexor tendons were loaded in two tendon pathways: (1) parallel to the metacarpal bone shaft, with bowstringing; (2) a semi-physiological condition in which the tendons were positioned closer to the bone shaft.ResultsThere is substantial variation in metacarpal net force, metacarpal strain and fingertip force between the two tendon pathways. The net force acting on the metacarpal bone is oriented palmarly in the parallel tendon condition, causing tension along the dorsum of the metacarpal shaft, while the force increases and is oriented dorsally in the semi-physiological condition, causing compression of the dorsal metacarpal shaft. Fingertip force is also greater in the semi-physiological condition, implying a more efficient grip function. Inter-individual variation is observed in the radioulnar orientation of the force experienced by the metacarpal bone, the fingertip force, and the strain patterns on the metacarpal shaft.ConclusionThis study demonstrates a new method for measuring force and strain experienced by the metacarpal, and fingertip force in cadaveric digits that can, in turn, inform computation models. Inter-individual variation in loads experienced by the third digit suggest that there are differences in joint contact and/or internal bone structure across individuals that are important to consider in clinical and evolutionary contexts.

Optimized DNA sampling of ancient bones using Computed Tomography scans.

The prevalence of contaminant microbial DNA in ancient bone samples represents the principal limiting factor for palaeogenomic studies, as it may comprise more than 99% of DNA molecules obtained. Efforts to exclude or reduce this contaminant fraction have been numerous but also variable in their success. Here, we present a simple but highly effective method to increase the relative proportion of endogenous molecules obtained from ancient bones. Using computed tomography (CT) scanning, we identify the densest region of a bone as optimal for sampling. This approach accurately identifies the densest internal regions of petrous bones, which are known to be a source of high-purity ancient DNA. For ancient long bones, CT scans reveal a high-density outermost layer, which has been routinely removed and discarded prior to DNA extraction. For almost all long bones investigated, we find that targeted sampling of this outermost layer provides an increase in endogenous DNA content over that obtained from softer, trabecular bone. This targeted sampling can produce as much as 50-fold increase in the proportion of endogenous DNA, providing a directly proportional reduction in sequencing costs for shotgun sequencing experiments. The observed increases in endogenous DNA proportion are not associated with any reduction in absolute endogenous molecule recovery. Although sampling the outermost layer can result in higher levels of human contamination, some bones were found to have more contamination associated with the internal bone structures. Our method is highly consistent, reproducible and applicable across a wide range of bone types, ages and species. We predict that this discovery will greatly extend the potential to study ancient populations and species in the genomics era.

Reconstructing Locomotor Behaviors: Cross‐sectional Property Analysis Brings More to the Story of How Earliest Euprimates Moved

As a group, modern primates demonstrate an impressive degree of ecological and behavioral flexibility. It is likely that the earliest euprimates were similarly diverse in how they moved through their environments. Attempts to reconstruct the locomotor behaviors of Eocene primates have relied heavily on comparing the external morphologies of fossilized limb bones with those of extant taxa. Though broadly informative, the application of this method may be limited by the phylogenetic constraints associated with bone length and articular surface size and shape. Alternatively, the internal structure of a long bone's diaphysis is functionally plastic during life, responding to changes in loading behaviors. Therefore, diaphyseal cross‐sectional shape analyses may provide a more accurate account of how that individual actually moved. We apply this technique to a sample of ~54.5 million year old euprimates from Vastan Lignite Mine, India. This sample of fossils falls within 2 clades of Eocene euprimates, Omomyidae and Adapoidea, and represents at least 3 described genera.Our unpaired fossil sample of 6 femora (2 Asiadapis, 2 Marcgodinotius, 2 Vastanomys) and 4 humeri (2 probable Marcgodinotius, 2 unidentified euprimates) was compared with 20 species of extant prosimians (&lt; 1 kilogram), spanning 3 locomotor classifications (leapers, slow climbers, and non‐specialists). Vastan specimens were scanned using a Nikon XT H 225 ST micro x‐ray computed tomography (CT) scanner. From these scans, diaphyseal cross‐sectional geometric properties were calculated at 50% of femoral length and 40% of humeral length (from distal end) using MomentMacro for ImageJ, which calculates polar second moment of area (J), second moments of area about the coronal (Ix) and sagittal (Iy) planes, cortical area (CA), and total subperiosteal area (TA). Each fossil was compared to the distributions of the prosimian locomotor groups for each of the cross‐sectional properties, as well as bone length and proximal articular surface areas (estimated from linear measurements).Results of structural analyses include an unusual mosaic of locomotor indicators. The relative thickness of bone cortices (CA/TA) is high in all humeri, which is best matched among modern slow climbers. Humeri are moderately long relative to humeral head articular surface area, similar to extant slow climbers and non‐specialists. Cross‐sectional shape (Ix/Iy) of femora is variable, with the adapoids (Asiadapis and Marcgodinotius) mostly grouping with leapers and non‐specialists, while the omomyids (Vastanomys) group with slow climbers, in contrast to inferences based on some other aspects of femoral articular morphology. Femoral length relative to bending rigidity (J) or femoral head surface area is moderate to high, primarily overlapping with extant leapers and non‐specialists. These results illustrate a combination of features not found in modern prosimians and may demonstrate a unique generalist regime of movement in our earliest antecedents.Support or Funding InformationNational Geographic and Leakey FoundationThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Simulating localised cellular inflammation and substrate properties in a strain energy density based bone remodelling algorithm for use in modelling trauma

Bone responds to mechanical stimulus and a range of pre-existing finite element models have been suggested to reproduce the internal physiological structure of bone. Inflammation effects are not included in these models, yet inflammation is a key component of bone repair in trauma. Therefore, a model is proposed and tested here that extends these methods to include parameters that could be considered to represent the behaviour of bone remodelling when influenced by inflammation. The proposed model regulates remodelling based on findings from recent studies into the nature of heterotopic ossification, the formation of heterotopic bone, which have revealed information about the nature of bone after high levels of trauma. These parameters include consideration of the distance from the zone of trauma, the density of mesenchymal stem cells, and substrate stiffness as a trigger for cells becoming osteogenic. The method is tested on a two-dimensional plate model and shows that the new extended algorithm can produce a range of structures depending on inputs that could be used in the future to replicate physiological scenarios.

Design of complex bone internal structure using topology optimization with perimeter control

Large facial bone loss usually requires patient-specific bone implants to restore the structural integrity and functionality that also affects the appearance of each patient. Titanium alloys (e.g., Ti-6Al-4V) are typically used in the interfacial porous coatings between the implant and the surrounding bone to promote stability. There exists a property mismatch between the two that in general leads to complications such as stress-shielding. This biomechanical discrepancy is a hurdle in the design of bone replacements. To alleviate the mismatch, the internal structure of the bone replacements should match that of the bone. Topology optimization has proven to be a good technique for designing bone replacements. However, the complex internal structure of the bone is difficult to mimic using conventional topology optimization methods without additional restrictions. In this work, the complex bone internal structure is recovered using a perimeter control based topology optimization approach. By restricting the solution space by means of the perimeter, the intricate design complexity of bones can be achieved. Three different bone regions with well-known physiological loadings are selected to illustrate the method. Additionally, we found that the target perimeter value and the pattern of the initial distribution play a vital role in obtaining the natural curvatures in the bone internal structures as well as avoiding excessive island patterns.

A change in the direction of the wound channel in the case of the combined injury inflicted by a shot from the 9.0 mm Makarov pistol

The authors present an example from the expert practice demonstrating the influence of such factors as the properties of the ammunition fired from a weapon (including its weight, size, shape, and speed) as well as the anatomical features of the body tissues being affected on the mechanism of formation of a gunshot wound in the human body. The investigation of the suicide of subject P. has demonstrated the penetrating bullet wound of the neck and the head. The entrance wound was located at the anterior neck surface and the exit one in the left half of the occipital region. The examination of the cranial bones revealed perforating fractures of the cribriform and occipital bones. A specific feature of the case under consideration was a change in the bullet direction during its passage through the cribriform bone that made up the internal osseous barrier. A result the initially vertical wound canal turned into the horizontal one within the cerebral cranium and looked on the whole like a zigzag line. The present observation confirms the possibility of a marked change in the direction of the bullet's trajectory in the cranial cavity even when a 9.0 mm bullet fired from the Makarov pistol hits a relatively soft internal bone structure.