Human Rib Research Articles

The effect of Scheuermann's kyphosis on rib cage morphology: A skeletal study

BackgroundEvolutionary changes in human rib cage morphology rendered it prone to pathologies like Scheuermann's kyphosis (SK). However, the impact of SK on rib cage morphology is unclear. PurposeThis study aimed to examine differences in rib cage morphology (e.g., ribs and sternum) between SK patients and a control group. MethodsMeasurements of the vertebral body, transverse process angle, sternum, and rib size were taken from the skeletons of SK patients (76) and a control group (96). Statistical tests were carried out to examine differences between the study and control groups and between the right and left sides. Correlations were obtained to examine the associations between the extent of the kyphosis (kyphosis angle) and rib cage variables. ResultsThe SK group yielded significantly longer and flatter ribs than the control group in both sexes. However, males had the largest differences in the 9th rib and females in the upper ribs (5-7). Inconsistency in symmetry results was found between the sexes. In summary, SK patients had a larger anteroposterior diameter in relation to the transverse diameter than the control group. Discussion and ConclusionsSK affects the morphology of the entire thorax and changes rib proportions similarly in males and females. These changes might have a role in bipedal stability and locomotion efficiency. Moreover, understanding the unique anatomy of SK patients is essential when performing an anterior release and anterior fusion operative approach. Finally, it provides insights into respiratory complications and poor prognosis related to individuals suffering from severe hyperkyphosis.

Probabilistic Finite Element Analysis of Human Rib Biomechanics: A Framework for Improved Generalizability.

In dynamic impact events, thoracic injuries often involve rib fractures, which are closely related to injury severity. Previous studies have investigated the behavior of isolated ribs under impact loading conditions, but often neglected the variability in anatomical shape and tissue material properties. In this study, we used probabilistic finite element analysis and statistical shape modeling to investigate the effect of population-wide variability in rib cortical bone tissue mechanical properties and rib shape on the biomechanical response of the rib to impact loading. Using the probabilistic finite element analysis results, a response surface model was generated to rapidly investigate the biomechanical response of an isolated rib under dynamic anterior-posterior load given the variability in rib morphometry and tissue material properties. The response surface was used to generate pre-fracture force-displacement computational corridors for the overall population and a population sub-group of older mid-sized males. When compared to the experimental data, the computational mean response had a RMSE of 4.28N (peak force 94N) and 6.11N (peak force 116N) for the overall population and sub-group respectively, whereas the normalized area metric when comparing the experimental and computational corridors ranged from 3.32% to 22.65% for the population and 10.90% to 32.81% for the sub-group. Furthermore, probabilistic sensitivities were computed in which the contribution of uncertainty and variability of the parameters of interest was quantified. The study found that rib cortical bone elastic modulus, rib morphometry and cortical thickness are the random variables that produce the largest variability in the predicted force-displacement response. The proposed framework offers a novel approach for accounting biological variability in a representative population and has the potential to improve the generalizability of findings in biomechanical studies.

Acoustic emission applied to stochastic modeling of microdamage in compact bone

Exploring the stochastic intricacies of bone microstructure is a promising way to make progress on the practical issue of bone fracture. This study investigates the fracture of human complete ribs subjected to bending and using acoustic emission (AE) for microfailure detection. As the strain increases, the number of AE signals per unit of time rises until, beyond a certain threshold, an avalanche of signals occurs, indicating the aggregation of numerous microfailures into a macroscopic fracture. Since microfailures appear randomly throughout the bending test, and given the lack of a deterministic law and the random nature of microfailures during the bending test, we opted to develop a stochastic model to account for their occurrence within the irregular and random microstructure of the cortical bone. Notable discoveries encompass the significant correlation between adjusted parameters of the stochastic model and the total number of microfailures with anthropometric variables such as age and body mass index (BMI). The progression of microfailures with strain is significantly more pronounced with age and BMI, as measured by the rate of bone deterioration. In addition, the rate of microfailures is significantly impacted by BMI alone. It is also observed that the average energy of the identified AE events adheres to a precisely defined Pareto distribution for every specimen, with the principal exponent exhibiting a significant correlation with anthropometric variables. From a mathematical standpoint, the model can be described as a double Cox stochastic and explosive (coxplosive process) model. This further provides insight into the reason why the ribs of older individuals are considerably less resilient than those of younger individuals, breaking under a considerably lower maximum strain (εmax\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\varepsilon _{\\max }$$\\end{document}).

Explaining and predicting the increased thorax injury in aged females: age and subject-specific thorax geometry coupled with improved bone constitutive models and age-specific material properties evaluated in side impact conditions.

Predicting and understanding thorax injury is fundamental for the assessment and development of safety systems to mitigate injury risk to the increasing and vulnerable aged population. While computational human models have contributed to the understanding of injury biomechanics, contemporary human body models have struggled to predict rib fractures and explain the increased incidence of injury in the aged population. The present study enhanced young and aged human body models (HBMs) by integrating a biofidelic cortical bone constitutive model and population-based bone material properties. The HBMs were evaluated using side impact sled tests assessed using chest compression and number of rib fractures. The increase in thoracic kyphosis and the associated change in rib angle with increasing age, led to increased rib torsional moment increasing the rib shear stress. Coupled with and improved cortical bone constitutive model and aged material properties, the higher resulting shear stress led to an increased number of rib fractures in the aged model. The importance of shear stress resulting from torsional load was further investigated using an isolated rib model. In contrast, HBM chest compression, a common thorax injury-associated metric, was insensitive to the aging factors studied. This study proposes an explanation for the increased incidence of thorax injury with increasing age reported in epidemiological data, and provides an enhanced understanding of human rib mechanics that will benefit assessment and design of future safety systems.

Focused shear wave beam propagation through a 3D printed human rib cage

Transient elastography (TE) is used in clinical screenings for liver fibrosis. TE generates shear wave motion in the liver by vibration of a piston at the skin. The small, flat piston in current devices radiates shear waves that diverge from the liver, resulting in low SNR and high failure rates, especially in obese patients. Our group recently introduced focused shear wave beams for TE [Cormack et al., IEEE TBME (2024)], in which vibration of a concave piston generates shear waves that converge towards the focal region, thereby increasing SNR for liver stiffness estimation. However, because piston sizes needed for efficient shear wave focusing are larger than the typical intercostal space, the rib cage that lies between the skin and the liver may cause shear wave aberration and influence stiffness measurement. Here, we present measurements of broadband focused shear wave propagation in tissue-mimicking gel in which are embedded 3D printed human ribs. Both straight elliptical rods and anatomically realistic 3D printed ribs are used as aberrators. Measurements are compared to 3D simulations of shear wave beam propagation [Archer et al., JASA (2023)]. Effects of shear wave aberration by the rib cage depend on shear wavelength, piston-to-rib distance, and piston radius and curvature.

Population trends in human rib cross-sectional shapes.

Rib fractures remain the most frequent thoracic injury in motor vehicle crashes. Computational human body models (HBMs) can be used to simulate these injuries and design mitigation strategies, but they require adequately detailed geometry to replicate such fractures. Due to a lack of rib cross-sectional shape data availability, most commercial HBMs use highly simplified rib sections extracted from a single individual during original HBM development. This study provides human rib shape data collected from chest CT scans of 240 females and males across the full adult age range. A cortical bone mapping algorithm extracted cross-sectional geometry from scans in terms of local periosteal position with respect to the central rib axis and local cortex thickness. Principal component analysis was used to reduce the dimensionality of these cross-sectional shape data. Linear regression found significant associations between principal component scores and subject demographics (sex, age, height, and weight) at all rib levels, and predicted scores were used to explore the expected rib cross-sectional shapes across a wide range of subject demographics. The resulting detailed rib cross-sectional shapes were quantified in terms of their total cross-sectional area and their cortical bone cross-sectional area. Average-sized female ribs were smaller in total cross-sectional area than average-sized male ribs by between 20% and 36% across the rib cage, with the greatest differences seen in the central portions of rib 6. This trend persisted although to smaller differences of 14%-29% when comparing females and males of equal intermediate weight and stature. Cortical bone cross-sectional areas were up to 18% smaller in females than males of equivalent height and weight but also reached parity in certain regions of the rib cage. Increased age from 25 to 80 years was associated with reductions in cortical bone cross-sectional area (up to 37% in females and 26% in males at mid-rib levels). Total cross-sectional area was also seen to reduce with age in females but to a lesser degree (of up to 17% in mid-rib regions). Similar regions saw marginal increases in total cross-sectional area for male ribs, indicating age affects rib cortex thickness moreso than overall rib cross-sectional size. Increased subject height was associated with increased rib total and cortical bone cross-sectional areas by approximately 25% and 15% increases, respectively, in mid-rib sections for a given 30 cm increase in height, although the magnitudes of these associations varied by sex and rib location. Increased weight was associated with approximately equal changes in both cortical bone and total cross-sectional areas in males. These effects were most prominent (around 25% increases for an addition of 50 kg) toward lower ribs in the rib cage and had only modest effects (less than 12% change) in ribs 2-4. Females saw greater increases with weight in total rib area compared to cortical bone area, of up to 21% at the eighth rib level. Results from this study show the expected shapes of rib cross-sections across the adult rib cage and across a broad range of demographics. This detailed geometry can be used to produce accurate rib models representing widely varying populations.

Finite element analysis and clinical study of chest wall reconstruction using carbon fiber artificial rib

Carbon fiber composites are emerging as a promising new biomaterial for chest wall reconstruction implants due to their mechanical properties and biocompatibility. This work evaluates the biomechanics of carbon fiber artificial ribs using finite element analysis and clinical implementation. Static simulations of normal breathing process show the maximum stress on the implant is only 2.83 MPa, far below the material ultimate strength of 60 MPa, indicating the excellent fit for maintaining respiratory function. Dynamic collision simulations demonstrate the artificial rib model could withstand a 4 kg rigid object impact at 2 m/s without fracture. Reconstructing the artificial rib with a human rib in the finite element analysis model increases the overall stress tolerance. The impact force required for fracture increases 48% compared to the artificial rib alone, suggesting improved strength from rib integration. Clinically, 10 of 13 patients receiving the artificial rib implants show no significant loss of pulmonary function based on spirometry tests. Based on our findings, the combined simulations and clinical results validate the strong mechanical performance and biocompatibility of the carbon fiber artificial ribs for chest wall reconstruction under static and dynamic loading while maintaining normal respiratory function.

Morphometric and Morphological Study of the First Rib in the Population of Rajasthan, India: A Cross-sectional Study

Introduction: The first rib is the shortest, most curved and atypical of all ribs. An angle is visible between the head and the tubercle at the inferior portion of the neck, which can indicate the sex of the individual when viewed in a non anatomical position. Aim: To determine the morphometric and morphological variations of the first rib in the population of Rajasthan. Materials and Methods: This cross-sectional study was conducted in the Anatomy Department of SMS Medical College, Jaipur, Rajasthan, India, from January 2023 to April 2024. A total of 90 adult human dry first ribs (45 right and 45 left) of unknown age and sex were studied. Intact right and left ribs were included, while damaged first ribs were excluded. Data were collected using a Vernier calliper and thread to measure length, height, angle, external length, internal length, shortest external length and shortest internal length. Morphological variations, such as the scalene tubercle and vascular groove, were observed. Independent samples t-tests were used to compare means between the right and left-sides and correlation analysis assessed relationships between angular orientation and anatomical dimensions. The statistical analysis was performed using Microsoft Excel 2020 and IBM Statistical Package of Social Sciences (SPSS) version 23.0. Results: The descriptive statistics for the measured variables are as follows: the mean height and length on the right-side were 6.99±3.45 cm and 26.69±2.41 cm, respectively, while on the leftside they were 7.35±2.55 cm and 26.10±2.80 cm, respectively. The angle was greater on the left-side (16.59±6.18º). Statistical analysis indicated non significant differences between all the variables of the right and left-sides (p-value >0.05), except for strong positive correlations between angle and height (Right: r-value=0.986, p-value=0.001; Left: r-value= 0.952, p-value=0.001). Conclusion: The morphometric parameters of the first rib indicate non significant differences between the right and leftsides. The strong positive correlations between angle and height have clinical significance, as they can assist in forensic and anatomical studies related to intervertical dimensions and anatomical alignment based on the angular orientation of the first rib.

Stereomicroscopic analysis of cut marks inflicted by a knife with blade damage.

Skeletal cut mark analysis provides relevant information on the general class characteristics of suspect knife. However, there is a lack of research on the influence of blade damage on cut mark analysis. This study aimed to thoroughly investigate the effects of damaged knife blades on cut marks' morphological and morphometrical characteristics. Fifteen undamaged, non-serrated knives were used to cut human ribs to make control cut marks. The knife blades were then damaged by a series of cuts on the bones. A comparison was made between the control cuts and 3 groups of cut marks inflicted by blades that had been damaged to different degrees. The results showed that the damaged blades created wider cut marks than undamaged one. Kerf morphology was likely to imitate the cuts made by the serrated blades such as an elliptical shape, a V-shaped cross-section and the presence of coarse striations. Wear-related features can affect cut mark analysis as the marks left behind by blades damaged to different degrees showed dissimilar dimensions and morphologies. The findings of this study can be applied to a forensic investigation when cut marks were caused by a knife with a damaged blade.

Improved Predictions of Human Rib Structural Properties Using Bone Mineral Content

<div>Rib fractures are associated with high rates of morbidity and mortality. Improved methods to assess rib bone quality are needed to identify at-risk populations. Quantitative computed tomography (QCT) can be used to calculate volumetric bone mineral density (vBMD) and bone mineral content (BMC), which may be related to rib fracture risk. The objective of this study was to determine if vBMD and BMC from QCT predict human rib structural properties. 127 mid-level (5th–7th) ribs were obtained from adult female (<i>n</i> = 67) and male (<i>n</i> = 60) postmortem human subjects (PMHS). Isolated rib QCT scans were performed to calculate vBMD and BMC. Each rib was subsequently tested to failure in a dynamic simulated frontal impact and structural properties, peak force (<i>F</i><sub>Peak</sub>), percent displacement (<i>δ</i><sub>Peak</sub>), linear structural stiffness (<i>K</i>), and total energy (<i>U</i><sub>Tot</sub>) were calculated. vBMD demonstrated no significant differences between sexes (<i>p</i> > 0.05); however, males had a higher BMC than females (<i>p</i> < 0.001). Further, sex-specific differences were observed in all rib structural properties except for <i>δ</i><sub>Peak</sub> (<i>p</i> > 0.05). Age had a significant relationship with both vBMD and BMC (<i>p</i> < 0.001) but only in females when separated by sex (<i>p</i> < 0.001). vBMD predicted <i>F</i><sub>Peak</sub>, <i>δ</i><sub>Peak</sub>, <i>K</i>, and <i>U</i><sub>Tot</sub> (<i>R</i><sup>2</sup> = 9.2%–30.9%, <i>p</i> < 0.05) but was not able to predict <i>δ</i><sub>Peak</sub> in males. Similarly, BMC also predicted all rib structural properties, except for <i>δ</i><sub>Peak</sub> in males, but explained more meaningful amounts of variation (<i>R</i><sup>2</sup> = 22.2%–67.7%, <i>p</i> < 0.001). When predicting rib structural properties, BMC captures sex-specific variations in bone size that are obfuscated by vBMD and contribute to the biomechanical response of the rib during mechanical loading. Incorporating BMC into assessments of injury risk may therefore provide additional insight into the multifaceted nature of rib bone quality and differential fracture resistance.</div>

How accurate are medical CT and micro-CT techniques compared to classical histology when addressing the growth of the internal rib parameters?

Rib internal anatomy and its cross-sectional morphology inform about important biomechanical or even evolutionary aspects. Classic histological studies require destructive techniques that are reprehensible depending on the case (e.g., fossils). In the last years, non-destructive CT-based methods are contributing to complementing previous knowledge without damaging the bone. Even though these methods have been proved to be useful to understand adult variation, we do not know whether these methods are useful to cover ontogenetic variation. This work compares classical histological methods with medical- and micro-CT to quantify the amount of mineral area at the rib midshaft (% Min. Ar.), a proxy for bone density. We compared cross-sections from an ontogenetic sample of 14 human first ribs ranging from perinates to adults using a) classical histology, b) HD (9-17 microns) and SD micro-CT (90 microns), and c) standard medical-CT (0.66 mm). We found that all the CT-based methods provide a larger % Min. Ar. compared to the histological techniques, but the HD micro-CT resolution is the only capable of producing results comparable to classical histology (p > 0.01), with the SD micro-CT and the medical-CT producing statistically larger results compared to classical histology (p < 0.01). In addition, it is important to state that the resolution of a standard medical-CT is not high enough to differentiate between mineral and non-mineral areas of the cross-sections for perinates and infants. These results could have important implications to avoid (when necessary) destructive techniques that are not appropriate in the case of highly valuable specimens such as fossils.

A strain rate dependent model with decreasing Young’s Modulus for cortical human bone

In the existing literature, some studies have observed an increase in the elastic modulus of human cortical bone with strain rate, which has been described as a consequence of the viscoelastic properties of the bone. However, these results contradict the findings of other studies, in which an independence or decrease of the elastic modulus with strain rate is observed, which could be explained by other non-viscoelastic mechanisms. This research studies the dynamic behavior of human cortical bone specimens and investigates their mechanical properties . A full and objective strain rate dependent model is proposed and used to describe the experimental results obtained from uniaxial tensile tests of twenty-one human rib cortical bone specimens from twelve male post mortem human subjects (average age of 68.5 ± 12.3 years). In addition, a general discussion of some families of viscoelastic models is given and the caution with which they should be used when dealing with complex materials such as bone. The main experimental finding is that in the range of strain rate analyzed (), there is a significant decrease in Young’s modulus (E ≈ 18 GPa for and E ≈ 8 GPa for ), which is not of viscoelastic origin. Moreover, the most frequently used viscoelastic models analyzed in this study predict how the elastic modulus should not vary markedly with strain rate for small strains. In fact, the observed behavior seems related to the findings of other researchers who observed that the microcraking damage depends on the strain rate in the same sense found in our work. This allows us to interpret the qualitative results as a consequence of the microcracking that takes place within the cortical bone, and not related to viscoelastic effects.

Relation between mechanical and densimetric properties to fractal dimension in human rib cortical bone

Numerous prior studies hypothesized a power-law relationship (E∝ρα) between cortical bone Young's modulus (E) and density (ρ) with an exponent 2.3≤α≤3.0, that has not been previously justified in the literature on a theoretical level. Moreover, despite the fact microstructure have been extensively studied, the material correlate of Fractal Dimension (FD) as a descriptor of bone microstructure was not clear in previous studies. This study examined the effect of mineral content and density on the mechanical properties of a large number of human rib cortical bone samples. The mechanical properties were calculated using Digital Image Correlation and uniaxial tensile tests. CT scans were used to calculate the Fractal Dimension (FD) of each specimen. For each specimen, the mineral (fmin), organic (forg) and water (fwat) weight fractions were determined. In addition, density was measured after a drying-and-ashing process. Then, Regression Analysis was employed to investigate the relationship between anthropometric variables, weight fractions, density, and FD, as well as its impact on the mechanical properties. Young's modulus exhibited a power-law relationship with an exponent of α>2.3 when using the conventional density (wet density), but α=2 when using dry density (desecated specimens). In addition, FD increases with decreasing cortical bone density. A significant relationship has been found between FD and density, whereby FD is correlated with the embedding of low density regions in cortical bone. This study provides a new insight in the exponent value of the power-law relation between Young's Modulus and density, and relates bone behavior with the fragile fracture theory in ceramic materials. Moreover, the results suggest that Fractal Dimension is related to presence of low-density regions.

Effects of loading rate, age, and morphology on the material properties of human rib trabecular bone

The material and morphometric properties of trabecular bone have been studied extensively in bones bearing significant weight, such as the appendicular long bones and spine. Less attention has been devoted to the ribs, where quantification of material properties is vital to understanding thoracic injury. The objective of this study was to quantify the compressive material properties of human rib trabecular bone and assess the effects of loading rate, age, and morphology on the material properties. Material properties were quantified via uniaxial compression tests performed on trabecular bone samples at two loading rates: 0.005 s−1 and 0.5 s−1. Morphometric parameters of each sample were quantified before testing using micro-computed tomography. Rib trabecular bone material properties were lower on average compared to trabecular bone from other anatomical locations. Morphometric parameters indicated an anisotropic structure with low connectivity and a sparser density of trabeculae in the rib compared to other locations. No significant differences in material properties were observed between the tested loading rates. Material properties were only significantly correlated with age at the 0.005 s−1 loading rate, and no morphometric parameter was significantly correlated with age. Trabecular separation and thickness were most strongly correlated with the material properties, indicating the sparser trabecular matrix likely contributed to the lower material property values compared to other sites. The novel trabecular bone material properties reported in this study can be used to improve the thoracic response and injury prediction of computational models.

Cross-sectional properties of rib geometry from an adult population.

Introduction: Human body models (HBMs) play a key role in improving modern vehicle safety systems to protect broad populations. However, their geometry is commonly derived from single individuals chosen to meet global anthropometric targets, thus their internal anatomy may not fully represent the HBM's target demographic. Past studies show sixth rib cross-sectional geometry differences between HBM ribs and population-derived ribs, and corrections to HBM ribs based on these data have improved HBM's abilities to predict rib fracture locations. Methods: We measure and report average and standard deviations (SDs) in rib cross-sectional geometric properties derived from live subject CT scans of 240 adults aged 18-90. Male and female results are given as functions of rib number and rib lengthwise position for ribs 2 through 11. Population means/SDs are reported for measures of rib total area, rib cortical bone area, and rib endosteal area, as well as inertial moment properties of these rib sections. These population corridors are compared between males and females, and against the baseline rib geometries defined in six current HBMs. Results: Total cross-sectional area results found average males ribs to be larger than those of females by between approximately 1-2 SDs depending on rib number and position, and larger in cortical bone cross-sectional area by between 0-1 SDs. Inertial moment ratios showed female ribs being between approximately 0-1 SDs more elongated than male ribs, dependent again on rib number and position. Rib cross-sectional areas from 5 of the 6 HBMs were found to be overly large along substantial portions of most ribs when compared to average population corridors. Similarly, rib aspect ratios in HBMs deviated from average population data by up to 3 SDs in regions towards sternal rib ends. Discussion: Overall, while most HBMs capture overall trends such as reductions in cross-section along shaft lengths, many also exhibit local variation that deviates from population trends. This study's results provide the first reference values for assessing the cross-sectional geometry of human ribs across a wide range of rib levels. Results also further provide clear guidelines to improve rib geometry definitions present in current HBMs in order to better represent their target demographic.

A probabilistic model for murder weapon identification using stab-marks in human ribs.

The aim of this article is to provide a scientific and statistical basis to identify the murder weapon in stabbing cases from the geometric characteristics of the stab-marks left on human ribs. For this purpose, a quantitative predictive model is developed, based on geometric measurements of the stab-mark and its location along the rib. A general method based on Bayesian inference and probabilities is used for the model development, rather than a deterministic model given its inability in certain occasions to identify the murder weapon. Following the process explained in this article to collect the stab-mark information required, the complete probabilistic model exposed attained a high accuracy in the identification of the murder weapon between two macroscopically identical blades with a microscopic alteration in one of them (more than 90% of correct identification is achieved).

Differential Cortical Volumetric Bone Mineral Density within the Human Rib

Introduction: The human rib provides a vital role in the protection of thoracic contents. Rib fractures are linked to injuries and health complications that can be fatal. Current clinical methods to assess fracture risk and bone quality are insufficient to quantify intra-element differences in bone mineral density (BMD) or to identify at-risk populations. Utilizing quantitative computed tomography (QCT) provides accurate measures of volumetric BMD (vBMD) along the length of the rib which can help delineate factors influencing differential fracture risk. Methodology: One mid-level rib was obtained from 54 post-mortem human subjects (PMHS) and scanned using QCT. Volumes of interest (VOIs) were created for sites at 30%, 50%, and 75% of rib total curve length. Mean Hounsfield units (HU) from each VOI were converted to vBMD using a scan-specific cortical phantom calibration curve. Additionally, rib and lumbar areal BMD (aBMD) were obtained from a sub-sample of 33 PMHS. Results: Significant differences in vBMD were found between all sites within the rib (p<0.01). When analyzed by sex, vBMD between the 30% and 50% site were no longer different in either males or females (p>0.05). Separating the sample into discrete age groups demonstrated the relative differences in vBMD between sites diminished with age. Further, age as a continuous variable significantly predicted rib vBMD at all sites (p<0.05), but with little practical or clinical utility (R2, 14.7- 22.8%). Similarly, only small amounts of variation in rib vBMD were explained from DXA lumbar and rib aBMD (R2 , 1.1-21.8%). Conclusions: vBMD significantly decreased from the posterior (30%) site to the anterior (75%) site within the rib which may represent adaptation to localized mechanical loading. These differences could result in differential fracture risk across the rib. As thoracic injury can be fatal, using comprehensive assessments of bone quality that accounts for variation within the rib may provide more accurate identification of at-risk populations.

Biomechanical properties of bicortical and monocortical plate fixation for rib fractures in the adolescent human rib fracture model

Purpose The technical advancement of surgical stabilization of ribs often prevents the surgeons from fixation, despite the procedure`s documented improved outcomes. The aim of this study was to evaluate a less invasive approach involving a simplified monocortical rib fixation technique. Methods Eighteen frozen human ribs obtained intraoperatively from young individuals aged 13-18 were employed for this study. First, the ribs were fractured under three-point bending, with their intrathoracic side put under tensile stress. Following this, the ChM 4.0 rib fixation system was utilized. The specimens were categorized into two groups: bicortical fixation (n=9), monocortical fixation (n=9). Subsequently, bicortical and monocortical fixation groups underwent dynamic testing over 400,000 cycles under combined sinusoidal tensile bending and torsional loading (2 N-5 N at 3Hz). In the final stage, all samples were subjected to a destructive load to failure. Results Our analysis revealed that the fixation method did not demonstrate statistically significant differences in terms of preliminary bending stiffness (p=0.379). Similarly, undergoing a course of 400,000 cycles involving combined tensile and torsional loading did not constitute a statistically significant factor affecting the monocortical and the bicortical fixation groups (p=0.894). In the monocortical fixation group, all specimens failed due to screws pulled out from the bone. In contrast, all specimens in the bicortical fixation group exhibited failure attributed to fractures occurring just behind the plate. Nonetheless, the fixation method was not a significant factor affecting bending strength (p=0.863). Conclusions The monocortial fixation could be a reasonable option among younger populations with comparable stability of fixation.

A novel simulation model for tube thoracostomy.

Tube thoracostomy is a life-saving procedure that must be performed competently and expeditiously by emergency care providers. The primary objective of this project was to develop a simple, easily-reproducible, and realistic simulation model for tube thoracostomy placement by learners of emergency medicine. This chest tube simulator utilizes two slabs of pork ribs with associated intercostal muscle and fascial planes to aid learners in identifying anatomic landmarks, palpating intercostal spaces, and performing blunt dissection in a manner that approximates human anatomy. Holes are cut on both sides of a 1.8-bushel capacity rectangular plastic clothing hamper, and rib slabs are secured to the hamper with zip ties or metal wire. A bed pillow with plastic cover is then placed inside of the plastic hamper to simulate lung tissue. The rib-hamper complex is then wrapped with cellophane or elastic compression bandages to further anchor the rib slabs and simulate skin and subcutaneous tissues. The initial cost of our thoracostomy model is approximately $50, much less than the $1,000-$3,000 cost for a commercial model. Although the hamper and pillow can be reused an indefinite number of times, the other components of our model must be replaced occasionally. Assuming a lifespan of 1,000 uses, our model costs approximately $1.78 per attempt, compared to $4.00 per attempt with the cheapest commercial mannequin system. In fact, assuming a longer useful lifespan for the mannequin does not substantially improve this comparison (e.g. $3.10 versus $1.77 per attempt for a 10,000 attempt lifespan for the commercial mannequin), largely due to the higher cost of commercial replacement skin pads when compared to the components consumed in our model with each attempt. We describe a porcine thoracostomy model that simulates the look and feel of human ribs for purposes of tube thoracostomy training, although it could also be used for thoracentesis and thoracotomy simulation. This model is relatively cheap (costing around $50) and easy to produce within a few minutes utilizing commonly-available materials. Further study is needed to determine whether an inexpensive model like ours provides the same educational value as more expensive commercial mannequin models.

Factors affecting the numerical response and fracture location of the GHBMC M50 rib in dynamic anterior-posterior loading

Rib fractures are common traumatic injuries, with links to increased morbidity and mortality. Finite element ribs from human body models have struggled to predict the force-displacement response, force and displacement at fracture, and the fracture location for isolated rib tests. In the current study, the sensitivity of a human body model rib with updated anisotropic and asymmetric material models to changes in boundary conditions, material properties, and geometry was investigated systematically to quantify contributions to response. The updated material models using uncalibrated average material properties from literature improved the force-displacement response of the model, whereas the cross-sectional geometry was the only parameter to effect fracture location. The resulting uncalibrated model with improved material models and cross-sectional geometry closely predicted experimental average force-displacement response and fracture location.