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Rib and costal cartilage fractures are the most common injuries resulting from blunt thoracic loading scenarios, including motor vehicle collisions. The costal cartilage is a cylindrical hyaline cartilage composed of two layers: a core interstitial matrix enveloped by the perichondrium. The perichondrium itself has an inner chondrogenic layer and an outer fibrous layer. The objective of this study was to evaluate the tensile material properties of human costal cartilage perichondrium at two loading rates for a range of subject demographics. Fifty-six (n=56) samples containing the fibrous layer and chondrogenic layer (i.e., two-layered samples) were fabricated from thirty-three (n=33) donors aged from 11 to 69 years of age (19 M, 14 F). Thirteen (n=13) samples without the fibrous layer (i.e., one-layered samples) were fabricated from eight (n=8) donors aged from 11 to 54 years of age (5 M, 3 F). The perichondrium was isolated from the interstitial matrix for all samples and the fibrous layer was removed for one-layered samples to assess the effect of the absence of the fibrous layer. The tissue was then stamped into a dog bone-shaped coupon and sanded down to a uniform thickness of ~1.3 mm for two-layered samples and ~1 mm for one-layered samples. The gage length of the completed coupons was marked with a black ink dot pattern to facilitate strain calculations via video tracking. The coupons were loaded axially in tension to failure at either a slow (0.005 s⁻¹) or fast (0.5 s⁻¹) target loading rate using a material testing system. The elastic modulus, ultimate stress, ultimate strain, failure stress, failure strain, and strain energy density (SED) were then calculated for each test. Material property data were compared by sample type and loading rate. Since there was no significant influence of sex on any material properties, the data were grouped together for the analysis. Modulus, ultimate stress, failure stress, and SED were found to significantly decrease with donor age at both loading rates and ultimate and failure strain also significantly decreased with donor age at the 0.5 s⁻¹ target loading rate. Failure stress in the two-layered samples was found to be greater than that of the one-layered samples at both loading rates. One-layered samples had a greater failure strain than two-layered samples at both loading rates. Perichondrium data were compared to interstitial matrix data from a previous study to further investigate the role of cartilage layer on material properties. The modulus, ultimate stress, and failure stress of costal cartilage decreased moving radially inward (greatest in two-layered perichondrium samples, least in interstitial matrix samples). The opposite was true for ultimate and failure strain, with the greatest failure strain values occurring in the interstitial matrix and the least in the two-layered perichondrium samples. The sample size of one-layered samples was too small to draw any substantial conclusions regarding age trends. This was the first study to analyze the material property trends in costal cartilage perichondrium. The results of this study can be incorporated into virtual human body models to improve the accuracy of thoracic injury prediction in the context of motor vehicle safety. / Master of Science / Motor vehicle collisions are the second leading cause of death due to unintentional injury in the United States, with rib and costal cartilage fractures being the most commonly observed injuries. The cylindrical costal cartilage connects the front of the ribs to the sternum and is composed of two layers: a core interstitial matrix enveloped by the perichondrium. The perichondrium itself has an inner chondrogenic layer and an outer fibrous layer. Virtual human body models incorporate material property data to improve their ability to predict injury risk and are frequently used among vehicle manufacturers to evaluate safety during vehicle development. Currently, models have to make simplifications and assumptions regarding the perichondrium properties, since there are no material property studies on the isolated perichondrium to date. Therefore, the purpose of this study was to quantify the tensile material properties of human costal cartilage perichondrium at two loading rates for a range of subject demographics. Dog-bone shaped coupons with either both perichondrium layers (i.e., two-layered samples) or just the chondrogenic layer (i.e., one-layered samples) were loaded to failure under tension at either a slow (0.005 s⁻¹) or fast (0.5 s⁻¹) target loading rate using a material testing system. Data were obtained for fifty-six (n=56) two-layered samples from thirty-three (n=33) donors aged from 11 to 69 years old. Data were collected for thirteen (n=13) one-layered samples from eight (n=8) donors aged from 11 to 54 years old. The elastic modulus, ultimate stress, ultimate strain, failure stress, failure strain, and strain energy density (SED) were quantified for each test. Material properties of two-layered samples decreased with increasing donor age. No trends were found with regard to donor sex. Only ultimate and failure stress of two-layered samples were significantly affected by loading rate. Perichondrium material property data were compared to interstitial matrix data from a previous study to investigate the effect of cartilage layer on costal cartilage material properties. Elastic modulus, ultimate stress, and failure stress decreased when moving inward in cartilage layers, while ultimate and failure strain increased. Overall, this is the first study to evaluate the material properties of the perichondrium and the change in material properties with cartilage layer. These data can be used to improve the accuracy of human tolerance to thoracic injury in human body models.

The objective of this study was to evaluate the effects of sex, loading rate, and age on the tensile and compressive material properties of human rib cortical bone over a wide range of subject demographics. Tension coupons were tested from sixty-one (n = 61) subjects (M = 32, F = 29) ranging in age from 17 to 99 years of age (Avg. = 56.4 +/- 26.2 yrs.). Compression samples were tested from thirty (n = 30) subjects (M = 19, F = 11) ranging in age from 18 to 95 years of age (Avg. = 49.0 +/- 23.9 yrs.). For each subject, one coupon/sample was tested to failure on a material testing system at a targeted strain rate of 0.005 strain/s, while a second coupon/sample was tested at 0.5 strain/s. A load cell was used to measure axial load for both the tension coupons and compression samples. An extensometer was used to measure displacement within the gage length of the tension coupons and a deflectometer was used to measure displacement of the compression samples. Tension data were obtained from fifty-eight (n = 58) coupons at 0.005 strain/s and fifty-eight (n = 58) coupons at 0.5 strain/s, with fifty-five (n = 55) matched pairs. Compression data were obtained from thirty (n = 30) compression samples at 0.005 strain/s and thirty (n = 30) samples at 0.5 strain/s. The elastic modulus, yield stress, yield strain, ultimate stress, elastic strain energy density (SED), plastic SED, and total SED were then calculated for each tensile and compression test. In addition, failure stress and failure strain were calculated for each tension test. There were no significant differences in the tensile material properties between sexes and no significant interactions between age and sex for either method of loading. In regard to the differences in tensile material properties with respect to loading rate, yield stress, yield strain, failure stress, ultimate stress, elastic SED, plastic SED, and total SED were significantly lower at 0.005 strain/s compared to 0.5 strain/s. All material properties were significantly lower at 0.005 strain/s compared to 0.5 strain/s in compression. Spearman correlation analyses showed that all tensile material properties had significant negative correlations with age at 0.005 strain/s except modulus. At 0.5 strain/s, all tensile material properties except yield strain had significant negative correlations with age. No significant correlations were observed in material properties with respect to advanced age in compression at either loading rate. Although the results revealed that the tensile material properties of human rib cortical bone varied significantly with respect to chronological age, the R2 values only ranged from 0.15 - 0.62, indicating that there may be other underlying variables that better account for the variance within a given population. Overall, this is the first study to analyze the effects of sex, loading rate, and age on tensile material properties of human rib cortical bone using a reasonably large sample size and the first study to test the compressive material properties of human rib cortical bone. The results of this study provide data that allows FEMs to better assess thoracic injury risk for all vehicle occupants. Additionally, this study provides the necessary data to more accurately model and assess differences in the material response of the rib cage for nearly all vehicle occupants of driving age. / Master of Science / The thorax is one of the most frequently injured body regions in motor vehicle collisions (MVCs), and severe thoracic injuries have been shown to increase mortality risk. Finite element models (FEMs) of the human body are frequently used to evaluate thoracic injury risk. However, the accuracy of these models is dependent on the biomechanical data used to validate them. Although the material properties of bone have been shown to vary with respect to age and loading rate, previous studies that have evaluated the material properties of human rib cortical bone were limited to a small number of subjects, a narrow age range, one loading rate, and one loading mode (tension). Therefore, the purpose of this study was to evaluate the effects of sex, age, and loading rate on the tensile and compressive material properties of rib cortical bone over a wide range of subject demographics. Tension coupons were tested from sixty-one (n = 61) subjects (M = 32, F = 29) ranging in age from 17 to 99 years (Avg. = 56.4 ± 26.2 years). Compression samples were tested from thirty (n = 30) subjects (M = 19, F = 11) ranging in age from 18 to 95 years (Avg. = 49.0 ± 23.9 years). For each subject, one coupon/sample was tested to failure on a material testing system at a targeted strain rate of 0.005 strain/s, while the other coupon was tested at 0.5 strain/s. A load cell was used to measure axial load for both the tension coupons and compression samples. An extensometer was used to measure displacement within the gage length of the tension coupons and a deflectometer was used to measure displacement of the compression samples. There were no significant differences in material properties between sexes and no significant interactions between age and sex for either method of loading. In regard to the differences in tensile material properties with respect to loading rate, yield stress, yield strain, failure stress, ultimate stress, elastic SED, plastic SED, and total SED were significantly lower at 0.005 strain/s compared to 0.5 strain/s. All material properties were significantly lower at 0.005 strain/s compared to 0.5 strain/s in compression. In regard to the effect of age, all tensile material properties had significant negative correlations with age at except the modulus at 0.005 strain/s and yield strain at 0.5 strain/s. No significant correlations were observed in material properties with respect to advanced age in compression at either loading rate. Overall, this is the first study to provide the tension and compression data needed to more accurately model and assess differences in the material response of the rib cage for nearly all vehicle occupants of driving age.

The purpose of this study was to develop material properties of human rib cortical bone using dynamic tension coupon testing. This study presents 117 human rib cortical bone coupon tests from six cadavers, three male and three female, ranging in age from 18 to 67 years old. The rib sections were taken from the anterior, lateral, and posterior regions on ribs 1 through 12 of each cadaver's rib cage. The cortical bone was isolated from each rib section with a low speed diamond saw, and milled into dog bone shaped tension coupons using a small computer numerical control machine. A high-rate servo-hydraulic Material Testing System equipped with a custom slack adaptor, to provide constant strain rates, was used to apply tension loads to failure at an average rate of 0.5 strains/sec. The elastic modulus, yield stress, yield strain, ultimate stress, ultimate strain, and strain energy density were determined from the resulting stress versus strain curves. The overall average of all cadaver data gives an elastic modulus of 13.9 GPa, a yield stress of 93.9 MPa, a yield strain of 0.883 %, an ultimate stress of 124.2 MPa, an ultimate strain of 2.7 %, and a strain energy density of 250.1 MPa-strain. For all cadavers, the plastic region of the stress versus strain curves was substantial and contributed approximately 60 strain % to the overall response and over 80 strain % in the tests with the 18 year old cadaver. The rib cortical bone becomes more brittle with increasing age, shown by an increase in the modulus (p < 0.01) and a decrease in peak strain (p < 0.01). In contrast to previous three-bending tests on whole rib and rib cortical bone coupons, there were no significant differences in material properties with respect to rib region or rib level. When these results are considered in conjunction with the previous three-point bending tests, there is regional variation in the structural response of the human rib cage, but this variation appears to be primarily a result of changes in the local geometry of each rib while the material properties remain nearly constant within an individual. / Master of Science

The introduction of airbags has not significantly reduced serious thoracic injury for belted occupants in frontal crashes. This thesis has investigated the effectiveness of airbags and the characteristics of residual thoracic organ injury incurred by belted occupants in vehicles equipped with airbags. This study was based on the injury outcome of over 28,000 belted front seat occupants involved in frontal collisions. Data for this analysis was extracted from National Automotive Sampling System / Crashworthiness Data System (NASS/CDS) case years 1993-2007. The use of odds ratios for comparing the effect of airbags on the occurrence of injury has shown that airbags do not significantly increase protection against head and chest injuries. Overall, the lower extremity and the upper extremity were shown to be adversely affected by airbags. The face was the only body region that was shown to benefit from the combination of seat belts and airbags as compared to seat belts alone. An investigation into the characteristics and distributions associated with thoracic organ injuries showed the heart and great vessels are the only thoracic organs that showed a significant reduction in the rate of injury with the inclusion of airbags. In vehicles with airbags, the thoracic organs are injured more frequently than the ribs. When occupants sustain thoracic organ injury, the delta-V of the crash for vehicles with and without airbags is not significantly different. The odds of serious injury to the lungs and spleen are higher for occupants in vehicles with airbags as compared to those in vehicles without airbags. Rib fracture was found to be a poor predictor of moderate to fatal thoracic organ injury. Only 31-61% of thoracic organ injuries occur with an associated rib fracture. / Master of Science

Submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, 2014. / Aim: The aim of this study was to evaluate the normal selected radiographic parameters (thoracic kyphosis (TK), anterior vertebral body height (AVBH), posterior vertebral body height (PVBH), intervertebral disc height (IVDH) and interpedicular distance (IPD)) in young to middle-aged males across the four racial groups in Durban. Participants: Eighty young to middle-aged apparently healthy males between the ages of 18-45 years from the White, Black, Indian and Coloured racial groups in Durban. Methodology: After written informed consent was acquired, all participants underwent a case history, physical examination and thoracic orthopaedic examination. An AP and lateral radiograph of the thoracic spine was then obtained. The TK, AVBH, PVBH, IVDH and IPD were assessed using methods described previously. The IBM SPSS version 20 was utilized for the data analysis. Mean, standard deviation (SD) and range are reported for the TK, AVBH, PVBH and IPD for each of the four racial groups. For the IVDH, however, the median for the respective vertebral levels is given. ANOVA testing with Bonferroni post-hoc tests were used to determine overall inter-group variations and compare each group to the other. Pearson’s correlation test was used to determine the relationship between the thoracic kyphosis and the other radiographic parameters that were assessed. Results : The mean, SD, minimum and maximum values of the thoracic kyphosis by racial group There was no significant difference in the TK among the four race groups. Significant differences (p < 0.05) were observed in the AVBH, PVBH, IVDH and IPD between the White, Black, Indian and Coloured males at various thoracic levels. Conclusion: The trends of the various radiographic parameters observed in this study support the argument that these parameters should be based on sex, age and geographic race. These values would be useful for South African spinal health care practitioners in the diagnosis and management of spinal disorders.

EFFECTS OF THORACIC SPINAL MANIPULATIVE THERAPY ON THORACIC SPINE AND SHOULDER KINEMATICS, THORACIC SPINE FLEXION/EXTENSION EXCURSION, AND PRESSURE PAIN SENSITIVITY IN PATIENTS WITH SUBACROMIAL PAIN SYNDROME By Joseph R. Kardouni, Ph.D., PT A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, at Virginia Commonwealth University. Virginia Commonwealth University, 2013. Major Director: Lori A. Michener, PhD, PT, ATC, Professor, Department of Physical Therapy In patients with shoulder pain, the use of manual therapy directed at the spine and shoulder have been reported to provide superior outcomes to exercise based interventions or usual care without the use of manual therapy. Clinical trials have also reported improved pain and disability after thoracic spinal manipulative therapy (SMT) as a stand-alone treatment for shoulder pain. Although clinical efficacy is reported for the use of thoracic SMT for the treatment of shoulder pain, the mechanisms underlying the clinical benefits are not well understood. This limits the directed use of SMT. The benefits could be due to changes in spine or shoulder motion or neurophysiologic mechanisms of pain modulation. Elucidating the mechanism of manual therapy will aid the directed use of thoracic SMT for treating patients with shoulder pain. The research described in chapters 3 and 4 was performed to assess the effects of thoracic SMT in patients with subacromial pain syndrome with regard to biomechanical changes at the thoracic spine and shoulder and effects on central and peripheral pain sensitivity. Subjects with shoulder impingement pain symptoms were randomly assigned to receive 1 visit of thoracic SMT or sham SMT, applied to the lower, middle, and upper (cervicothoracic junction) thoracic spine. A 3-dimensional electromagnetic tracking system was used to measure thoracic and scapular kinematics during active arm elevation, and thoracic excursion at end-range of flexion and extension pre- post-treatment. Pressure pain threshold (PPT) was measured at the painful shoulder (deltoid) and unaffected regions (contralateral deltoid and bilateral lower trapezius areas) immediately pre- and post-treatment. PPT measures at the painful shoulder were used to assess peripheral and/or central pain sensitivity, and PPT at unaffected regions measured central pain sensitivity. Patient-rated outcomes measures of pain (Numeric Pain Rating Scale-NPRS), function (Pennsylvania Shoulder Score-Penn), and global rating of change (GROC) were used to assess changes in clinical symptoms following treatment. No significant differences were found between treatment groups for the thoracic kinematics or excursion, shoulder kinematics, PPT measures, or patient-rated outcomes. No differences were noted pre- to post-treatment in either group for thoracic kinematics or excursion or PPT measures. In both groups, there was a decrease in mean scapular external rotation over time during ascending arm elevation, but the change was less than measurement error. Outcome measures of NPRS, Penn and GROC indicated clinical improvements in both groups following treatment, but there were no differences between the thoracic SMT or sham SMT groups. There were no meaningful correlations between thoracic and scapular kinematics or thoracic excursion with the outcome measures of NPRS, Penn, or GROC. There was a significant positive correlation (r=0.52 , p=0.009) between change in PPT at the lower trapezius on the unaffected side and baseline Penn scores. Biomechanically, thoracic spine extension and excursion did not change following thoracic SMT, and the SMT group had no greater changes in shoulder kinematics or patient-rated pain and function than the sham SMT group. Additionally, thoracic SMT did not improve peripheral or central pain sensitivity as measured by PPT. Furthermore, improvements in patient-rated outcomes were not found to be related to changes in thoracic spine mobility, or shoulder kinematics with SMT. The single correlation between change in PPT and baseline Penn may indicate a neurophyciologic effect of SMT in patients with higher baseline function scores, but the since no other significant relationships between PPT and outcome were seen, the implications of this finding are limited. Overall, alterations in thoracic spine mobility and pressure pain sensitivity do not appear to be responsible for improved outcomes in patients with subacromial pain syndrome. Future studies should explore the effects of SMT using other measures of thoracic spine motion and experimental pain modalities, as well as greater dosing of SMT over a longer follow-up.

Thesis (Ph. D.)--University of Missouri-Columbia, 2006. / Title from title screen of research.pdf file (viewed on December 22, 2006). The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Vita. "May 2006" Includes bibliographical references.