How does thoracic scoliosis surgery affect thoracolumbar spinal flexibility and lumbar intradiscal pressure? An in vitro study confirming the importance of the rib cage.

PURPOSE: To evaluate effects of spinal and rib osteotomies on the resulting spinal flexibility for surgical correction of thoracic scoliosis and to explore effects of posterior fixation on thoracolumbar segmental range of motion and lumbar intervertebral disc loading. METHODS: Six fresh frozen human thoracolumbar spine and rib cage specimens (26-45 years, two female / four male) without clinically relevant deformity were loaded with pure moments of 5 Nm in flexion/extension, lateral bending, and axial rotation. Optical motion tracking of all segmental levels (C7-S) and intradiscal pressure measurements of the lumbar spine (L1-L5) were performed (1) in intact condition, (2) after Schwab grade 1, (3) Schwab grade 2, and (4) left rib osteotomies at T6-T10 levels, as well as (5) after posterior spinal fixation with pedicle screw-rod instrumentation at T4-L1 levels. RESULTS: Schwab grade 1 and 2 osteotomies did not significantly (p > 0.05) affect spinal flexibility, whereas left rib osteotomies significantly (p < 0.05) increased segmental ranges of motion at upper and lower levels in flexion/extension and at treated levels in lateral bending. Posterior fixation caused significantly (p < 0.05) increased range of motion at upper adjacent thoracic and mid-lumbar levels, as well as significantly (p < 0.05) increased intradiscal pressure at the lower adjacent level. CONCLUSION: Low effects of Schwab grade 1 and 2 osteotomies question the impact of isolated posterior spinal releases for surgical correction maneuvers in adolescent idiopathic scoliosis, in contrast to additional concave rib osteotomies. High effects of posterior fixation potentially explain frequently reported complications such as adjacent segment disease or proximal junctional kyphosis.

Classification of thoracic spine fractures: the four-column theory.

PURPOSE: The purpose of this study is to present a classification of thoracic spine fractures based on anatomical and biomechanical characteristics. METHODS: This is a narrative review of the literature. RESULTS: The classification is based on the relationship between movement and common forces acting on the spine. A mechanistic concept is incorporated into the classification, which considers both movements and the application of forces, leading to pathomorphological characteristics. A hierarchical ranking determines the severity of fractures within the thoracic spine, and treatment recommendations are presented in each category. The fourth column of the spine is incorporated into the classification through direct and indirect mechanisms. CONCLUSIONS: The proposed classification accommodates several advantages, such as simplicity and practicality, that make this classification helpful in daily practice. The dynamic relationship between movement and force provides a better understanding of the fracture mechanism. Finally, incorporating the fourth column will strengthen the indication for surgical management. To the best of our knowledge, this classification is the first classification developed uniquely for the thoracic spine fractures and will help to address a critical gap in the literature.

Traumatic abdominal intercostal hernia: A rare experience.

Traumatic abdominal intercostal hernias (AIHs) are an extremely rare surgical encounter, with amorphous literature. A case report of recurrent AIHs, evident only at surgery, and its management is presented. The inadequacy of experience and data translates to frequent missed diagnosis and suboptimal surgical management with high recurrence rates.

Morphological patterns of the rib cage and lung in the healthy and adolescent idiopathic scoliosis.

The morphology of the rib cage affects both the biomechanics of the upper body's musculoskeletal structure and the respiratory mechanics. This becomes particularly important when evaluating skeletal deformities, as in adolescent idiopathic scoliosis (AIS). The aim of this study was to identify morphological characteristics of the rib cage in relation to the lung in patients with non-deformed and scoliotic spines. Computed tomography data of 40 patients without any visible spinal abnormalities (healthy group) and 21 patients with AIS were obtained retrospectively. All bony structures as well as the right and left lung were reconstructed using image segmentation. Morphological parameters were calculated based on the distances between characteristic morphological landmarks. These parameters included the rib position, length, and area, the rib cage depth and width, and the rib inclination angle on either side, as well as the spinal height and length. Furthermore, we determined the left and right lung volumes, and the area of contact between the rib cage and lung. Differences between healthy and scoliotic spines were statistically analysed using the t-test for unpaired data. The rib cage of the AIS group was significantly deformed in the dorso-ventral and medio-lateral directions. The anatomical proximity of the lung to the ribs was nearly symmetrical in the healthy group. By contrast, within the AIS group, the lung covered a significantly greater area on the left side of the rib cage at large thoracic deformities. Within the levels T1-T6, no significant difference in the rib length, depth to width relationship, or area was observed between the healthy and AIS groups. Inferior to the lung (T7-T12), these parameters exhibited greater variability. The ratio between the width of the rib cage at T6 and the thoracic spinal height (T1-T12) was significantly increased within the thoracic AIS group (1.1 ± 0.08) compared with the healthy group (1.0 ± 0.05). No statistical differences were found between the lung volumes among all the groups. While the rib cage was frequently strongly deformed in the AIS group, the lung and its surrounding ribs appeared to be normally developed. The observed rib hump in AIS appeared to be formed particularly by a more ventral position of the ribs on the concave side. Furthermore, the rib cage width to spinal height ratio suggested that the spinal height of the thoracic AIS-spine is reduced. This indicates that the spine would gain its growth-related height after correcting the spinal deformity. These are the important aspects to consider in the aetiology research and orthopaedic treatment of AIS.

Thorax Dynamic Modeling and Biomechanical Analysis of Chest Breathing in Supine Lying Position.

During respiration, the expansion and contraction of the chest and abdomen are coupled with each other, presenting a complex torso movement pattern. A finite element (FE) model of chest breathing based on the HUMOS2 human body model was developed. One-dimensional muscle units with active contraction functions were incorporated into the model based on Hill's active muscle model so as to generate muscle contraction forces that can change over time. The model was validated by comparing it to the surface displacement of the chest and abdomen during respiration. Then, the mechanism of the coupled motion of the chest and abdomen was analyzed. The analyses revealed that since the abdominal wall muscles are connected to the lower edge of the rib cage through tendons, the movement of the rib cage may cause the abdominal wall muscles to be stretched in both horizontal and vertical in a supine position. The anteroposterior and the right-left diameters of the chest will increase at inspiration, while the right-left diameter of the abdomen will decrease even though the anteroposterior diameter of the abdomen increases. The external intercostal muscles at different regions had different effects on the motion of the ribs during respiration. In particular, the external intercostal muscles at the lateral region had a larger effect on pump handle movement than bucket handle movement, and the external intercostal muscles at the dorsal region had a greater influence on bucket handle movement than pump handle movement.

The rib cage: a new element in the spinopelvic chain.

INTRODUCTION: This study analyzes anatomical variations of the thoracic cage (TC) according to spinopelvic alignment, age and gender using stereoradiography in erect position. METHODS: This retrospective multicentric study analyzed computed parameters collected from free-standing position bi-planar radiographs, among healthy subjects. Collected data were: age, gender, pelvic parameters (Pelvic Incidence, Pelvic Tilt (PT) and Sacral Slope), T1-T12 Kyphosis (TK), L1-S1 Lordosis (LL), curvilinear spinal length, global TC parameters (maximum thickness and width, rib cage volume, mean Spinal Penetration Index (SPI)), 1st-10th rib parameters (absolute and relative (to the corresponding vertebra) sagittal angles). RESULTS: Totally, 256 subjects were included (140 females). Mean age was 34 (range: 8-83). Significant correlations were found between TK and TC thickness (0.3, p < 0.001) and with TC Volume (0.3, p = 0.04), as well as rib absolute sagittal angle for upper and middle ribs (0.2, p = 0.02). Conversely, a -0.3 correlation has been exhibited between SPI and TK. Similar correlations were found with LL. PT significantly correlated with TC thickness (0.4, p = 0.003), SPI (-0.3, p = 0.03), and all rib relative sagittal angles. Among global TC parameters, only thickness and SPI significantly changed after 20 years (respectively, 0.39 and -0.52, p < 0.001). Ribs relative sagittal angle showed negative correlation with age in skeletally mature subjects (p < 0.001). CONCLUSION: This study demonstrates the correlation between TC anatomy and spinopelvic parameters, confirming its part of the spinopelvic chain of balance. Indeed, higher spinal curvatures were associated with lower SPI and higher TC thickness, TC volume and rib absolute sagittal angles.

Differences in clinical and radiological features of thoracic disc herniation presenting with acute progressive myelopathy.

PURPOSE: Symptomatic thoracic disc herniation (TDH) is relatively rare, but patients with progressive myelopathy require surgical treatment without delay in diagnosis. The aim of this study was to review clinical and radiological features in patients with TDH presenting with myelopathy. METHODS: A total of 28 consecutive patients with thoracic myelopathy (Frankel grade C or worse) due to TDH who underwent surgery were divided into 3 groups based on the time for development of myelopathy (acute (< 72 h), subacute (within a few weeks), and chronic [gradually over > 1 month)] and their data were analyzed. RESULTS: The patients in the acute group were significantly younger and had a higher body mass index (BMI) compared to those in the subacute and chronic groups. Most cases of acute myelopathy were affected in the upper thoracic level, whereas all patients with subacute and chronic myelopathy had lesions in the lower thoracic level below T8-9. Interestingly, the affected thoracic level in patients with acute myelopathy matched the upper line of the sternum. The rate of acquired walking ability without assistance was only 50.0% in the acute group. CONCLUSIONS: This study suggests that TDH presenting with acute myelopathy may have different clinical and radiological features compared to those of TDH with subacute and chronic myelopathy. Upper TDH should be suspected in cases of acute myelopathy that develops with sudden-onset back pain after certain triggers in younger and higher BMI people. These affected thoracic level matched with the upper line of the sternum in each case.

Calculating the Effect of Ribs on the Focus Quality of a Therapeutic Spherical Random Phased Array.

The overlaying rib cage is a major hindrance in treating liver tumors with high intensity focused ultrasound (HIFU). The problems caused are overheating of the ribs due to its high ultrasonic absorption capability and degradation of the ultrasound intensity distribution in the target plane. In this work, a correction method based on binarized apodization and geometric ray tracing approach was employed to avoid heating the ribs. A detailed calculation of the intensity distribution in the focus plane was undertaken to quantify and avoid the effect on HIFU beam generated by a 1-MHz 256-element random phased array after the ultrasonic beam passes through the rib cage. Focusing through the ribs was simulated for 18 different idealized ribs-array configurations and 10 anatomically correct ribs-array configurations, to show the effect of width of the ribs, intercostal spacing and the relative position of ribs and array on the quality of focus, and to identify the positions that are more effective for HIFU applications in the presence of ribs. Acoustic simulations showed that for a single focus without beam steering and for the same total acoustic power, the peak intensity at the target varies from a minimum of 211 W/cm2 to a maximum of 293 W/cm2 for a nominal acoustic input power of 15 W, whereas the side lobe level varies from 0.07 Ipeak to 0.28 Ipeak and the separation between the main lobe and side lobes varies from 2.5 mm to 6.3 mm, depending on the relative positioning of the array and ribs and the beam alignment. An increase in the side lobe level was observed by increasing the distance between the array and the ribs. The parameters of focus splitting and the deterioration of focus quality caused by the ultrasonic propagation through the ribs were quantified in various possible different clinical scenarios. In addition to idealized rib topology, anatomical realistic ribs were used to determine the focus quality of the HIFU beam when the beam is steered both in axial and transverse directions and when the transducer is positioned at different depths from the rib cage.

Aesthetic Contouring of the Chest wall with Rib Resection.

BACKGROUND: In past decades, several invasive and noninvasive aesthetic procedures have been sought as a way to improve body contouring, and one may resort to uncertified and potentially dangerous procedures to achieve that goal. An example of this practice would be the resection of ribs to reduce the waist for aesthetic reasons. The objective was to check scientific evidence on the effectiveness and safety of removal of floating ribs for aesthetic purposes. METHODS: A systematic review of the literature was carried out in EMBASE/Elsevier, Cochrane, Scopus, Medline, PubMed, BVS, SciELO, OneFile, and Lilacs, throughout the period until June 2020, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. RESULTS: Fifty-six articles were found in all databases. After applying the inclusion criteria, by reading the title and abstract of the studies found, only two articles were definitively included. One addressed the possibility of removing the 7th and 8th ribs for improving body contouring in patients with an exaggerated anterior projection of the chest wall, without showing cases or surgical techniques. The other demonstrated procedures of body contouring in transgender by the removal of the 11th and 12th ribs in five of the 22 patients studied, just providing a brief description of the surgical technique used, without details. CONCLUSIONS: Despite the relevance of the theme and its popularity, there is not enough scientific evidence to support the practice, effectiveness and safety of the resection of ribs for aesthetic purposes. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Three-dimensional geometric morphometrics of thorax-pelvis covariation and its potential for predicting the thorax morphology: A case study on Kebara 2 Neandertal.

The skeletal torso is a complex structure of outstanding importance in understanding human body shape evolution, but reconstruction usually entails an element of subjectivity as researchers apply their own anatomical expertise to the process. Among different fossil reconstruction methods, 3D geometric morphometric techniques have been increasingly used in the last decades. Two-block partial least squares analysis has shown great potential for predicting missing elements by exploiting the covariation between two structures (blocks) in a reference sample: one block can be predicted from the other one based on the strength of covariation between blocks. The first aim of this study is to test whether this predictive approach can be used for predicting thorax morphologies from pelvis morphologies within adult Homo sapiens reference samples with known covariation between the thorax and the pelvis. The second aim is to apply this method to Kebara 2 Neandertal (Israel, ∼60 ka) to predict its thorax morphology using two different pelvis reconstructions as predictors. We measured 134 true landmarks, 720 curve semilandmarks, and 160 surface semilandmarks on 60 3D virtual torso models segmented from CT scans. We conducted three two-block partial least squares analyses between the thorax (block 1) and the pelvis (block 2) based on the H. sapiens reference samples after performing generalized Procrustes superimposition on each block separately. Comparisons of these predictions in full shape space by means of Procrustes distances show that the male-only predictive model yields the most reliable predictions within modern humans. In addition, Kebara 2 thorax predictions based on this model concur with the thorax morphology proposed for Neandertals. The method presented here does not aim to replace other techniques, but to rather complement them through quantitative prediction of a virtual 'scaffold' to articulate the thoracic fossil elements, thus extending the potential of missing data estimation beyond the methods proposed in previous works.

Patient-Specific 3-Dimensional Model for High-Intensity Focused Ultrasound Treatment Through the Rib Cage: A Preliminary Study.

OBJECTIVES: The purpose of this study was to develop a patient-specific 3-dimensional model for high-intensity focused ultrasound (HIFU) treatment through the rib cage using patient data. METHODS: Experimental testing to derive parameters used in defining the amount of energy and alteration needed in treatment protocols for upper abdominal disorders under the rib cage was performed. Reconstructed rib cage models based on patient data, tissue-mimicking material phantoms, and magnetic resonance imaging-guided HIFU using a multielement phased array transducer were used in the experiments. Changes in the focal temperature, acoustic power, and acoustic pressure distribution were investigated with and without the presence of the rib cage model. An ExAblate system (InSightec Ltd, Tirat Carmel, Israel) was used to sonicate phantoms by varying the target phantom or rib cage model location. RESULTS: The effect of the rib cage on the acoustic pressure distribution and acoustic power was closely related to the anatomic structures of the ribs. Thermometry revealed that heating at the focus could be controlled by changing either the power or duration of HIFU application to improve the focal temperature change. The focal temperature change was found to be related to the distance between the rib cage model and focus and the shadow area on the transducer elements covered by the rib cage model in the beam path. CONCLUSIONS: Experimental results suggest that the rib cage model is a valuable and useful tool that can provide realistic human anatomic structures and properties for evaluating the effects of the rib cage on ultrasound propagation.

Human embryonic ribs all progress through common morphological forms irrespective of their position on the axis.

BACKGROUND: We aimed to analyze the morphogenesis of all ribs from 1st to 12th rib pairs plus vertebrae to compare their differences and features according to the position along the cranial-caudal axis during the human embryonic period. RESULTS: Rib pair formation was analyzed using high-resolution digitalized imaging data (n = 29) between Carnegie stage (CS) 18 and CS23 (corresponding to ED13-14 in mouse; HH29-35 in chick). A total of 348 rib pairs, from 1st to 12th rib pairs of each sample were subjected to Procrustes and principal component (PC) analyses. PC1 and PC2 accounted for 76.3% and 16.4% (total 92.7%) of the total variance, respectively, indicating that two components mainly accounted for the change in shape. The distribution of PC1 and PC2 values for each rib showed a "fishhook-like shape" upon fitting to a quartic equation. PC1 and PC2 value position for each rib pair moved along the fitted curve according to the development. Thus, the change in PC1 and PC2 could be expressed by a single parameter using a fitted curve as a linear scale for shape. CONCLUSION: Human embryonic ribs all progress through common morphological forms irrespective of their position on the axis.

Age-related ranges of respiratory inductance plethysmography (RIP) reference values for infants and children.

The current noninvasive method for respiratory monitoring is respiratory inductance plethysmography (RIP); two bands are connected, one each to the chest and the abdomen, to measure the breathing pattern. RIP requires post hoc analysis to calculate indices such as respiratory rate, phase angle, labored breathing index, and percent of rib cage contribution to breathing. Clinical studies have provided patient RIP values and age-matched normal values, but they lack global evaluation of normative data for a wide age range of pediatric subjects. Herein, we compiled normative RIP indices from numerous studies for a large range of pediatric ages. From these data, we derived regression equations useful for computing normal RIP parameters as a function of age. The presented review will provide caregivers the ability to compare RIP data of pediatric patients against the regression analysis. This comparison will help identify patients with pulmonary complications and aid in guiding respiratory therapy.

Biplanar stereoradiography predicts pulmonary function tests in adolescent idiopathic scoliosis: a cross-sectional study.

PURPOSE: Various spinal and rib cage parameters measured from complex examinations were found to be correlated with preoperative pulmonary function tests (PFT). The aim was to investigate the relationship between preoperative rib cage parameters and PFT using biplanar stereoradiography in patients with severe adolescent idiopathic scoliosis. METHODS: Fifty-four patients, 45 girls and nine boys, aged 13.8 ± 1.2 years, with Lenke 1 or 2 thoracic scoliosis (> 50°) requiring surgical correction were prospectively included. All patients underwent preoperative PFT and low-dose biplanar X-rays. The following data were collected: forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC ratio, residual volume, slow vital capacity (SVC), total lung capacity (TLC), rib cage volume (RCV), maximum rib hump, maximum width, mean thoracic index, spinal penetration index, apical vertebral rotation, main curve Cobb angle (MCCA), T4-T12 kyphosis. The primary outcome was the relationship between rib cage parameters and PFT. The secondary outcome was the relationship between rib cage parameters and spine parameters. Data were analyzed using Spearman's rank test. A multivariable regression analysis was performed to compare PFTs and structural parameters. Significance was set at α = 0.05. RESULTS: The mean MCCA was 68.7° ± 16.7°. RCV was highly correlated with all pulmonary capacities: TLC (r = 0.76, p < 0.0001), SVC (r = 0.78, p < 0.0001) and FVC (r = 0.77, p < 0.0001). RCV had a low correlation with FEV1/FVC (r = - 0.34, p = 0.014). SPI was not correlated with any pulmonary parameters. CONCLUSION: Rib cage volume measured by biplanar stereoradiography may represent a prediction tool for PFTs. LEVEL OF EVIDENCE: Non-randomized cross-sectional study among consecutive patients, Level 2. These slides can be retrieved under Electronic Supplementary Material.

[The effect of rib cage on the dynamic response stability of the scoliotic spine].

The purpose of this study is to reveal the protective effect of rib cage on scoliotic spine by comparing the different effect of rib cage on the stability of normal spine and Lenke1 scoliotic spine. Firstly, according to X-ray computed tomography (CT) image data, four spinal finite element models (SFEMs), including normal spine without rib cage (N1), normal spine with normal rib cage (N2), scoliotic spine without rib cage (S1) and scoliotic spine with deformed rib cage (S2), from the first thoracic vertebrae to the sacral vertebrae (T1～S) were established. Secondly, the natural vibration characteristics of the four SFEMs were obtained by modal analysis. Finally, the maximum vibration amplitudes of the four SFEMs under external excitation were obtained by steady-state analysis. As shown in results, compared with N1, the maximum deformation of N2 segment T4～T6 in the X -axis (coronal axis), Y -axis (sagittal axis) and Z -axis (vertical axis) directions decreases by 38.44%, 53.80% and 33.72%, respectively. Compared with S1, the maximum deformation of S2 segment T4～T6 in the X -axis direction, Y -axis direction and Z -axis directions decreases by 44.26%, increases by 32.80% and decreases by 49.23%, respectively. As it can be seen, for normal spine, the rib cage can improve the stability of the whole spine in three directions; for the Lenke1 scoliotic spine, the rib cage can reduce the vibration of the scoliotic spine in the X -axis and Z -axis directions and improves the stability of the whole spine in the two directions, while in the Y -axis direction, for the serious severe anteversion of scoliotic spine, the deformed rib cage exacerbates the vibration of the scoliotic spine in this direction and destroys the stability of the scoliotic spine in the Y -axis direction. This study reveals the biomechanical characteristics of rib caged influence on the stability of the scoliotic spine and it has guiding significance for the study of daily protection methods and protective tools for scoliotic patients.

Over 100 years of Krapina: New insights into the Neanderthal thorax from the study of rib cross-sectional morphology.

The Krapina costal sample was studied by Gorjanovic-Kramberger in the early twentieth century. He pointed out unique features in the sample such as the rounder rib cross-section, which was recently confirmed in other Neanderthal specimens. Round rib cross-sections are characteristic of Homo ergaster, suggesting this may be plesiomorphic for Pleistocene Homo, but it is unknown whether Homo antecessor also had this rib shape. Furthermore, the influence of allometry on the cross-sectional shape of ribs is still unknown. The large costal sample from Krapina allows us to address these issues. We quantified cross-section morphology at the midshaft throughout a closed curve of one landmark and nine sliding semilandmarks in the Krapina costal remains (n = 7), as well as in other Neanderthals (n = 50), H. antecessor (n = 3) and modern humans, both fossil (n = 12) and recent (n = 160). We used principal components analysis and mean comparisons to explore interspecific differences, regression analysis to investigate allometry, and partial least squares analysis to examine covariation of cross-section shape and overall rib morphology. Neanderthal cross-sections tended to be larger than those of recent humans except for the Krapina and Tabun remains. Regarding shape, inter-group differences were found only in the diaphragmatic thorax, where Neanderthal and H. antecessor ribs were statistically significantly rounder than those of modern humans. Allometry accounted for covariation of size on shape, but the Neandertal and modern human trajectories had different slopes. While our results based on the Krapina costal sample are similar to previous findings, we also make several new insights: 1) the cross-section morphology observed in Neanderthals was probably present in H. antecessor, albeit less marked; 2) the distinct roundness of Neanderthal cross-sections is not related to size; 3) rounder cross-sections are correlated with ribs presenting less curvature in cranial view and a low degree of torsion in recent humans. These results are important for the interpretation of fragmentary Neanderthal costal remains, and the fact that the differences are marked only in the diaphragmatic thorax could have implications for breathing kinematics.

Sprengel's deformity correction by vertical scapular osteotomy in a paediatric age group: influence of rib cage abnormalities.

INTRODUCTION: Vertical scapular osteotomy (VSO) is a known procedure for Sprengel's shoulder deformity. Its surgical results in the presence of rib cage anomalies largely remain unreported. MATERIAL AND METHODS: The influence of simple and complex rib anomalies on shoulder abduction, Cavendish grade, and radiological Rigault's score following VSO was studied retrospectively in eight paediatric patients. The omovertebral bar effect on surgical outcome was also observed. RESULTS: The average age at surgery was 6.8 years. Rib anomalies were found in seven patients among which four had simple (50%) and three complex rib anomalies (37.5%). At mean post-surgery follow-up of four years, the overall average gain in shoulder abduction was 21°. In patients having either no or simple rib anomalies (n = 5), the mean pre-operative abduction and follow-up increase was more (132°; gain 28°) compared to complex rib anomalies (110°; gain 10°). The overall average pre-operative Cavendish score changed from 2.8 to 1.5. The correction was more complete in simple or no rib anomalies. The mean preoperative Rigault score was 2.25 with only a small improvement (0.38) noted in follow-up. Two patients with omovertebral bar attained good cosmetic and functional results. CONCLUSIONS: The current study was at variance with the previously published studies in terms of improved shoulder abduction following VSO especially complex rib anomalies. The omovertebral bar was not an adverse prognosticating factor.

Changes in ventilation mechanics during expiratory rib cage compression in healthy males.

[Purpose] The purpose of this study was to clarify the differences in ventilation mechanics between quiet breathing and expiratory rib cage compression, and between expiratory rib cage compression on the upper rib cage and on the lower rib cage. [Subjects and Methods] Subjects comprised 6 healthy males. Expiratory rib cage compression was performed manually by compressing the upper and lower rib cages. Changes in the lung volume, flow rate, and esophageal and gastric pressure were examined. [Results] The end expiratory lung volume was significantly lower during expiratory rib cage compression than at rest, but the end inspiratory lung volume was not significantly different. When compared with the esophageal and gastric pressures on the upper and lower rib cages at rest, the gastric pressures were significantly higher at end expiration. Lung resistance was significantly higher during expiratory rib cage compression than at rest. [Conclusion] Although expiratory rib cage compression promoted expiration and increased tidal volume, the lung volume did not increase beyond end inspiratory levels at rest. Lung resistance may increase during expiratory rib cage compression due to a decrease in lung volume. The mechanism by which expiration is promoted differed between the upper and lower rib cages.

3D geometric morphometrics of thorax variation and allometry in Hominoidea.

Ever since the seminal papers of Keith and Schultz, hominoid primate ribcages have been described as either "funnel-" or "barrel-shaped." Following this dichotomic typology, it is currently held that Homo sapiens and hylobatids (gibbons and siamangs) share a barrel-shaped ribcage and that they are more similar to each other than to the funnel-shaped thoraces of great apes (Gorilla, Pan, and Pongo). Other researchers hypothesized that thoracic width and the invagination of the thoracic spine into the thorax are related to allometry. However, analyses that take into account the complex three-dimensional (3D) shape of the ribcage are lacking. Here, we address hypotheses about thorax shape and evolution using 3D morphometrics of thoraces in anatomical connection obtained by computed tomography scans of 23 hominoid cadavers and 10 humans and examining thorax compartments composed of seven ribs (1-7 thorax) and of 11 ribs (1-11 thorax). In the 1-7 thorax analyses, the human thorax is uniquely flat because of torsion of the upper and central ribs, differing from all non-human hominoids including hylobatids. In the 1-11 thorax analyses, humans are markedly different from African great apes, with hylobatids and orangutans intermediate. In full shape space analyses, affinities between orangutans and humans on the one hand and between hylobatids and African great apes on the other are evident. Therefore, we reject the hypothesis that humans and hylobatids bear any special affinities in overall 3D thorax shape to each other. We find that larger thoraces are wider and flatter, with a more invaginated spine, supporting the allometric hypothesis. Hominoid thorax variation shows complex interactions between allometry, rib curves, torsion, and declination, and the morphology of the costo-vertebral joint and the thoracic vertebral column. When considering functional specializations alongside phylogenetic relationships, an overly simplistic dichotomy between funnel-shaped and barrel-shaped thoraces is not supported.

The costal remains of the El Sidrón Neanderthal site (Asturias, northern Spain) and their importance for understanding Neanderthal thorax morphology.

The study of the Neanderthal thorax has attracted the attention of the scientific community for more than a century. It is agreed that Neanderthals have a more capacious thorax than modern humans, but whether this was caused by a medio-lateral or an antero-posterior expansion of the thorax is still debated, and is key to understanding breathing biomechanics and body shape in Neanderthals. The fragile nature of ribs, the metameric structure of the thorax and difficulties in quantifying thorax morphology all contribute to uncertainty regarding precise aspects of Neanderthal thoracic shape. The El Sidrón site has yielded costal remains from the upper to the lower thorax, as well as several proximal rib ends (frequently missing in the Neanderthal record), which help to shed light on Neanderthal thorax shape. We compared the El Sidrón costal elements with ribs from recent modern humans as well as with fossil modern humans and other Neanderthals through traditional morphometric methods and 3D geometric morphometrics, combined with missing data estimation and virtual reconstruction (at the 1st, 5th and 11th costal levels). Our results show that Neanderthals have larger rib heads and articular tubercles than their modern human counterparts. Neanderthal 1st ribs are smaller than in modern humans, whereas 5th and 11th ribs are considerably larger. When we articulated mean ribs (size and shape) with their corresponding vertebral elements, we observed that compared to modern humans the Neanderthal thorax is medio-laterally expanded at every level, especially at T5 and T11. Therefore, in the light of evidence from the El Sidrón costal remains, we hypothesize that the volumetric expansion of the Neanderthal thorax proposed by previous authors would mainly be produced by a medio-lateral expansion of the thorax.