Rib Morphology Research Articles

External rib structure can be predicted using mathematical models: An anatomical study with application to understanding fractures and intercostal muscle function.

As ribs adapt to stress like all bones, and the chest behaves as a pressure vessel, the effect of stress on the ribs can be determined by measuring rib height and thickness. Rib height and thickness (depth) were measured using CT scans of seven rib cages from anonymized cadavers. A Finite Element Analysis (FEA) model of a rib cage was constructed using a validated approach and used to calculate intramuscular forces as the vectors of both circumferential and axial chest wall forces at right angles to the ribs. Nonlinear quadratic models were used to relate rib height and rib thickness to rib level, and intercostal muscle force to vector stress. Intercostal muscle force was also related to vector stress using Pearson correlation. For comparison, rib height and thickness were measured on CT scans of children. Rib height increased with rib level, increasing by 13% between the 3rd and 7th rib levels, where the 7th/8th rib was the widest part or "equator" of the rib cage, P < 0.001 (t-test). Rib thickness showed a statistically significant 23% increase between the 3rd and 7th ribs, P = 0.004 (t-test). Intercostal muscle force was significantly related to vector stress, Pearson correlation r = 0.944, P = 0.005. The three nonlinear quadratic models developed all had statistically significant parameter estimates with P < 0.03. External rib morphology, in particular rib height and thickness, can be predicted using statistical mathematical models. Rib height is significantly related to the calculated intercostal muscle force, showing that environmental factors affect external rib morphology.

An Early Triassic Ichthyopterygian Fossil from the Osawa Formation in Minamisanriku Town, Miyagi Prefecture, Japan

The ichthyopterygian Utatsusaurus hataii Shikama et al. 1978 is the only valid reptilian taxon known from the Lower Triassic Osawa Formation in Minamisanriku Town, Miyagi Prefecture, which records the recovery of the marine ecosystem shortly after the end-Permian mass extinction. In this paper, we describe a fragmentary specimen of an indeterminate ichthyopterygian which is distinguished from Utatsusaurus hataii based on rib morphology. The discovery of a previously unknown ichthyopterygian implies that the taxonomic diversity of the reptilian fauna of this formation is higher than previously assumed.

Morphometric analysis of variation in the ribs with age and sex.

Rib cage morphology changes with age and sex are expected to affect thoracic injury mechanisms and tolerance, particularly for vulnerable populations such as pediatrics and the elderly. The size and shape variation of the external geometry of the ribs was characterized for males and females aged 0-100years. Computed tomography (CT) scans from 339 subjects were analyzed to collect between 2700 and 10400 homologous landmarks from each rib. Rib landmarks were analyzed using the geometric morphometric technique known as Procrustes superimposition. Age- and sex-specific functions of 3D rib morphology were produced representing the combined size and shape variation and the isolated shape variation. Statistically significant changes in the size and shape variation (P<0.0001) and shape variation (P<0.0053) of all 24 ribs were found to occur with age in males and females. Rib geometry, location, and orientation varied according to the rib level. From birth through adolescence, the rib cage experienced an increase in size, a decrease in thoracic kyphosis, and inferior rotation of the ribs relative to the spine within the sagittal plane. From young adulthood into elderly age, the rib cage experienced increased thoracic kyphosis and superior rotation of the ribs relative to the spine within the sagittal plane. The increased roundedness of the rib cage and horizontal angling of the ribs relative to the spine with age influences the biomechanical response of the thorax. With the plane of the rib oriented more horizontally, loading applied in the anterior-posterior direction will result in increased deformation within the plane of the rib and an increased risk for rib fractures. Thus, morphological changes may be a contributing factor to the increased incidence of rib fractures in the elderly. The morphological functions derived in this study capture substantially more information on thoracic skeleton morphology variation with age and sex than is currently available in the literature. The developed models of rib cage anatomy can be used to study age and sex variations in thoracic injury patterns due to motor vehicle crashes or falls, and clinically relevant changes due to chronic obstructive pulmonary disease or other diseases evidenced by structural and anatomic changes to the chest.

Anti-wear properties of the molluscan shell Scapharca subcrenata: Influence of surface morphology, structure and organic material on the elementary wear process

As a typical natural biological mineralisation material, molluscan shells have excellent wear-resistance properties that result from the interactions amongst biological coupling elements such as morphology, structure and material. The in-depth study of the wear-resistance performance of shells and the contribution made by each coupling element may help to promote the development of new bionic wear-resistant devices. The objective of this study was to investigate the influence of surface morphology (rib distribution on the shell), structure (rib coupled with nodules) and material (organic matter) on the anti-wear performance of the molluscan Scapharca subcrenata shell. The effect and contribution of each of these biological coupling elements were systematically investigated using the comparative experiment method. All three were found to exert significant effects on the shell's wear-resistance ability, and their individual contributions to that ability were revealed. Organic material can be classified as the principal coupling element, rib morphology as the secondary coupling element and the combined rib-nodule structure as the general coupling element.

The Biomimetic Shark Skin Optimization Design Method for Improving Lubrication Effect of Engineering Surface.

Nature has long been an important source of inspiration for mankind to develop artificial ways to mimic the remarkable properties of biological systems. In this work, a new method was explored to fabricate a biomimetic engineering surface comprising both the shark-skin, the shark body denticle, and rib morphology. It can help reduce water resistance and the friction contact area as well as accommodate lubricant. The lubrication theory model was established to predict the effect of geometric parameters of a biomimetic surface on tribological performance. The model has been proved to be feasible to predict tribological performance by the experimental results. The model was then used to investigate the effect of the grid textured surface on frictional performance of different geometries. The investigation was aimed at providing a rule for deriving the design parameters of a biomimetic surface with good lubrication characteristics. Results suggest that: (i) the increase in depression width ratio [Formula: see text] decreases its corresponding coefficient of friction, and (ii) the small coefficient of friction is achievable when [Formula: see text] is beyond 0.45. Superposition of depth ratio Γ and angle's couple under the condition of [Formula: see text] < 0.45 affects the value of friction coefficient. It shows the decrease in angle decreases with the increase in dimension depth [Formula: see text].

Effects and mechanisms of surface topography on the antiwear properties of molluscan shells (Scapharca subcrenata) using the fluid-solid interaction method.

The surface topography (surface morphology and structure) of the left Scapharca subcrenata shell differs from that of its right shell. This phenomenon is closely related to antiwear capabilities. The objective of this study is to investigate the effects and mechanisms of surface topography on the antiwear properties of Scapharca subcrenata shells. Two models are constructed—a rib morphology model (RMM) and a coupled structure model (CSM)—to mimic the topographies of the right and left shells. The antiwear performance and mechanisms of the two models are studied using the fluid-solid interaction (FSI) method. The simulation results show that the antiwear capabilities of the CSM are superior to those of the RMM. The CSM is also more conducive to decreasing the impact velocity and energy of abrasive particles, reducing the probability of microcrack generation, extension, and desquamation. It can be deduced that in the real-world environment, Scapharca subcrenata's left shell sustains more friction than its right shell. Thus, the coupled structure of the left shell is the result of extensive evolution.

Stiff, strong, zero thermal expansion lattices via material hierarchy

For engineering applications where tight dimensional tolerances are required, or for applications where materials are subjected to a wide range of temperatures it becomes desirable to reduce a material’s coefficient of thermal expansion. By carefully designing lattice microstructures, zero thermal expansion can be achieved. This work describes lattice microstructures that achieve zero expansion by utilizing either the Poisson effect to negate thermal expansion, or a curved, bi-material rib morphology. Previously described microstructures were composed of solid material constituents. The lattices presented here have structural hierarchy in which lattice ribs contain oriented porosity. This gives rise to improved strength and modulus, and provides additional design freedom associated with anisotropy.

Age-at-death estimation in Caucasian females from the morphological analysis of the sternal end of the fourth rib

The morphology evaluation of the sternal end of the fourth rib through the İşcan's "phases method" is considered one of the most reliable method for age-at-death estimation of corpses of unknown identity. This study aims to develop a component model for age estimation alternative to İşcan's method. A numerical score, ranging from 3 to 9, was assigned based on the morphology of surface (S), antero/posterior walls (W) and articular margins (M) of the sternal end of the fourth rib in 71 white female corpse. For each component a regression formula was determined. The best correlation between end rib morphology and age-at-death was obtained through the formula of multiple regression with two independent variables (articular surface and antero/posterior walls): Age (years)=6.37(S)+5.33(W)-17.15±3.3.

Vicariance and convergence in Magellanic and New Zealand long-looped brachiopod clades (Pan-Brachiopoda: Terebratelloidea)

Phylogenetic reconstructions using parsimony, maximum likelihood (ML), and Bayesian relaxed molecular clock analyses of ~2850 nucleotides of nuclear-encoded small and large subunit ribosomal DNAs (SSU and LSU rDNAs) from 14 long-looped (terebratelloid) ingroup and four short-looped (terebratulidine) outgroup brachiopod taxa, together with ML analyses of ~663 nucleotides of mitochondrial cytochrome oxidase subunit 1 (cox1) from 12 terebratelloid taxa, show that deep divergence separates taxa endemic to waters in the vicinity of New Zealand from those with a Magellanic distribution around South America and Antarctica. This deep divergence also separates Magellanic Terebratella dorsata from New Zealand Terebratella sanguinea, showing that they are not congeneric. Instead, they belong to separate ‘Magellanic’ (MAG) and ‘New Zealand’ (NZ) clades that first diverged about 82 Mya (95% highest posterior density, 48–120 Mya), correlating with separation between the NZ and Antarctic tectonic plates. Sequence analyses also reveal (1) that the Antarctic endemic taxa Magellania fragilis and Magellania joubini are not congeneric with Magellania venosa, suggesting that their previous placement in Aerothyris should be restored, and (2) that divergence between Antarctic and NZ species of the terebratulide Liothyrella occurred much later than plate separation, perhaps because of continuing gene flow caused by long-lived larvae. The topology of the rDNA and cox1 gene trees implies that radial ornament of the shell (‘ribbing’) has been gained (and/or lost) independently within the MAG and NZ clades. Radial ribs are widespread in articulate brachiopods throughout the Phanerozoic, but no comparisons of brachiopod rib morphology and morphogenesis have been published. Our comparisons of transverse shell mid-sections in the scanning electron microscope reveal no obvious evidence of differences in morphology between independently gained ribs. We also consider several ways in which ribs may affect fitness, including effects on hydrodynamics. Only scanty and inconclusive evidence is available, but we suggest that effects (if any) are likely to be of small magnitude; adaptive value of brachiopod shell ribs remains to be demonstrated.

A Fisk patent metallic burial case from Western Missouri: an interdisciplinary and comprehensive effort to reconstruct the history of an early settler of Lexington, Missouri

In 2006 a cast-iron coffin was discovered in an unmarked burial plot in Lexington, Missouri. A multifaceted investigation was conducted to provide historical documentation and possible identification of the individual. The coffin is an early Fisk Patent Metallic Burial Case. Osteological analyses indicate that the skeletal remains belong to a 20 to 30 year old white female who consistently ate an omnivorous diet with significant amounts of C4 plants or seafood. Rib morphology and her burial garments suggest she frequently wore restrictive clothing. No gross skeletal pathological lesions or trauma were observed except for a patch of reactive bone and an atypical pattern of bone remodeling on the visceral surface of the sixth rib. Subsequent bacterial DNA analysis of the ribs and sternum indicate the presence of tuberculosis infection. Although not conclusive, multiple lines of evidence are consistent with the skeletal remains representing Elizabeth (Triplett) Stewart who died in 1854 of pulmonary tuberculosis. This multidisciplinary research significantly contributes to the local history of Lexington, Missouri and provides a likely identification of the deceased individual for the Stewart Family.

Evolution of the Respiratory System in Nonavian Theropods: Evidence From Rib and Vertebral Morphology

Recent reports of region-specific vertebral pneumaticity in nonavian theropod dinosaurs have brought attention to the hypothesis that these animals possessed an avian-style respiratory system with flow-through ventilation. This study explores the thoracic rib and vertebral anatomy of Sinraptor, Allosaurus, Tyrannosaurus, and Deinonychus; four nonavian theropods that all show well-preserved thoracic vertebrae and ribs. Comparisons to the osteology and soft tissue anatomy of extant saurians provide new evidence supporting the hypothesis of flow-through ventilation in nonavian theropods. Analyses of diapophyseal and parapophyseal position and thoracic rib morphology suggest that most nonavian theropods possessed lungs that were deeply incised by the adjacent bicapitate thoracic ribs. This functionally constrains the lungs as rigid nonexpansive organs that were likely ventilated by accessory nonvascularized air sacs. The axial anatomy of this group also reveals that a crocodilian-like hepatic-piston lung would be functionally and biomechanically untenable. Taken together with the evidence that avian-like air sacs were present in basal theropods, these data lead us to conclude that an avian-style pulmonary system was likely a universal theropod trait.

New material of Menadon besairiei (Cynodontia: Traversodontidae) from the Triassic of Madagascar

ABSTRACT New specimens of the traversodontid cynodont Menadon besairiei from the Middle/Late Triassic ‘Isalo II’ beds of southwestern Madagascar are described. The new specimens include a skull and the first postcranial material described for this taxon. Although the referred skull differs from the holotype of M. besairiei in some regards, these differences are interpreted as intraspecific variation and preservational artifacts. The new material allows clarification of some aspects of the cranial morphology of Menadon, showing that, contrary to previous reports, this taxon had a well-developed internarial bar and four upper incisors. The postcranium of Menadon displays a mixture of advanced features observed in the South American traversodontid Exaeretodon, such as tall caudal neural spines, and primitive features observed in earlier traversodontids like Luangwa, such as heterogeneous rib morphology. A phylogenetic analysis incorporating information from the new specimens supports the placement of Menadon as the sister taxon to the clade Exaeretodon + Scalenodontoides.

Echolocation and the thoracic skeletons of bats: a comparative morphological study

ABSTRACT Using analyses of digital images of the thoracic skeletons of 16 species of bats (7 families) known to produce high intensity echolocation calls, we made qualitative and quantitative comparisons of the associations of thoracic skeletal features to echolocation behaviour and classification by family. The bats we examined showed significant differences in rib, sternal, manubrial and xiphoid morphology. Pteropodids (former Megachiroptera, non echolocating or, in the case of Rousettus aegyptiacus echolocating using orally-generated signals), were distinctly different from species of former Microchiroptera. Among former Microchiroptera, low duty cycle echolocators (Emballonuridae, most Mormoopidae, Vespertilionidae, and Molossidae) were generally more similar to one another than to high duty cycle echolocators (Hipposideridae and Rhinolophidae). Pteronotus parnellii, a high duty cycle echolocator, was more similar in thoracic morphology to other mormoopids than to other high duty cycle echolocators (h...

Buckman's Paradox: variability and constraints on ammonoid ornament and shell shape

Buckman's Law of Covariation states that ammonoid shell shape and ornamentation are typically correlated, such that compressed, involute forms have light ornament while more inflated, evolute forms have heavier ornament. Such covariation has been observed in many ammonoid groups, and implies a link between the morphogenesis of shell shape and ornamentation. However, other evidence suggests that while ornament growth is controlled by the genetic-developmental program of the ammonoid, shell shape is strongly influenced by environmental factors. These differing viewpoints lead to Buckman's Paradox – are ornamentation and shell shape tightly linked, as implied by Buckman's covariation, or is the morphogenesis of ornament controlled genetically, while shell shape is controlled environmentally? To address this issue, the variability of shell shape and rib morphology has been compared for a group of endemic acanthoceratid ammonites from the Cretaceous Western Interior Seaway of North America. If Buckman's Law holds due to a morphogenetic connection between shell shape and ornamentation, we would expect taxa with more variable shell shapes to also show more variable rib features and growth. Morphometric analysis of seven shell shape and two rib characters for the Western Interior acanthoceratids finds no such correlation, suggesting that shell shape and rib growth are controlled by different processes. Indeed, rib growth appears to be more constrained than shell shape, consistent with the view that ornamentation is more tightly controlled by the developmental-genetic growth program of the ammonoid. These results emphasize the complexity of ammonoid morphogenesis and highlight our limited understanding of the causes underlying Buckman's Law.

Formation of Barrier Ribs for Plasma Display Panel via Capillary Molding–Effects of Sintering Conditions on Barrier Rib Morphology

Various types of barrier ribs for a plasma display panel were formed via a capillary molding process. A thermosetting paste was filled into cavities of working molds by means of capillary action and was cured prior to removal of the molds. The working molds were prepared by curing liquid polydimethylsiloxane on master molds that were produced from a photoresist. It was demonstrated that various types of barrier ribs could be produced successfully by sintering the ribs formed by the molding process. In addition, the effects of solid loading in the paste, prefiring temperature and type of barrier ribs on the morphologies of the ribs were investigated.

Costoplasty in adolescent idiopathic scoliosis. Objective results in 55 patients

Costoplasty can reduce the important cosmetic deformity of rib prominence in scoliosis but there are few objective reports of correction. We recorded the results of three objective methods of assessing back shape before and after short-segment costoplasty in 55 patients. We showed that significant improvement was maintained over a two-year follow-up period. Primary costoplasty at the time of scoliosis surgery (n = 35) achieved greater proportional correction than secondary costoplasty performed after fusion of the spine (n = 20). The rib segments removed at primary surgery provided enough bone for the autogenous graft; harvesting from the pelvis was unnecessary. We report a new classification of rib morphology which helps in planning the site and extent of costoplasty, and in predicting the possible correction.

Independent test of the fourth rib aging technique.

The sternal surface of the 4th rib has been suggested as a useful predictor of adult age-at-death (Iscan et al.: Journal of Forensic Sciences 29:1094-1104, 1984; American Journal of Physical Anthropology 65:147-156, 1984). We tested its ability to do so in two tests. In the first, we developed a method of seriation and target age assignment for the 4th rib so that inaccuracy and bias of the method could be assessed by decade. We found that the 4th rib shows characteristic changes in morphology with age and can be included in multifactorial age estimates. In the second test, we applied the phase method developed by Iscan et al. (Journal of Forensic Sciences 29:1094-1104, 1984). The results of our three judges were generally similar to those reported by Iscan and Loth (Journal of Forensic Sciences 31:122-132, 1986). Measures of race differences in 4th rib morphology were included in both tests. Americans of African descent (black) showed a non-significant trend for the rib changes to be delayed compared to Americans of European descent (white). This is in contrast to the work of Iscan et al., which predicted that blacks would show a tendency toward accelerated rib changes compared to whites, especially after the early 30s (phases 5-7) (Iscan et al.: Journal of Forensic Sciences 32(2):452-466, 1987).

Age Estimation from the Rib by Phase Analysis: White Males

The determination of age at death is an important part of physical and forensic anthropology. Techniques now in use vary from direct observation of a bone to microscopic examination of a given segment. This study introduces the sternal end of the rib as a new site for age estimation by direct observation. The sample consisted of 118 white male ribs of verified age, sex, and race. The ribs were assigned to one of nine phases (0 through 8) based on changes noted at the costochondral junction. These included the formation of a pit, its depth and shape, configuration of the walls and rim surrounding it, and the overall texture and quality of the bone. Statistical analysis indicated that these changes were age related. It was further revealed that metamorphosis was most rapid and uniform from the mean age of 17 to 28 years (Phases 1 through 4). The rib morphology was more varied after age 39 (Phase 5) resulting in a wider range for the predicted age. Our study concluded that the sternal rib end may yield a similar degree of accuracy to the pubic symphysis and perhaps better than that for cranial sutural closure. Our technique also enables the forensic scientist to use the rib for corroboration with age estimations obtained by traditional methods.

Osteología comparada de las familias Nothosauridae y Simosauridae (Reptilia. Sauropterygia)

The alleged homodont condition of Simosaurus is not exact, symphisiary and postsymphisiary pieces can be differenciated, based on morphological and size criteria. The dental morphology of Simosaurus is unique within the Sauropterygia, with teeth whose basal diameter has a great relative developpment. The morphology of vertebral centrum between Nothosauridae and Simosauridae is compared. The first ones have a morphotype called Kreuzform (dorsal region of centrum) facing that of Simosauridae, here called Fosetado (pitted), A typical characteristic of Simosaurus is the occurrence (in the neural arch) of additional articulatin,g structures (infrazygapophyses, Huene, 1952). From the consideration of morphometric variationof centrum in N. raabi SCHROEDER, 1914, it can be concluded that the cervical vertebrae of Nothosaurus are relatively longer and deeper than the thoracic ones, The topographic variation of diameter and Ienght of centrum in Simosaurus is more accused than in Nothosaurus , while depth is more constant. Based on morphometric criteria the vertebral centra no pachyostotic of Pachypleurosaurs (generally smaller in size) can not be discriminated from those of Nothosauridae. The rib morphology of Simosaurus is similar to that of other Notbosaurs. The coracoid of Simosaurus is stronger and unlike Nothosaurus the glenoid notch has a typically anterior position. Simosaurus has a more slender humerus than the rest of Nothosaurs. The analysis of the different genera proposed as Simosauridae up to date, leads towards the conclusion that it is a monogeneric family. Dentary and postcraneal diagnosis of this taxon is proposed.