Anatomy of a serial killer: differential diagnosis of tuberculosis based on rib lesions of adult individuals from the Coimbra Identified Skeletal Collection, Portugal

The role of new bone formation on visceral surfaces of ribs in the diagnosis of tuberculosis (TB) in past human populations has been explored by many researchers, using both skeletal remains with known causes of death and archaeological samples. This study focuses, firstly, on adult skeletons from the Coimbra Identified Skeletal Collection in Portugal and investigates the skeletal manifestations of individuals known to have died from TB; secondly, this study focuses on the role of rib lesions in the diagnostic criteria for TB. One hundred and fifty-seven males and 106 females aged between 22-87 years were examined; causes of death were assigned as pulmonary TB, extrapulmonary TB, and pulmonary non-TB; a control group, extrapulmonary non-TB, was selected from the remaining individuals. Of individuals with rib lesions, 85.7% (69/81) had pulmonary or extrapulmonary TB as an assigned cause of death, while 17.8% (16/90) of individuals with rib lesions had a non-TB cause of death. Rib lesions were significantly more common in individuals who had died from TB, although the lesions cannot be considered pathognomonic for TB. In individuals dying from pulmonary TB, ribs in the central part of the rib cage were most affected, at their vertebral ends. The lower part of the rib cage may be a marker for peritoneal TB, and "coral-like" new bone formation on ribs may be an indicator of neoplastic disease. Further work on rib involvement in TB in clinical contexts, and the study of further documented skeletal collections, are recommended.     

Vertebral and rib anatomy in Caperea marginata: Implications for evolutionary patterning of the mammalian vertebral column

The pygmy right whale, Caperea marginata, is a rare mysticete cetacean with an unusual suite of axial skeletal characters. Distally expanded first ribs, a long thorax with broadly overlapping vertebral transverse processes, plate‐like posterior ribs, and a short tail contrast with other cetaceans and suggest unique developmental patterning. Twenty‐four individuals of diverse ontogenetic age were available for analysis. Multiple, variable examples of incomplete rib fusion in dependent calves indicate that the first rib of adults is an ontogenetic fusion product of ribs 1 and 2. The composite rib articulates by way of its anterior (Rib1) component to the sternum and by way of its posterior (Rib2) component with thoracic vertebra 2. Thoracic vertebra 1 lacks rib articulations. When rib fusion is taken into account, the most frequent column formulas are C7T18L1Cd16–17 = 42–43 and C7T17L1Cd16–18 = 41–43. Thoracic and lumbar series are not reciprocal in count, arguing against their developmental linkage. Instead, parallel reduction in both lumbar and caudal counts supports the existence of neocete patterning in Caperea, as in all other living cetaceans. Ontogenetic vertebral column elongation is most marked in the posterior thorax, lumbos, and anterior tail. Vertebrae in these column regions are excellent predictors of total body length.     

Brief communication: histological age estimation using rib and clavicle.

Histological methods for estimating age at death using osteon population densities for the rib, clavicle, and rib and clavicle combined are presented. Predicting formulas were generated from a sample of 40 individuals of known age, sex, and race. Independent samples of 12 ribs and 7 clavicles were used to test the formulas. Mean differences between known and predicted ages were 1.1 years, 2.6 years, and 3.4 years for the clavicle, rib and clavicle combined, and rib formulas respectively. An analysis of variance found no significant differences among the means for predicted and known ages. Since the formula based upon rib and clavicle combined has the higher standard error and r2, and includes data from different bones, it should provide better overall accuracy and reliability, and is recommended whenever both bones are available.     

A model for studies of the deformable rib cage.

An earlier model for the study of rib cage mechanics was modified so that rib deformity in scoliosis could be better represented. The rigid ribs of that model were replaced by five-segment deformable ribs. Literature data on cadaver rib mechanical behavior were used to assign stiffnesses to the new individual model ribs so that experimental and model rib deflections agreed. Shear and tension/compression stiffnesses had little effect on individual rib deformation, but bending stiffnesses had a major effect. Level-to-level differences in mechanical behavior could be explained almost exclusively by level to level differences in the rib shape. The model ribs were then assembled into a whole rib cage. Computer simulations of whole rib cage behaviors, both in vivo and in vitro, showed a reasonable agreement with the measured behaviors. The model was used to study rib cage mechanics in two scolioses, one with a 43 degrees and the other with a 70 degrees Cobb angle. Scoliotic rib cage deformities were quantified by parameters measuring the rib cage lateral offset, rib cage axial rotation, rib cage volume and rib distortion. Rib distortion was quantified both in best-fit and simulated computer tomography (CT) scan planes. Model rib distortion was much smaller in best-fit planes than in CT planes. The total rib cage volume changed little in the presence of the scolioses, but it became asymmetrically distributed.     

An analysis of possible movements of human upper rib cage

A geometrically realistic mathematical model of the first six ribs and vertebrae of the human rib cage is described. Under the assumption that the individual elements of the rib cage do not deform significantly, the possible range of movements of the model are determined subject to the constraint that the joint surfaces remain in contact. It is shown that normal movements of the ribs cannot be described as a rotation about a single fixed axis. The possible movements of the ribs are analyzed in terms of the misfit incurred at the costovertebral joint surfaces. This analysis shows that there is a movement, corresponding to lateral expansion of the rib for an increase in anteroposterior diameter, in which the misfit at the joint is minimized and also that small deviations from this movement involve only very small degrees of misfit at the joint surfaces. It is concluded that many observed "deformations" of the chest wall can be explained by rigid ribs and normal movements at the costovertebral joints. The interaction between the ribs and the spine is analyzed. It is shown that there can be considerable independent movement of the sternum and the spine, thus allowing mobility of the spine without forcing concomitant movements of rib cage.     

Direct observation of protein secondary structure in gas vesicles by atomic force microscopy.

The protein that forms the gas vesicle in the cyanobacterium Anabaena flos-aquae has been imaged by atomic force microscopy (AFM) under liquid at room temperature. The protein constitutes "ribs" which, stacked together, form the hollow cylindrical tube and conical end caps of the gas vesicle. By operating the microscope in deflection mode, it has been possible to achieve sub-nanometer resolution of the rib structure. The lateral spacing of the ribs was found to be 4.6 +/- 0.1 nm. At higher resolution the ribs are observed to consist of pairs of lines at an angle of approximately 55 degrees to the rib axis, with a repeat distance between each line of 0.57 +/- 0.05 nm along the rib axis. These observed dimensions and periodicities are consistent with those determined from previous x-ray diffraction studies, indicating that the protein is arranged in beta-chains crossing the rib at an angle of 55 degrees to the rib axis. The AFM results confirm the x-ray data and represent the first direct images of a beta-sheet protein secondary structure using this technique. The orientation of the GvpA protein component of the structure and the extent of this protein across the ribs have been established for the first time.     

Intercostal variation for age estimation--are the standards for the right 4th rib applicable for other ribs?

Age estimation of unknown skeletal remains is very important in forensic medicine. Morphologic methods are fast and easy to use for purpose of age determination. The sternal ends of the ribs are a reliable method of age estimation from late adolescence to old age. Iscan et al developed a phase analysis method for the right 4th rib that was sex and race specific. The purpose of this study is to determine the accuracy of the standards of age estimation from the right 4th and other rib using the phase analysis for the Turkish population. The sample consisted of right and left 3rd, 4th and 5th ribs from 34 Turkish women and 76 men. There were statistically significant variations found on the right 5th, left 3rd, 4th, and 5th ribs according to these standards in men for phases 5, 6, and 7. For women, all the right and left ribs included in this study were in concordance with right 4th rib standards in all phases.     

Using stable isotope analysis to examine the effect of economic change on breastfeeding practices in Spitalfields, London, UK

Breastfeeding patterns were subject to a number of fads in 18th and 19th century Britain. Feeding infants by hand, rather than maternal breastfeeding or wet-nursing, became more prevalent among both the wealthy and poor. Substitute foods may have been a convenient alternative for mothers employed away from the household. This study used stable isotope ratio analysis to examine the weaning schedule in the 18th and 19th century skeletal assemblage from Spitalfields, London, UK. Analysis of 72 juvenile ribs revealed δ(15) N elevations of 2-3‰ above the adult mean for individuals up to the age of two, while elevations of 1-2‰ were observed in δ(13) C for the first year of life. This suggests that the introduction of solid foods took place before the end of the first year, and that breastfeeding had entirely ceased by 2 years of age. The age at death of many of these infants is known from historical records, and can be used to pinpoint the amount of time required for the breast milk signal to be observed in the stable isotope ratios of rib collagen. Results show that a δ(15) N elevation can be detected in the ribs of individuals who died as young as 5-6 weeks. Not all individuals at Spitalfields were breastfed, and there may not have been a single uniformly practiced weaning scheme. There is, however, more evidence for prolonged breastfeeding during the 19th century than the 18th century.     

The myth of dorsal ribs in gnathostome vertebrates

Traditionally, two types of rib are distinguished in gnathostomes: dorsal (upper) and ventral (lower, pleural) ribs. They are defined according to their position in the connective tissue system of the body: dorsal ribs develop at the intersection of the serially arranged myosepta with the horizontal septum that separates epaxial from hypaxial musculature, whereas ventral ribs develop at the intersection of myosepta with the peritoneum and usually encircle the body cavity. Distribution of rib types among gnathostomes has traditionally been reported as follows: elasmobranchs have dorsal ribs; all Actinopterygii have only ventral ribs with the exception of polypterids, and two subgroups of teleosts, which supposedly also have dorsal ribs; within Sarcopterygii tetrapods have dorsal ribs, whereas dipnoans have ventral ribs. Here, we report the development of ribs in polypterids, a taxon playing a crucial role in discussions on rib homology. We demonstrate that putative dorsal ribs of polypterids have a unique ontogeny and represent an autapomorphy of this taxon. We discuss previous hypotheses of rib homology and offer a more plausible (i.e. more parsimonious) alternative to the conventional interpretation. We conclude that dorsal ribs do not exist and that ribs of gnathostomes are ventral ribs.     

The axial skeleton of the labyrinthodont Eogyrinus attheyi

An articulated length of vertebral column is used as a basis for the reconstruction of the salient features of the axial skeleton of the embolomerous anthracosaur Eogyrinus attheyi Watson, together with other material, including the holotype, in the Hancock Museum, Newcastle upon Tyne.
The trunk vertebrae are typically emboloinerous, with disoshaped notochordal pleuro-centra, firmly attached by broad facets to this neural arches, and much thinner intercentra. Regional variation is chiefly concerned with the span of the transverse processes, which diminishes posteriorly, and the associated separation of the two heads of each rib. A longitudinal series of trunk ribs, of diminishing length from the mid-trunk backwards, is reconstructed.
Eogyrinus has a normal tetrapod sacrum with one characteristic sacral rib. The first few caudal vertebrae bear ribs of unusual form, (of which four are preserved in sequence in the articulated specimen. The fifth caudal intercentrum bears the first and largest haemal arch and the pleurocentrum of the seventh caudal is distinguished by marked muscle origins presumably for the caudifemoral muscles.
The probability that Eogyrinus, like the few other embolomeres known, had an unusually long vertebral column for a labyrinthodont, is supported by an orthometric comparison using Romer's data on the American form Archeria.     

Geometry and respiratory displacement of human ribs

The three-dimensional coordinates of points in the ribs of two supine relaxed males, holding their breath at functional residual capacity (FRC) and with their glottis closed at total lung capacity (TLC), were obtained from volumetric X-ray computed tomographical images. The orientation of planes that best fit the data for each rib at each lung volume and the circular arcs that fit the points in the planes of the ribs were determined, and average values of these geometrical parameters for ribs 3-7 are reported. The planes of the ribs at TLC can be described as displaced from the planes at FRC by a rotation about an axis that passes near the spine. The pump handle and bucket handle components of rotation are 11 and 13 degrees, respectively, for rib 3 and both decrease with increasing rib number to 7 and 10 degrees at rib 7. The angles between the axes of rotation and the midplane are approximately 35 degrees for all 5 ribs. The radii of the circular arcs fit to the data at TLC are slightly larger than those at FRC, and this suggests that there is a small component of rotation normal to the plane of the rib.     

Secondary osteon and Haversian canal dimensions as behavioral indicators

Variation in the size of structures within mature cortical bone is relevant to our understanding of apparent differences between human samples, and it is relevant to the development of histologically based age-estimation methods. It was proposed that variation may reflect effects of physical activity, through biomechanical and/or metabolic mechanisms. If these factors are local, femoral osteon area (On.Ar) should be more histologically variable than On.Ar in ribs. Ribs should show a higher variation in Haversian canal area (H.Ar) if they are sites of more remodeling activity and hence of arrested refilling of secondary osteons at time of death. This study compares On.Ar and H.Ar of secondary osteons from femora (15) and ribs (29) from 44 Holocene (Later Stone Age) foragers from South Africa (M = 19, F = 25) to values from paired femora and ribs from historic samples (Spitalfields and St. Thomas, 20 pairs from each). Fixed-effects analysis of variance demonstrates rib On.Ar to be significantly smaller than femur, but with no sex or age effects. The femur-to-rib On.Ar ratio is lower for the Holocene foragers than for the two modern samples because of relatively large rib On.Ar. Femora and ribs from the same skeleton normally show femoral On.Ar larger than rib On.Ar (37/44 pairs). Mean femoral values of On.Ar are more diverse than rib On.Ar values, but within-sample coefficients of variation are similar. Values for H.Ar are highly variable and do not reflect anatomical site, age, sex, or population effects. The patterning of osteon size does not appear to be linked to physical activity or to different rates of metabolic activity within the skeleton, at least not in a straightforward way.     

Geometry and kinematics of dog ribs

Five anesthetized supine beagle dogs were scanned using a fast, multislice computed tomographic X-ray technique to determine the orientation of the ribs at total lung capacity (TLC) and functional residual capacity (FRC). A plane was fit to each rib using a coordinate system in which the z-axis was aligned approximately cephalocaudally and the x-z-plane coincided with the sagittal midplane. The orientation of each plane was described by "pump-handle" and "bucket-handle" angles. The ribs rotated downward and inward during a passive deflation of the lungs from TLC to FRC. Rib displacement was not uniform: bucket-handle motion was predominant in the upper ribs, and pump- and bucket-handle motions were equal in the lower ribs. The change in the pump-handle angles between TLC and FRC was approximately 6 degrees for ribs 3-8, and the change in the bucket-handle angles decreased with rib number from 16 degrees for rib 3 to 6 degrees for rib 8. Rib shape was described by fitting an ellipse to the data for each rib; the ribs became larger and more circular with increasing rib number.     

Analysis of quantitative methods for rib seriation using the Spitalfields documented skeletal collection

Accurate rib seriation is essential in forensic anthropology and bioarchaeology for determination of minimum numbers of individuals, sequencing trauma patterns to the chest, and identification of central ribs for use in age estimation. We investigate quantitative methods for rib seriation based on three metric variables: superior (anterior) costo-transverse crest height (SCTCH), articular facet of the tubercle-to-angle length (AFTAL), and head-to-articular facet length (HAFL). The sample consists of complete but unseriated sets of ribs from 133 individuals from the documented (known age and sex) and undocumented skeletal collections of Christ Church Spitalfields, London. This research confirms the results of an earlier study (Hoppa and Saunders [1998] J. Forensic. Sci. 43:174-177) and extends it with the application of two new metric traits and further analyses of sex differences. Analyses of variance showed that SCTCH and AFTAL are significantly associated (P < 0.001) with rib number. Tukey tests of pairwise rib comparisons revealed that for two dimensions (SCTCH and AFTAL), the central ribs (3rd-6th) are significantly distinct from each other (P < 0.05). Using simple ranking of either the SCTCH or AFTAL traits, the proportion of correctly identified ribs within +/-1 position was 80%, compared to initial seriation using morphological methods (Dudar [1993] J. Forensic. Sci. 28:788-797; Mann [1993] J. Forensic. Sci. 28:151-155). Significant sex dimorphism was also identified for these two traits. Analysis of the HAFL trait produced somewhat equivocal results, suggesting that this variable is not reliable for rib seriation. The variable SCTCH proves to be the most useful dimension for seriation, and shows that all but the 7th-9th ribs can be distinguished from others in the sequence, with important results for the 4th rib, where ranking allowed identification in 86% of cases, consistent with morphological methods for intact ribs.     

An analysis of action of intercostal muscles in human upper rib cage

The actions of the intercostal and paraspinal muscles in stabilizing the human upper rib cage have been analyzed using a geometrically realistic mathematical model of the first six ribs, vertebrae, and associated musculature. The model suggests roles of the deep layers of erector spinae in stabilizing the vertebral column so that it can support the loads placed upon it by the ribs under physiological load. If we assume that the tension exerted by an intercostal muscle is proportional to its local thickness, the model predicts that the observed distribution of intercostal thickness is close to that which minimizes the stresses in ribs when the model is subjected to peak physiological load. The observed shape of the ribs are optimal to withstand the calculated pattern of loading along their length. These calculations raise the hypothesis that the arrangement of intercostal musculature and rib geometry result in an optimally light rib cage, which is capable of withstanding the loads placed upon it. The analysis of the mechanics of the entire model indicates that the geometrical simplifications made in Hamberger's model are not valid when applied to the rib cage.     

Respiratory effect of the lower rib displacement produced by the diaphragm

The diaphragm acting alone causes a cranial displacement of the lower ribs and a caudal displacement of the upper ribs. The respiratory effect of the lower rib displacement, however, is uncertain. In the present study, two sets of experiments were performed in dogs to assess this effect. In the first, all the inspiratory intercostal muscles were severed, so that the diaphragm was the only muscle active during inspiration, and the normal inspiratory cranial displacement of the lower ribs was suppressed at regular intervals. In the second experiment, the animals were given a muscle relaxant to abolish respiratory muscle activity, and external, cranially oriented forces were applied to the lower rib pairs to simulate the action of the diaphragm on these ribs. The data showed that 1) holding the lower ribs stationary during spontaneous, isolated diaphragm contraction had no effect on the change in lung volume during unimpeded inspiration and no effect on the fall in pleural pressure (Ppl) during occluded breaths; 2) the procedure, however, caused an increase in the caudal displacement of the upper ribs; and 3) pulling the lower rib pairs cranially induced a cranial displacement of the upper ribs and a small fall in Ppl. These observations indicate that the force applied on the lower ribs by the diaphragm during spontaneous contraction, acting through the interdependence of the ribs, is transmitted to the upper ribs and has an inspiratory effect on the lung. However, this effect is very small compared to that of the descent of the dome.     

Role of rib cage elastance in the coupling between the abdominal muscles and the lung.

The abdominal muscles expand the rib cage when they contract alone. This expansion opposes the deflation of the lung and may be viewed as pressure dissipation. The hypothesis was raised, therefore, that alterations in rib cage elastance should affect the lung deflating action of these muscles. To test this hypothesis and evaluate the quantitative importance of this effect, we measured the changes in airway opening pressure (Pao), abdominal pressure (Pab), and rib cage transverse diameter during isolated stimulation of the transversus abdominis muscle in anesthetized dogs, first with the rib cage intact and then after rib cage elastance was increased by clamping the ribs and the sternum. Stimulation produced increases in Pao, Pab, and rib cage diameter in both conditions. With the ribs and sternum clamped, however, the change in Pab was unchanged but the change in Pao was increased by 77% (P < 0.001). In a second experiment, the transversus abdominis was stimulated before and after rib cage elastance was reduced by removing the bony ribs 3-8. Although the change in Pab after removal of the the ribs was still unchanged, the change in Pao was reduced by 62% (P < 0.001). These observations, supported by a model analysis, indicate that rib cage elastance is a major determinant of the mechanical coupling between the abdominal muscles and the lung. In fact, in the dog, the effects of rib cage elastance and Pab on the lung-deflating action of the abdominal muscles are of the same order of magnitude.     

Rib remodeling dynamics in a skeletal population from Kulubnarti, Nubia

Bone remodeling variables in the rib were analyzed for a skeletal population of medieval antiquity (ca. A.D. 550-1450) from Kulubnarti, in Sudanese Nubia. The skeletal remains are naturally mummified and in an excellent state of preservation. The study sample consists of thin sections from the ribs of 80 individuals, ranging in age from 15-50+ years. Ribs were examined using a standard microscope and image analysis software. Numbers of intact osteons, fragmentary osteons, forming osteons, and resorption spaces were counted, osteon and Haversian canal areas were measured, and several variables were calculated to assess morphometric and remodeling status in the rib. Variables calculated included mean annual activation frequency, mean bone formation rate, and net osteonal remodeling. Results indicate that age changes are consistent with those observed for other archaeological and modern samples. High numbers of resorption spaces in young males may reflect slower skeletal development in boys compared to girls. Comparisons of rib data with results of a previous study on patterns of femoral bone remodeling in the same population indicate that ribs have more osteons and higher bone formation rates compared to the femur. Also, sexual differences in osteon size observed in the femur were not observed in the rib. Activation frequency and bone formation rate are low in the Kulubnarti population compared to previously published data for a modern sample, a finding consistent with reported results from other archaeological samples. Genetic factors influencing the minimum effective strain setpoint and duration of skeletal maturation, in addition to repetitive high strains at Kulubnarti, may contribute to observed differences.