In-vivo analysis of sternal angle,sternal and sternocostal kinematics in supine humans during breathing

This paper aims at contributing to the understanding of the combination of in vivo sternum displacement, sternal angle variations and sternocostal joints (SCJ) kinematics of the seven first rib pairs over the inspiratory capacity (IC). Retrospective codified spiral-CT data obtained at total lung capacity (TLC), middle of inspiratory capacity (MIC) and at functional residual capacity (FRC) were used to compute kinematic parameters of the bones and joints of interest in a sample of 12 asymptomatic subjects. 3D models of rib, thoracic vertebra, manubrium and sternum were processed to determine anatomical landmarks (ALs) on each bone. These ALs were used to create local coordinate system and compute spatial transformation of ribs and manubrium relative to sternum, and sternum relative to thoracic vertebra. The rib angular displacements and associated orientation of rotation axes and joint pivot points (JPP), the sternal angle variations and the associated displacement of the sternum relative to vertebra were computed between each breathing pose at the three lung volumes. Results can be summarized as following: (1) sternum cephalic displacement ranged between 17.8 and 19.2 mm over the IC; (2) the sternal angle showed a mean variation of 4.4° ± 2.7° over the IC; (3) ranges of rib rotation relative to sternum decreased gradually with increasing rib level; (4) axes of rotation were similarly oriented at each SCJ; (5) JPP spatial displacements showed less variations at first SCJ compared to levels underneath; (6) linear relation was demonstrated between SCJ ROMs and sternum cephalic displacement over the IC.     

Real mineral density of the sternum

Mineral density of the sternum is insufficiently known. The aim of this research was to investigate mineralisation of the sternum and collect normative data on mineral density of the standard male and female sternum in elderly people (average age of female samples was 64 and male's was 62 years). The research was conducted on 93 cadaveric sternums, 56 male and 37 female samples. To determine regional mineral density of the sternum each sample was cut into six bony segments (Figure 1). Mineral density of every segment was determined using the method of ashing. Male sternums were on average denser than female ones in all segments. Average mineral density of the manubrium in women was 0.169 g/cm3 and 0.220 g/cm3 in men. Average mineral density of the body of the sternum also showed existence of sex difference; it was 0.160 g/cm3 in women and 0.227 g/cm3 in men. Both male and female sternums showed identical mineral density distribution. Mineral density of the manubrium and the body was roughly equal, while the analysis of longitudinal segments showed that the central part of both the manubrium and the body of the sternum was denser than lateral parts. Complex determination of the real mineral density for defined segments of the sternum and analysis of the obtained results were used to create the map of mineral density of the sternum in men and women (Figure 2). Maximum density values were four times greater than minimum density values for analysed samples. These data showed that osteoporosis also occurs on the sternum. Loss of structure and lower mineral density decrease the sternum quality and increase the risk of sternal dehiscence after median sternotomy.     

Anatomical considerations in sternal puncture

The thickness of the manubrium, the width and thickness of the body of the sternum at the level of second intercostal space as well as the thickness of the spongiosa and outer and inner compact layers have been measured in 67 human cadavers. Consequently, it is recommended that sternal puncture be made at the level of the second intercostal space in the adult and at the manubrium in children. Depth of puncture should not exceed 4 mm. Sternal puncture can thereby be done with greater confidence of avoiding penetration of the sternum, a potentially serious complication.     

Genetic and Environmental Influences on the Tracking of Body Size from Birth to Early Adulthood

Objective: This study identified genetic and environmental influences on the tracking of body size from birth to 16 to 18.5 years of age. Research Methods and Procedures: Longitudinal information was collected from a nationally representative sample of Finnish twin adolescents (birth cohorts 1975 to 1979) and their parents through questionnaires mailed when the twins were ages 16 and 18.5 years old. The sample included 702 monozygotic, 724 same‐sex dizygotic, and 762 opposite‐sex dizygotic sets of twins. The measures used were length, weight, ponderal index (kilograms per cubic meters), and gestational age at birth, and height, weight, and body mass index (kilograms per square meters) at 16 to 18.5 years of age. The changes in genetic and environmental influences on body size from birth to early adulthood were analyzed by quantitative genetic modeling. Results: The twins who had a higher weight or ponderal index at birth were taller and heavier in early adulthood, whereas those who were longer at birth were taller, but not heavier, later in life. Adult height was affected more by the birth size than body mass index. In the genetic modeling analyses, the genetic factors accounting for the variation of body size became more apparent with age, and both genetic and environmental influences on stature had a sizable carry‐over effect from birth to late adolescence, whereas for relative weight, the influences were more age‐specific. Discussion: The genetic and environmental architecture of body size changes from birth to adulthood. Even in monozygotic twins who share their genetic background, the initially larger twin tended to remain larger, demonstrating the long‐lasting effects of fetal environment on final body size.     

由胸骨长度估算中国北方成年人身高的回归方程

调查了中国北方28具(男15、女13)汉族成年人尸体身高、胸骨全长、胸骨柄长和胸骨体长的均值,并计算了胸骨的长度与身高的相关系数。除男性胸骨全长高度相关外,其余皆为中度相关。由胸骨全长推算身高的回归方程式,较由胸骨柄长和胸骨体长推算身高的回归方程式,有较高的相关系数和较低的标准估计误差。由胸骨体长推算也较由胸骨柄长推算为佳。     

Cell hypertrophy and type X collagen synthesis in cultured articular chondrocytes

Articular cartilage is a permanent tissue whose cells do not normally take part in the endochondral ossification process. To determine whether articular chondrocytes possess the potential to express traits associated with this process such as cell hypertrophy and type X collagen, chondrocytes were isolated from adult chicken tibial articular cartilage and maintained in long-term suspension cultures. As a positive control in these experiments, we used parallel cultures of chondrocytes from the caudal portion of chick embryo sternum. Both articular and sternal chondrocytes readily proliferated and progressively increased in size with time in culture. Many had undergone hypertrophy by 4-5 weeks. Analysis of medium-released collagenous proteins revealed that both articular and sternal chondrocytes initiated type X collagen synthesis between 3 and 4 weeks of culture; synthesis of this macromolecule increased with further growth. Immunofluorescence analysis of 5-week-old cultures showed that about 15% of articular chondrocytes and 30% of sternal chondrocytes produced type X collagen; strikingly, there appeared to be no obvious relationship between type X collagen production and cell size. The results of this study show that articular chondrocytes from adult chicken tibia possess the ability to express traits associated with endochondral ossification when exposed to a permissive environment. They suggest also that the process of cell hypertrophy and initiation of type X collagen synthesis are independently regulated both in articular and sternal chondrocytes.     

Geometric morphometrics of the mandible in the Iberian desman,Galemys pyrenaicus (Mammalia: Soricomorpha): Is there a significant variation in form during post-weaning life?

Geometric morphometrics was applied on the mandible of the Iberian desman, Galemys pyrenaicus, to determine for the first time possible sexual and post-weaning shape variation of this structure in a talpid species. Analyses were complemented by evaluating the effect of sex and age on size. The sample consisted of collection specimens from locations in the Cantabrian Mountains (northern Spain). Desmans were grouped into four relative age classes according to tooth wear. The shape of the internal side of the mandible was represented by 15 two-dimensional landmarks. Once young desmans leave the nest there is no significant variation in the form (size and shape) of the mandible. Thus, possible osseous changes and tooth abrasion derived from ageing do not produce obvious variation in mandible form. Mandible shape was significantly correlated with mandible size, resulting in a range of shapes that varies from a slender to a robust morphology. This variation was independent of geographic factors. Since the effect of non-heritable environmental influences on mandible size and shape was negligible, it can be considered that the mandible form of post-weaned desmans is the direct product of interactions between different developmental processes.     

Morphometric analysis of the sternum

Sternum has a great clinical significance, considering that median sternotomy is the most common surgical approach used in cardiac surgery. The aim of this study is to standardize the sternum according to size, shape and sex and to obtain ranges of the "standard sternum". The study was done on 55 male and 35 female sterna of the average age of 65. Complex morphometric analysis of breadth, length and thickness of the sterna were performed on sternal segments which were defined by costal notches. Morphometric analysis shows that the general sternum structure in the females and in the males is equal. The standard dimensions of female and male sternum were determined. Standardization according to shape suggests that there is one standard sternum shape present in more than 2/3 of analysed samples of both sexes.     

Post‐weaning ontogeny of the mandible in fossorial water voles: ecological and evolutionary implications

Ventura, J. and Casado‐Cruz, M. 2011. Post‐weaning ontogeny of the mandible in fossorial water voles: ecological and evolutionary implications. —Acta Zoologica (Stockholm) 92 : 12–20. Geometric morphometrics was applied to the mandible of fossorial water voles (Arvicola terrestris monticola) to determine size and shape variations in this structure during post‐weaning ontogeny. The sample consisted of collection specimens obtained in the Aran Valley (Spain), which were grouped into six age classes. Mandible size and shape did not differ significantly between sexes, but between age classes. Mandible size accounted significantly for the shape variation. After the size‐related differences were removed, the mandible shape did not show significant sexual dimorphism but differences by age remained significant. The main shape changes occur between the third and tenth weeks of life and are related to the shift from suckling to a herbivorous diet. Although mandible shape was less remodelled after that age, an appreciable variation also occurs during adulthood. Age‐related changes lead to enhancing the digging potential of the mandible, which in adults becomes a robust structure with an increased surface and stronger crests for muscle insertion. As part of the mandible shape variation was not related to the size‐dependent adjustment and diet does not vary significantly between juvenile and adult voles, shape changes that occur during adulthood can be related to the mechanical stress derived from digging activities.     

Internal fixation of the sternum in median sternotomy dehiscence.

Sternal dehiscence may be defined as separation of the bony sternum and manubrium following median sternotomy. It may occur at any time postoperatively and has various etiologies. Restoration of sternal integrity in sternal dehiscence is a challenging problem, particularly when associated with deep-seated infection. This report reviews a single-stage technique that virtually eliminates the infected sternotomy wound and provides anatomic reduction and stabilization of the sternum. Complete debridement of infected and/or nonviable soft tissue, bone, and cartilage is followed by pulse irrigation. Parallel stainless steel mandibular reconstruction plates are then placed on each side of the remaining sternum and wired together. One or more transmanubrial compression plates may be added. Bilateral pectoralis major musculocutaneous flap advancement and primary skin closure is performed over two to three closed suction drains. From January of 1994 to July of 1996, this technique was used by the same surgeon in 26 male and 4 female patients aged 43 to 78 years (mean = 61). Indications for the operation were sternal dehiscence with infection (osteomyelitis and/or mediastinitis) in 14 patients and sternal dehiscence without infection in 16 patients. All patients survived to discharge with mean time on the ventilator, intensive care unit length of stay, and postoperative length of stay of 0.7, 2, and 8 days, respectively. Choice and duration of antibiotics were based on culture results and operative findings. Subsequent hardware removal was necessary in one patient for hardware loosening and three patients for late periplate infection. A closed wound was eventually achieved in all 30 patients, and sternal stability was restored in 29 patients. In the management of sternal dehiscence, the described technique of internal fixation can provide anatomic sternal reduction and stabilization, elimination of infection, and wound closure in a single-stage operation. Successful outcomes were achieved despite the presence of severe infection.     

Cranial morphological variation of Dromiciops gliroides (Microbiotheria) along its geographical distribution in south-central Chile: A three-dimensional analysis

We analyzed the variation in cranial morphology of the marsupial Dromiciops gliroides along its distribution in south-central Chile. We evaluated whether the cranial morphological variation is congruent with the phylogeographic structure previously observed in this species. We built three-dimensional models of 69 crania on which we digitized 30 landmarks. We used standard geometric morphometric methods to extract and analyze the shape and size components of the crania. Our data showed a subtle but consistent cranial size and shape variation along the studied distributional range, suggesting a geographic variation pattern rather than a phylogeographic structuring. Indeed, our multivariate analyses recovered a subtle morphological differentiation between island and mainland populations, contrary to what is suggested by a former phylogeographic study. We detected that either the cranial size variation, as well as the insularity and the latitude could be important factors underlying the cranial shape changes. We suggest that an interplay of historical and contemporary processes could be shaping the morphological pattern observed in this marsupial.     

The influence of size on body shape diversification across Indo‐Pacific shore fishes*

Understanding the causes of body shape variability across the tree of life is one of the central issues surrounding the origins of biodiversity. One potential mechanism driving observed patterns of shape disparity is a strongly conserved relationship between size and shape. Conserved allometry has been shown to account for as much as 80% of shape variation in some vertebrate groups. Here, we quantify the amount of body shape disparity attributable to changes in body size across nearly 800 species of Indo‐Pacific shore fishes using a phylogenetic framework to analyze 17 geometric landmarks positioned to capture general body shape and functionally significant features. In marked contrast to other vertebrate lineages, we find that changes in body size only explain 2.9% of the body shape variation across fishes, ranging from 3% to 50% within our 11 sampled families. We also find a slight but significant trend of decreasing rates of shape evolution with increasing size. Our results suggest that the influence of size on fish shape has largely been overwhelmed by lineage‐specific patterns of diversification that have produced the modern landscape of highly diverse forms that we currently observe in nature.     

Functional anatomy and adaptation of the third to sixth thoracic vertebrae in primates using three-dimensional geometric morphometrics

The morphology of the cranial thoracic vertebrae has long been neglected in the study of primate skeletal functional morphology. This study explored the characteristics of the third to sixth thoracic vertebrae among various positional behavioural primates. A total of 67 skeletal samples from four species of hominoids, four of cercopithecoids, and two of platyrrhines were used. Computed tomography images of the thoracic vertebrae were converted to a three-dimensional (3D) bone surface, and 104 landmarks were obtained on the 3D surface. For size-independent shape analysis, the vertebrae were scaled to the same centroid size, and the normalised landmarks were registered using the generalised Procrustes method. Principle components of shape variation among samples were clarified using the variance–covariance matrix of the Procrustes residuals. The present study revealed that the transverse processes were more dorsally positioned in hominoids compared to non-hominoids. The results showed that not only a dorsolaterally oriented but also a dorsally positioned transverse process in relation to the vertebral arch contribute to the greater dorsal depth in hominoids than in monkeys. The thoracic vertebrae of Ateles and Nasalis show relatively dorsoventrally low and craniocaudally long vertebrae with craniocaudally long zygapophyses and craniocaudally long base/short tip of the caudally oriented spinous process, accompanied by a laterally oriented and craniocaudally long base of the transverse process. Despite being phylogenetically separated, the vertebral features of Ateles (suspensory platyrrhine with its prehensile tail's aid) are similar to those of Nasalis (arboreal quadrupedal/jumping/arm-swing colobine). The morphology of the third to sixth thoracic vertebrae tends to reflect the functional adaptation in relation to positional behaviour rather than the phylogenetic characteristics of hominoids, cercopithecoids, and platyrrhines.

     

Sexing the human sternum

For differentiating a male from a female sternum, a metrical study of 400 adult North Indian sterna (312 males and 88 females) obtained from medicolegal postmortems was made. If the combined length of the manubrium and mesosternum was more than 140 mm. the sternum was male, and if less than 131 mm. it was female. No opinion could be given if the length was between 131 and 140 mm. By this measurement 72.12% male and 62.50% female sterna could be sexed with 100% accuracy. The length of the mesosternum alone could also determine the sex correctly in 50.32% male and 29.55% female specimens. The length of the manubrium, manubrium–corpus index, width of the first or third sternebra or their index, were not found to be useful in sexing a given sternum. By using multivariate analysis the probability of correctly identifying the sex of a sternum was over 85%.     

Principal components analysis of physical growth in savannah baboons

Morphometric data collected from 118 male and 169 female savannah baboons (Papio cynocephalus anubis) aged between birth and 5.5 years were analyzed to describe the morphology and physical growth of this species. Measurements included weight, crown-rump length, triceps circumference, and skinfolds at the neck, subscapular, suprailiac, and triceps anatomical sites. Principal components analyses were applied to the data to provide multivariate assessments of morphological patterning among the variables. These analyses resulted in the extraction of two unrotated orthogonal components that accounted for 88% of the overall sample variation. The first component accounted for 77% of the variation and represents an axis of overall body size. The second component represents an axis of shape variation that contrasts body size with fat patterning, and was interpreted as a measure of body leanness. Individual component scores were computed for determining age, gender, and age-by-gender interaction effects. Both components were found to be age dependent for both genders. Males and females shared similar age patterning along the two components; however, gender differences did occur in patterning along the two components; however, gender differences did occur in respect to leanness. The multivariate measure of overall body size increased for both genders similarly with advancing age. Age patterning along the leanness component was described as a decrease from birth to 1 year, followed by an increase in leanness in older ages. Females had a delayed and significantly less intense increase in leanness relative to males.     

Proposal of a thorax segment coordinate system for the 3D kinematical analysis of the cervical spine

The International Society of Biomechanics detailed the recommendations for 3D kinematics of intervertebral movements (Wu, et al. 2002. J Biomech. 35:543–548), but does not specify how to adapt this proposal to describe the kinematics of the cervical spine, between the head and the thorax. The analysis of the literature shows that no consensus exists at the present time on this subject. The objective of our study was to identify the reference points that formed the most rigid triplet allowing building an optimal thorax segment coordinate system (SCS). We thus measured the variations of distances between markers placed on various anatomical landmarks, and then the deformations of the combinations of three markers on different cervical movements of a sample of 10 asymptomatic subjects. The results show that the triplet formed by the sternum and both acromions undergoes less deformation on the flexion–extension movement. For all the other movements (lateral bending, axial rotation and complex movements), the triplet formed by sternum, T3 and TH (positioned on the thoracic spinal column, in a horizontal plane containing the sternal marker), undergoes less deformation. As a conclusion, the optimal triplet to define the thorax SCS for 3D kinematical analysis of the cervical spine is that formed by the markers: sternum, T3 and TH. This triplet makes it possible to define an orthonormal SCS, the axes of which coincide with anatomical directions, i.e. with the functional axes of the movement.     

Age-variability in body shape associated with excess weight: the UK National Sizing Survey

Background: The health risks of obesity are disproportionately due to central abdominal adiposity; however, the extent to which age is associated with the body shape of obese adults is not known. Objective: Three‐dimensional (3D) data on body shape from the UK National Sizing Survey were analyzed to investigate age‐associated changes in body shape within the BMI bands <20, 20–24.99, 25–29.99 and ≥30 kg/m². Methods: Measurements of anthropometry (weight and height) and a 3D body scan were obtained in 4,344 men and 5,266 women recruited from eight British cities. Results: The body shape of men showed high consistency within BMI bands between early adulthood and old age. In contrast, the body shape of women altered within each BMI band with increasing age. In obese, overweight, and normal weight women, age was associated with decreased thigh girth, increased waist, and bust girth. Whereas young obese women maintained an hourglass shape, in old age the body shape of obese women converged on that of obese men. Discussion: The association of age with body shape is markedly different between the sexes, with the impact of obesity on shape strongly age‐dependent in women but not in men. The age delay in the association between obesity and high waist girth in women may contribute to the sex‐difference in life expectancy. The relationship between body shape change and cardiovascular risk merits longitudinal investigation within individuals.     

Endocranial shape changes during growth in chimpanzees and humans: A morphometric analysis of unique and shared aspects

Compared to our closest living and extinct relatives, humans have a large, specialized, and complex brain embedded in a uniquely shaped braincase. Here, we quantitatively compare endocranial shape changes during ontogeny in humans and chimpanzees. Identifying shared and unique aspects in developmental patterns of these two species can help us to understand brain evolution in the hominin lineage.Using CT scans of 58 humans and 60 chimpanzees varying in age from birth to adulthood, we generated virtual endocasts to measure and analyze 29 three-dimensional endocranial landmarks and several hundred semilandmarks on curves and the endocranial surface; these data were then analyzed using geometric morphometric methods.The ontogenetic shape trajectories are nonlinear for both species, which indicates several developmental phases. Endocranial shape is already distinct at birth and there is no overlap between the two species throughout ontogeny. While some aspects of the pattern of endocranial shape change are shared between humans and chimpanzees, the shape trajectories differ substantially directly after birth until the eruption of the deciduous dentition: in humans but not in chimpanzees, the parietal and cerebellar regions expand relatively (contributing to neurocranial globularity) and the cranial base flexes within the first postnatal year when brain growth rates are high. We show that the shape changes associated with this early “globularization phase” are unique to humans and do not occur in chimpanzees before or after birth.