A simple univariate technique for determining sex from fragmentary femora: its application to a Scottish short cist population

A simple univariate technique for sexing individuals represented by fragmentary skeletal remains is described. The results obtained were highly consistent (about 90%) with those obtained by conventional analysis of pelvic and cranial morphology. It is suggested that using maximum anteroposterior diameter of the femoral shaft as a sex discriminator has advantages over midshaft circumference even when intact femora are available.     

Evolution of hindlimb bone dimensions and muscle masses in house mice selectively bred for high voluntary wheel‐running behavior

We have used selective breeding with house mice to study coadaptation of morphology and physiology with the evolution of high daily levels of voluntary exercise. Here, we compared hindlimb bones and muscle masses from the 11th generation of four replicate High Runner (HR) lines of house mice bred for high levels of voluntary wheel running with four non‐selected control (C) lines. Mass, length, diameter, and depth of the femur, tibia‐fibula, and metatarsal bones, as well as masses of gastrocnemius and quadriceps muscles, were compared by analysis of covariance with body mass or body length as the covariate. Mice from HR lines had relatively wider distal femora and deeper proximal tibiae, suggesting larger knee surface areas, and larger femoral heads. Sex differences in bone dimensions were also evident, with males having thicker and shorter hindlimb bones when compared with females. Several interactions between sex, linetype, and/or body mass were observed, and analyses split by sex revealed several cases of sex‐specific responses to selection. A subset of the HR mice in two of the four HR lines expressed the mini‐muscle phenotype, characterized mainly by an ～50% reduction in hindlimb muscle mass, caused by a Mendelian recessive mutation, and known to have been under positive selection in the HR lines. Mini‐muscle individuals had elongated distal elements, lighter and thinner hindlimb bones, altered 3rd trochanter muscle insertion positions, and thicker tibia‐fibula distal widths. Finally, several differences in levels of directional or fluctuating asymmetry in bone dimensions were observed between HR and C, mini‐ and normal‐muscled mice, and the sexes. This study demonstrates that skeletal dimensions and muscle masses can evolve rapidly in response to directional selection on locomotor behavior.     

Mechanical advantages of the Neanderthal thumb in flexion: a test of an hypothesis

It has been proposed that the pollical phalangeal length proportions of the Neanderthals provided them with a greater mechanical advantage relative to recent humans for their pollical flexor muscles in power grips across the interphalangeal (IP) joint at the expense of the mechanical advantage of those pollical flexor muscles in precision grips at the finger tip. To test these related hypotheses, we compared the pollical load arm dimensions (phalanx lengths) to power arm dimensions (dorsopalmar articular heights) for the European and Near Eastern Neanderthals and for European and Amerindian samples of recent humans. It was found, initially, that the proximal articular height of the pollical distal phalanx is a poor predictor of the power arm at the IP articulation, even though the proximal articular height of the pollical proximal phalanx was an adequate indicator of the power arm size at the metacarpophalangeal (MCP) joint. In addition, differences in distal pollical ulnar deviation at the IP joint appeared to make little difference in the mechanical advantage comparisons. More importantly, the relative shortness of Neanderthal proximal pollical phalanges and the relative lengthening of their distal pollical phalanges was confirmed, and it was determined that, despite some minor differences in articular dimensions between Neanderthals and recent humans, these pollical phalangeal length contrasts translated into significant differences in mechanical advantages for the flexor muscles across the MCP and IP articulations.     

Estimating body mass in subadult human skeletons

Methods for estimating body mass from the human skeleton are often required for research in biological or forensic anthropology. There are currently only two methods for estimating body mass in subadults: the width of the distal femur metaphysis is useful for individuals 1–12 years of age and the femoral head is useful for older subadults. This article provides age‐structured formulas for estimating subadult body mass using midshaft femur cross‐sectional geometry (polar second moments of area). The formulas were developed using data from the Denver Growth Study and their accuracy was examined using an independent sample from Franklin County, Ohio. Body mass estimates from the midshaft were compared with estimates from the width of the distal metaphysis of the femur. Results indicate that accuracy and bias of estimates from the midshaft and the distal end of the femur are similar for this contemporary cadaver sample. While clinical research has demonstrated that body mass is one principle factor shaping cross‐sectional geometry of the subadult midshaft femur, clearly other biomechanical forces, such as activity level, also play a role. Thus formulas for estimating body mass from femoral measurements should be tested on subadult populations from diverse ecological and cultural circumstances to better understand the relationship between body mass, activity, diet, and morphology during ontogeny. Am J Phys Anthropol 143:146–150, 2010. © 2010 Wiley‐Liss, Inc.     

The stiffness characteristics of hybrid Ilizarov fixators

The use of hybrid Ilizarov models around femoral area is gaining clinical popularity lately. Hybrid systems show different mechanical properties. The purpose of this report is to examine the stiffness characteristics of the C-arch and half-pins on the hybrid Ilizarov fixators. Eight models that included standard Ilizarov and hybrid models were applied to six femoral sawbones. The distal part of fixation was composed of a two-ring frame applied identically to all bones. The difference of the configuration was at the proximal part, where half-pins with or without C-arches were either added to the proximal two-ring frame or replaced the proximal one- or two-ring frame. Osteotomy was performed in the femoral diaphysis and the bone was distracted 2cm. The stability of the system was tested with the axial compression testing machine. Displacements between the adjacent fracture sides were measured with the video extensometer in three dimensions. We found that proximal half-pin applications alone had less stiffness, but half-pins with C-arch had more stiffness than the model including only half-pins. Additional half-pins onto one- or two-ring frames had more longitudinal stiffness, but this system showed weak resistance against transverse displacement.     

Development of epiphyseal structure and function in Didelphis virginiana (Marsupiala,Didelphidae)

This study addressed the question of how the epiphyses of growing mammals change their external shape and internal architecture during postnatal development. Ontogenetic transformations in the external form and internal structure of the fore‐ and hindlimb epiphyses were examined in a mixed cross‐sectional sample of Didelphis virginiana using two methods: morphometric analysis of linear epiphyseal dimensions and histological staining of serially sectioned epiphyses. Metric data indicate that Virginia opossums are born with relatively short hindlimbs and long forelimbs, but by the time they are weaned their hindlimbs are longer than their forelimbs. Functional integration of the locomotor system in D. virginiana involves a decoupling of fore‐ and hindlimb growth rates so that between birth and weaning, femoral length, diaphyseal cross‐sectional area, and articular surface area increase at a significantly faster rate than the corresponding humeral dimensions. Histological results demonstrate that these differences in growth rate are reflected in morphology of the humeral and femoral growth plate and epiphyseal cartilages. The humeral cartilages exhibit a level of cellular organization characteristic of more mature limb elements at earlier developmental stages compared to the femoral cartilages, which assume this anisotropic structure relatively later in postnatal development. Results presented here also reveal that the formation of articular cartilage and the initiation of epiphyseal ossification in D. virginiana are both correlated with the development of independent positional behaviors prior to weaning. These histological data, therefore, suggest that mechanical loading associated with the postnatal onset of locomotor and postural development may provide an important stimulus for the progression of ossification and the formation of articular cartilage in the epiphyses of growing mammals. J. Morphol. 239:283–296, 1999. © 1999 Wiley‐Liss, Inc.     

Sex determination of prehistoric central California skeletal remains using discriminant analysis of the femur and humerus

A large sample (n = 370) of Central California prehistoric skeletal remains was analyzed for sexual dimorphism of long bones using nine femoral and nine humeral dimensions. Sex of all individuals was assessed using traits of the os pubis. Discriminant analysis was done separately for the robust Early Horizon sample and the Middle/Late Horizon sample. Use of multiple variables did not produce appreciably better results over the use of several of the best variables, analyzed singly. Attention is focused on measurements of maximum diameter femoral head, femoral bicondylar width, and diameter of the humeral head (transverse or vertical). These variables produce excellent separation of the sexes with about 90% accuracy for the Middle/Late Horizon sample. They have been overlooked in the recent literature in which the relative values of length versus midshaft dimensions are debated. The measurements found to be superior in this study are taken at the ends of the bones where durability of these regions is indicated by large sample sizes found in this study. We suggest workers redirect their focus from the midshaft to the ends of the long bones. The discriminant analyses presented here have greater accuracy than most claims for either long bone or cranial sex determination. These standards, based on two samples with differing robusticity, may have applicability for workers in other areas who lack large skeletal samples.     

西安地区现代人胫骨的人类学研究

本文对西安地区现代成人胫骨100副(男50,女50)进行了人类学的研究。按马丁方法测量了胫骨全长、髁踝长,上下段宽,上内侧和上外侧关节面的矢径,下段矢径,滋养孔平面最大横径和矢径,体最小周径和胫骨扭转角。计算出胫骨指数,长厚指数和胫股指数。并对一些数据进行了种族和地区的对比。     

A new method for assessing the sex of fragmentary skeletal remains: femoral shaft circumference

A simple discriminant function using midshaft femoral circumference for the determination of sex has been tested with 114 skeletons from the Libben Site, Ontario County, Ohio. The results have been shown to be 85% consistent with other, accepted means of determining sex. Femur circumference an be an aid to the sexual identification of poorly preserved and fragmentary skeletal remains.     

Articular constraint, handedness, and directional asymmetry in the human second metacarpal

The hypothesis that functional adaptation of joint surfaces to mechanical loading occurs primarily through change in mass, density, and structure of subarticular trabeculae (the "articular constraint" model) is investigated through an analysis of directional asymmetry among three separate bone compartments in the human second metacarpal. Measures of midshaft cross-sectional geometry, osteometry of the distal epiphysis, and subarticular trabecular microarchitecture of the distal epiphysis (assessed by high-resolution microcomputed tomography) were determined for 29 paired male and female metacarpals from a well-preserved nineteenth-century Euro-Canadian historic cemetery sample. For each measure, asymmetry was quantified using both mean-difference and confidence-interval methods. Both methods found a significant right-hand bias for measures of structural strength in midshaft geometry, as has been previously noted for this sample. Articular size, however, exhibits a right-hand bias only with regard to mediolateral, and not dorsopalmar, dimensions, a result that may reflect directional asymmetry in hand breadth at the distal palmar arch. The most striking asymmetries occur for subarticular trabecular microarchitecture. The right metacarpal head exhibits greater bone volume fraction, bone surface density, trabecular number, connectivity, and a more platelike rather than rodlike structure. These outcomes confer greater resistance to both axial compressive and shear strains for the metacarpal head at the metacarpophalangeal arthrosis. In all, these results confirm and extend previous research documenting structural asymmetries and limb dominance and are consistent with the concept of articular constraint. They also suggest a morphological signal through which functional asymmetry associated with handedness in fossil hominins may be investigated.     

Classification and misclassification in sexing the Black femur by discriminant function analysis

Stepwise discriminant function analysis for sex assessment was applied to 130 North American Black femora. The measurements included femoral length and three midshaft dimensions likely to be preserved in archaeologically derived and forensic remains. The method correctly assigned sex for 76.4% of the sample (range 70.8–81.5%). This compares favorably with results achieved with other skeletal parts; it also compares favorably with results using the femur in sexing other racial groups. Among our other conclusions are: (1) a “general size factor” is one of major significance in correct classification and in misclassification of sex, and most misclassified individuals are anomalous for this factor; (2) the inconsistency in the relation between circumference and femoral length, which characterizes the remaining misclassified individuals, suggests that anomalous functional demands of body weight/musculature are at fault, and affect circumference more than length; and (3) discriminant function analysis of the same variables in Whites produced similar results, suggesting that sex overrides race in sex assessment; this was confirmed by cross-validating the predictive accuracy of Black discriminant function coefficients on White data, and vice versa.     

Neandertal scapular glenoid morphology

Analysis of Neandertal and recent human scapular glenoid fossae reveals that the former had long, narrow, and flat glenoid articular surfaces relative to those of modern humans. Comparison of glenoid length, breadth, and curvature to humeral articular dimensions demonstrates that Neandertal glenoid length and curvature scale to proximal and distal humeral articular dimensions in the same manner as those of modern humans. The remaining contrast is in the relatively greater glenoid fossa width seen in modern humans. This difference in morphology implies differences in the habitual degree of dorsoventral glenohumeral movement between Neandertals and modern humans. This in turn may be related to contrasts in tool use, especially with respect to throwing and projectile use.     

Discrepancies in knee joint moments using common anatomical frames defined by different palpable landmarks

The aim was to investigate the effects of three anatomical frames using palpable anatomical landmarks of the knee on the net knee joint moments. The femoral epicondyles, femoral condyles, and tibial ridges were used to define the different anatomical frames and the segment end points of the distal femur and proximal tibia, which represent the origin of the tibial coordinate system. Gait data were then collected using the calibrated anatomical system technique (CAST), and the external net knee joint moments in the sagittal, coronal, and transverse planes were calculated based upon the three anatomical frames. Peak knee moments were found to be significantly different in the sagittal plane by approximately 25% (p 相似文献   

Relative growth rates of limb muscles in the diprotodont marsupial, Setonix brachyurus

The fore- and hindlimb muscles of 12 Setonix brachyurus joeys, aged 5 to 175 days postpartum, and four adults were dissected out and weighed. Individual muscles and muscle groups were analysed for absolute and relative growth changes. From comprising almost 59% of the total limb musculature at birth the forelimb muscles finally constitute just over 9% in the adult; the hindlimb muscles start at just over 41% and end at almost 91%. In both limbs, the extensor actions predominate in the proximal limb segment because of their propulsive functions, whereas in the distal segment the flexor muscles tend to be the larger because of their shock-absorbing and spring functions. During growth of the fore-limb there is a relative increase in the size of latissimus dorsi and triceps brachii and a decrease in the distal segment muscles; in the hindlimb the gluteal and hamstring muscles increase at the expense of the distal segment muscles. Specializations for speed include long distal hindlimb segments and proximally located muscle bellies. The above findings reflect the adaptations and changing locomotor patterns from birth to adult in the Quokka.     

Hunter-gatherer postcranial robusticity relative to patterns of mobility, climatic adaptation, and selection for tissue economy

Human skeletal robusticity is influenced by a number of factors, including habitual behavior, climate, and physique. Conflicting evidence as to the relative importance of these factors complicates our ability to interpret variation in robusticity in the past. It remains unclear how the pattern of robusticity in the skeleton relates to adaptive constraints on skeletal morphology. This study investigates variation in robusticity in claviculae, humeri, ulnae, femora, and tibiae among human foragers, relative to climate and habitual behavior. Cross-sectional geometric properties of the diaphyses are compared among hunter-gatherers from southern Africa (n = 83), the Andaman Islands (n = 32), Tierra del Fuego (n = 34), and the Great Lakes region (n = 15). The robusticity of both proximal and distal limb segments correlates negatively with climate and positively with patterns of terrestrial and marine mobility among these groups. However, the relative correspondence between robusticity and these factors varies throughout the body. In the lower limb, partial correlations between polar second moment of area (J(0.73)) and climate decrease from proximal to distal section locations, while this relationship increases from proximal to distal in the upper limb. Patterns of correlation between robusticity and mobility, either terrestrial or marine, generally increase from proximal to distal in the lower and upper limbs, respectively. This suggests that there may be a stronger relationship between observed patterns of diaphyseal hypertrophy and behavioral differences between populations in distal elements. Despite this trend, strength circularity indices at the femoral midshaft show the strongest correspondence with terrestrial mobility, particularly among males.     

Late pleistocene human femoral diaphyseal curvature

Anterior femoral curvature is a consistent characteristic of Pleistocene and recent humans, although variation exists in the degree of curvature among individuals and across populations. In particular, one group, the Neandertals, has been characterized for a century as having marked femoral curvature. To evaluate the degree of anterior femoral curvature in both Neandertals and other Late Pleistocene humans, their curvature subtenses and proximodistal positions were evaluated in the context of recent human variation. Recent human comparisons show little relationship between subtense (absolute curvature) and femoral length, suggesting that an index that incorporates subtense relative to the length of the femur is inappropriate for between-group assessments. Neandertals were statistically indistinguishable from Middle or earlier Upper Paleolithic modern humans in the degree of absolute curvature, all of whom had greater curvature on average than all later humans. Additionally, Neandertals and Qafzeh-Skhul early modern humans had a more distal point of maximum curvature than any other group. Curvature was not strongly correlated with functional considerations including body mass estimates, surrogate variables for body size, proximal femoral articular orientation, or knee anteroposterior dimensions. The functional role of femoral anterior curvature is unknown; however, the general decrease in curvature subtense closely parallels the between-group changes in inferred levels of mobility from femoral diaphyseal robusticity and shape, suggesting that femoral curvature may reflect mobility levels and patterns among Late Pleistocene and recent humans.     

Comparative skeletogenesis of the forearm of the little brown bat (Myotis lucifugus) and the Norway rat (Rattus norvegicus).

This study describes, quantifies, and compares the growth and development of the volant forelimb morphology of Myotis lucifugus with that of the terrestrial forelimb morphology of Rattus norvegicus. In M. lucifugus there is 1) accelerated growth in forearm length after parturition, 2) cessation in growth of the midshaft diameter of the ulna just after the onset of osteogenesis, 3) proximal fusion of the radius and ulna, which results in the radius occupying 97% of the articular surface of the elbow joint in adults, 4) fusion between the cartilaginous distal epiphyses of the radius and ulna which results in formation of a radioulnar bridge that becomes fully ossified in adults, and 5) incomplete ossification of the ulna with a section of the diaphysis becoming ligamentous. None of these events occurs during development in R.norvegicus.     

Titanium Elastic Nail (TEN) versus Reconstruction Plate Repair of Midshaft Clavicular Fractures: A Finite Element Study

BackgroundThe biomechanical characteristics of midshaft clavicular fractures treated with titanium elastic nail (TEN) is unclear. This study aimed to present a biomechanical finite element analysis of biomechanical characteristics involved in TEN fixation and reconstruction plate fixation for midshaft clavicular fractures.MethodsFinite element models of the intact clavicle and of midshaft clavicular fractures fixed with TEN and with a reconstruction plate were built. The distal clavicle displacement, peak stress, and stress distribution on the 3 finite element models were calculated under the axial compression and cantilever bending.ResultsIn both loading configurations, TEN generated the highest displacement of the distal clavicle, followed by the intact clavicle and the reconstruction plate. TEN showed higher peak bone and implant stresses, and is more likely to fail in both loading configurations compared with the reconstruction plate. TEN led to a stress distribution similar to that of the intact clavicle in both loading configurations, whereas the stress distribution with the reconstruction plate was nonphysiological in cantilever bending.ConclusionsTEN is generally preferable for treating simple displaced fractures of the midshaft clavicle, because it showed a stress distribution similar to the intact clavicle. However, TEN provides less stability, and excessive exercise of and weight bearing on the ipsilateral shoulder should be avoided in the early postoperative period. Fixation with a reconstruction plate was more stable but showed obvious stress shielding. Therefore, for patients with a demand for early return to activity, reconstruction plate fixation may be preferred.     

Training increases muscle blood flow in rats with peripheral arterial insufficiency

This study investigated the effect of physical training on muscle blood flow (BF) in rats with peripheral arterial insufficiency during treadmill running. Bilateral stenosis of the femoral artery of adult rats (300-350 g) was performed to reduce exercise hyperemia in the hindlimb but not limit resting muscle BF. Rats were divided into normal sedentary, acute stenosed (stenosed 3 days before the experiment), stenosed sedentary (limited to cage activity), and stenosed trained (run on a treadmill by a progressively intense program, up to 50-60 min/day, 5 days/wk for 6-8 wk). Hindlimb BF was determined with 85Sr- and 141Ce-labeled microspheres at a low (20 m/min) and high treadmill speed (30-40 m/min depending on ability). Maximal hindlimb BF was reduced to approximately 50% normal in the acute stenosed group. Total hindlimb BF (81 +/- 5 ml.min-1.100 g-1) did not change in stenosed sedentary animals with 6-8 wk of cage activity, but a redistribution of BF occurred within the hindlimb. Two factors contributed to a higher BF to the distal limb muscle of the trained animals. A redistribution BF within the hindlimb occurred in stenosed trained animals; distal limb BF increased to approximately 80% (P less than 0.001) of the proximal tissue. In addition, an increase in total hindlimb BF with training indicates that collateral BF has been enhanced (P less than 0.025). The associated increase in oxygen delivery to the relatively ischemic muscle probably contributed to the markedly improved exercise tolerance evident in the trained animals.     

Hand and foot remains from the Gran Dolina Early Pleistocene site (Sierra de Atapuerca, Spain).

We report here the study of the 22 hand and foot remains from the Early Pleistocene level TD6 of the Gran Dolina site at Sierra de Atapuerca (Burgos, Spain) recovered from 1994 to 1996. These remains are paratypes of Homo antecessor. All of the elements are briefly described and compared with other fossil hominids. The capitate has a constricted neck, well developed head, strong attachment for the ligamentum interosseum trapezoid-capitate, a palmarly placed trapezoid facet with a distinctive small dorsal trapezoid facet, a highly curved and oblique orientation of the second metacarpal facet, and a transversally oriented dorsodistal border. A hamate with a moderately projecting and lightly built hamulus; an inferred reduced styloid process on the third metacarpal base; a wide second metacarpal head; and middle phalanges with well marked insertions for the flexor digitorum superficialis muscle and wide heads. The morphology and dimensions of the pedal remains from TD6 are very similar to modern humans; but the base, proximal articular surface and shafts of the proximal hallucal phalanges are more rounded and the midshaft of the proximal toe phalanx is wider.