Morphological asymmetries in Southern African populations. Further evidence for lateralization

Both femora of 364 individuals of southern African tribes and South Africans of European origin were analysed for population and side differences. Emphasis was placed on multivariate analyses, although uni-and bivariate statistics were also employed and discussed. While the latter analyses did not provide conclusive results, all multivariate tests were highly significant and demonstrated that differences between samples were predominantly due to shape variability, especially of the proximal part of the femur. Among southern African Negroes a morphological gradient seemed to be apparent between Sothos, Zulus and Xosas following a clinal pattern. Differences between southern African tribes and Europeans were marked, but may, at least in part, be accounted for by different environmental factors and activity levels. Side differences of femora were found to be pronounced in all populations studied and also showed a comparable morphological pattern between the samples. The left femur was generally more robust than the right indicating that it was better suited to withstand axial forces and medio-lateral bending. Thus, the findings lend support to the hypothesis that there exist a universal pattern of lateralization, whereby the left lower limb is commonly used for weight-bearing while the right one is more likely used for motor-tasks.     

The distribution of breaking strength in the human femur shaft

703 standardized test specimens of dry cortical bone from different shaft regions of human femora were subjected to compression till failure parallel to the long axis of the shaft. The rate of load increase was 50 kg/cm²/sec. The significance of four sources of variation was tested, i.e. cross-sectional area (site), quadrant (position), side of the body, and individual, in three analyses of variance. All main effects and the interactions site x position, site x individual, position x individual, body side x individual are significant. A constant pattern of strength distribution in the proximal three cross-sectional areas is shown: this pattern is changed in the two distal cross-sectional areas, but it is the same on the left and right sides of the body apart from variations by the main effects. The pattern of strength distribution in the two distal cross-sectional areas probably changes with age. The distributions of mean compressive strength of femur shafts from two age groups are presented diagrammatically in Fig. 1, and the respective means are given in Fig. 2.     

Directional asymmetry in the forelimb of Macaca mulatta

Asymmetry was investigated in the forelimbs of 150 rhesus monkey (Macaca mulatta) skeletons using measurements of right and left humerii, radii, ulnae, second metacarpals, and femora. Seven of the ten forelimb dimensions were larger on the right than on the left side. Paired t-tests revealed that the mean of the right side was significantly larger than that for the left for two measurements of the ulna and two of the humerus. No measurement was significantly larger on the left than on the right side. These results indicate a small but significant asymmetry in the forelimb bones of rhesus monkeys and, as is the case for humans, the direction of asymmetry favors the right side. Our findings are consistent with an interpretation of hypertrophy of certain muscles and opens the question of whether rhesus monkeys preferentially use their right forelimbs for manipulative tasks that require manual dexterity, as is the case for humans. These forelimb skeletal asymmetries are discussed in light of the recent literature on cortical asymmetry and handedness in nonhuman primates.     

Taxonomic affinities of the Eppelsheim femur

The taxonomic affinities of the Eppelsheim femur, known as Paidopithex, have been unclear for more than a century. Over the years, due to similarities with Pliopithecus, some authors have considered it a large pliopithecid, while others refer to it as Dryopithecus. The issue could not be resolved, because no definitive Dryopithecus femora were available. With the discovery of the Dryopithecus laietanus skeleton from Can Llobateres (CLl 18800), it has become possible to test the attribution of the Eppelsheim femur to Dryopithecus on the basis of direct morphological and metrical comparisons. By means of allometric techniques, we show that the Eppelsheim and D. laietanus femora fit different hindlimb morphologies with regard to relative length and relative head/neck size, with Paidopithex significantly differing from Dryopithecus, but more closely resembling Pliopithecus. Paidopithex also differs from Dryopithecus in other important aspects, such as its lower neck/shaft angle, lack of elevation of the femoral head above the greater trochanter, more posteriorly oriented lesser trochanter, and proximal shaft diameter thicker anteroposteriorly than mediolaterally. In these features, Paidopithex most closely resembles Pliopithecus in spite of differences in body mass (ca. 22 kg vs. ca. 10 kg, respectively). These features suggest that Paidopithex used a primitive locomotor pattern associated with arboreal quadrupedalism, instead of the more derived pattern displayed by Dryopithecus. Currently available evidence confirms that the attribution of Paidopithex to Dryopithecus can be rejected. Paidopithex could be a large and otherwise unknown pliopithecid, but the possibility cannot be ruled out that it represents a third kind of catarrhine.     

Terrestrial locomotion in pterosaurs

On the basis of a well‐preserved pelvis of Anhanguera sp. from the Lower Cretaceous (Aptian) of the Chapada do Araripe, Brazil, the problem of terrestrial locomotion in pterosaurs is discussed. A three‐dimensional reconstruction of the pelvis led to a lateral, dorsal and posterior orientation of the acetabula. By use of the preserved proximal ends of the femora of the same individual, the articulation in the hip socket could be tested. The normal articulation of the femur resulted in a horizontal position of the femur shaft, probably during flight. For constructional reasons the femur could not be brought down to a vertical position. Therefore, a parasagittal swing of the femora necessary for a bird‐like stance and gait must have been impossible. It is suggested that in pterosaurs the wing membrane was attached to the upper leg, which helped in stretching, steering and cambering.

Moreover, on the basis of comparisons of the fossil preservation of pterosaurs Compsognathus and Archaeopteryx in the Solnhofen limestone, it is concluded that the femora of pterosaurs were splayed out laterally, and that they had a semi‐erect gait. They were not bipedal animals, but had to use their fore limbs as well on the ground. Nevertheless, as vertebrates extremely adapted to flight, they could not have been able quadrupeds, either.     

Three-point bending and acoustic emission study of adult rat femora after immobilization and free remobilization

The experiment concerned effects of immobilization and remobilization on mechanical properties of femoral shaft. Twenty-four weeks old male rats were used: two groups (I3 and I3R4) with the right hindlimb immobilized for 3 weeks by taping, and one control (C). In I3R4 immobilization was followed by 4 weeks of free remobilization. Mechanical properties in three-point bending, mass, geometry, and mineralization of bone tissue were measured post mortem in both femora in I3 and I3R4 and in right femora in control. Acoustic emission signals (AE) were recorded during the bending test. The right femora in I3, I3R4 and C did not differ significantly in size, mass and mineralization (ANOVA). The differences were significant considering mechanical parameters and AE signals. In I3 yield bending moment and stiffness were lower (p=0.013 and 0.025) and deflection was larger (p=0.030) than in C. In I3R4 maximum bending moment, yield moment, stiffness and work to failure were lower than in C (p=0.013, 0.009, 0.032, and 0.005). Paired t-test showed that remobilization resulted in worsening of properties of right femora. Side-to-side differences in I3R4 were more pronounced than in I3. Moreover, AE signals from the right femora were more numerous and burst type than from the left. The results demonstrate that strength of bone decreases during the first period of free remobilization. The decrease is accompanied by a significant decrease of bone toughness. The AE data support the hypothesis that immobilization-related degradation of bone mechanical properties is associated with increasing brittleness of cortical bone tissue.     

Asymmetry of Leg Use During Prey Handling in the Spider Scytodes globula (Scytodidae)

In spitting spiders Scytodes globula collected in the field, anterior leg loss was more frequent on the left than on the right side, possibly as an outcome of predatory episodes. A laboratory study was performed in which intact adult females of S. globula were placed with individuals from three species of recluse spiders, Loxosceles intermedia, L. gaucho, and L. laeta. The frequency of probing touches by spitting spiders to their prey was significantly higher with left leg I than with right leg I. Left leg II and right leg II also differed in touching frequency, but in a less marked way. The results, which may represent the first evidence of behavioral laterality in a spider species, suggest that behavioral asymmetry may be an ancient evolutionary trait.     

The anomalous archaic Homo femur from Berg Aukas, Namibia: a biomechanical assessment.

The probably Middle Pleistocene human femur from Berg Aukas, Namibia, when oriented anatomically and analyzed biomechanically, presents an unusual combination of morphological features compared to other Pleistocene Homo femora. Its midshaft diaphyseal shape is similar to most other archaic Homo, but its subtrochanteric shape aligns it most closely with earlier equatorial Homo femora. It has an unusually low neck shaft angle. Its relative femoral head size is matched only by Neandertals with stocky hyperarctic body proportions. Its diaphyseal robusticity is modest for a Neandertal, but reasonable compared to equatorial archaic Homo femora. Its gluteal tuberosity is relatively small. Given its derivation from a warm climatic region, it is best interpreted as having had relatively linear body proportions (affecting proximal diaphyseal proportions, shaft robusticity, and gluteal tuberosity size) combined with an elevated level of lower limb loading during development (affecting femoral head size and neck shaft angle).     

卡车与卡车前部碰撞驾驶员与前排乘车人损伤特征的研究

目的：研究道路交通事故卡车与卡车前部碰撞驾乘人员损伤特征,分析比较驾乘人员的损伤及损伤分布特点。方法：应用统计学方法对2001年-2010年昆明地区卡车与卡车200例前部碰撞人员损伤的法医学鉴定资料进行系统分析性研究。结果：1.驾驶员易发生损伤的部位是下肢、头颈部,其次为胸、腹部损伤。驾驶员易发生右下肢的损伤及骨折。驾驶员易发生颅骨骨折和肋骨骨折。2.前排乘车人员易发生损伤的部位是上肢、头颈部,其次为下肢,而胸腹部损伤较少见。前排乘车人员易发生上肢的损伤及双侧尺桡骨的骨折。前排乘车人员左侧头颈部受伤的几率大于驾驶员的相对部位。前排乘车人员易发生右肱骨骨折。结论：1.与前排乘车人相比,驾驶员易造成胸部、腹部及盆部、右侧下肢的损伤及右股骨胫腓骨的骨折,发生双侧上肢的体表损伤及尺桡骨骨折均明显少。在身体体表出现胸部、腹部及盆部多部位连续的损伤,有助于提高认定卡车驾驶员的准确性。2.与驾驶员相比,前排乘车人易形成左侧头颈部的损伤,上肢双侧尺桡骨骨折,右侧肱骨的骨折。当损伤位于身体左侧头颈部且有右侧肱骨的骨折,有助于提高认定卡车前排乘车人的准确性。     

Biomechanical properties of tendons during lower-leg lengthening in dogs using the Ilizarov method.

Ten dogs were provided with a circular fixator. Segment resection of the fibula and tibial osteotomy in the right lower leg was performed. 5 days after surgery, a lengthening of the right lower leg by 2.5 cm was performed on 6 dogs using a distraction rate of 0.5 mm, twice per day. 3 dogs with leg lengthening and 2 dogs of the control group without leg lengthening were sacrificed at the end of the distraction phase of 25 days and the remaining dogs after another 25 days. Postmortally the tendons of the tibialis anterior, extensor digitorum longus, peroneus longus and the achilles tendon were taken from the operated right side and the left non-operated control side and were examined biomechanically in cyclic tests. The control group without lengthening showed no changes in the biomechanical properties in the tendons of either side nor in those of the unlengthened left side of the operated dogs. In contrast the biomechanical tests revealed a marked decrease of the elastic modulus, an increase of distraction length and an increase of modulus reduction on the lengthened side compared to the non-operated left side.     

The effects of stress on cortical bone thickness in rodents

The right and left femora of three groups of rodents, cold stressed, noise stressed, and heat stressed, were sectioned transversely at the most inferior point of the third trochanter. Cortical bone thickness of the proximal section for all three groups was determined by measuring an enlargement obtained with a Wild stereo microscope with a camera lucida drawing attachment. Cold stressed animals were found to have significantly thinner cortical bone than did controls, noise stressed animals did not differ from controls, and heat stressed animals had thinner cortical bone than did controls. It is concluded that stress may be responsible for the thinner cortex of cold and heat stressed animals, but that other factors may be at work and that it is not possible to tell whether different types of stress act through the same or through different mechanisms.     

Anthropometric studies of the long bones of the "shell mound" Indians

The “shell mound” Indians exhibit both sexual and bilateral variations in comparative long bone lengths. Mean long bone lengths are shortest in the Indian group when compared to those reported for both Caucasians and Negroes. The radiohumeral and humero-femoral indices of the “shell mound” Indians are higher than those reported for either Caucasians or Negroes. There is a relatively high degree of anterior-posterior curvature of the femur in the Indian group when compared to the femora of Caucasian and Negroes. There is apparently no correlation between maximum femoral length and trochanter length in comparing right and left sides in either sex. The collo-diaphyseal angles are greater on the average on the left side in both sexes. The femora of male “shell mound” Indians exhibits greater average collo-diaphyseal angles than do the femora of male Caucasians.     

Setal entanglement: an undescribed method of stridulation by a neotropical tarantula (Araneae: Theraphosidae)

The theraphosid spider Theraphosa leblondi (Latreille) produces a sibilant, hissing sound during defensive displays. This sound is produced using a previously undescribed method of stridulation: setal entanglement. The opposing surfaces of the femora of the pedipalps, first, and second pair of legs are clothed in unique setae which have their distal portion bearing hooks and a shaft clothed in filaments. Experimental ablations described here showed these plumose setae to be the site of sound production. Based on examination of the fine structure of these setae, we propose that the hissing sound is produced by the entanglement and pulling apart of the hooks at the ends of the setae on one leg surface and the long, plumose filaments on the median part of the setae on the opposing leg surface. Evidence presented suggests that this is a case of an acoustic aposematic display directed at vertebrate predators.     

Disuse-induced deterioration of bone strength is not stopped after free remobilization in young adult rats

The effect of unilateral hindlimb immobilization and subsequent free remobilization on mechanical properties of femur was examined in young adult rats. Right hindlimb of 17 weeks old male rats was immobilized for 2 weeks. Rats were sacrificed either directly after immobilization (E0) or after 4 weeks of free remobilization (E4). Mechanical properties in three-point bending as well as dry mass (m_dry), geometry, apparent density (d_app), and mineralization of dry bone tissue were measured post mortem in right and left femora of experimental rats (E0, E4) and in right femora of age-matched controls (C0, C4). Differences between right femora of experimental and control animals and between right and left femora of experimental animals were analyzed. After immobilization only d_app in E0 was significantly lower than in C0. Side-to-side differences in E0 were present only in m_dry and d_app. Surprisingly, 4 weeks after remobilization the differences between experimental and control femora were more pronounced. Mineralization, d_app, maximum bending moment (M_max), yield bending moment (M_y) and stiffness of the right femur were lower in E4 than in age-matched C4. Side-to-side differences in remobilized rats (E4) were still significant for m_dry and d_app. Additionally, the medullary area was larger, and M_max, M_y, stiffness and work to failure were lower in the right femur than in the left. It is concluded, that the processes of bone deterioration initiated during immobilization do not cease immediately after resumption of normal mechanical loading.     

Osteology and relationships of a new theropod dinosaur from the Middle Jurassic of Patagonia

Abstract:  A new taxon of theropod dinosaur is described as Condorraptor currumili gen. et sp. nov., from the Middle Jurassic (Callovian) Cañadón Asfalto Formation of Chubut Province, Argentinean Patagonia. The taxon is represented by a single fragmentary postcranial skeleton. Although incompletely known, Condorraptor is the second most complete theropod from the Middle Jurassic of Gondwana. The new taxon is characterized by the absence of a posterior incision between the fibular condyle and the medial side of the proximal articular end of the tibia, the pleurocoels in the anterior cervicals being situated posteroventral to the parapophyses, and the presence of a pronounced 'step' between the distal articular facet and shaft of Mt IV. Pneumatic features of the vertebral column show strong variation between the left and right side. Condorraptor gen. nov. can be referred to the Tetanurae and is a representative of a global radiation of basal tetanurans in the Early to Mid Jurassic.     

'Vertition' of integumental organs in mites revisited: a case of fluctuating asymmetry.

Vertition in mites is defined as a meristic variation for a bilateral integumental organ with a separate genetic control for each body side. A prominent hypothesis expressed by Grandjean is the role of vertition in the evolutionary trend towards a reduced number of hair-like organs (mechano- and/or chemo-receptors) known to have occurred in many mite groups. Observations on leg setae in the two-spotted spider mite Tetranychus urticae do not support this hypothesis. Meristic variation for leg setae rather conforms to the notion of fluctuating asymmetry: the difference between the number of leg setae on the right and left sides of the body had a unimodal distribution with a mean of zero. Moreover, lack of heritability for left/right absences of leg setae in an inbred laboratory strain suggests that vertition could be purely environmental. It is therefore argued that meristic variation for hair-like organs in mites is caused by random developmental accidents not corrected by homeostatic mechanisms normally resulting in a perfect bilateral symmetry.     

A femoral neck fracture model in rabbits

A technique was developed to create a reproducible femoral neck fracture in vitro using 5-month-old JW/CSK series male rabbits. Force attenuation of a newly developed damping material was also evaluated using this model. Ten pairs of the femora with smaller deviations in length and weight were harvested and cleaned of soft tissue. Either a right or left of each pair of the specimens was randomly selected and put into either the control or the experimental group, both of which contained equal numbers of the right and left femora. The specimens were attached to an L-shaped plate and embedded in a resin from the proximal diaphysis to the distal end so as to maintain a consistent position of the femora. They were mounted and fixed on a pedestal slanted in the coronal plane at 20 degrees. The impact load testing was conducted using an impact mallet dropped from a height of 3 cm. The impact load was applied onto the femoral head. To the specimens in the experimental group, attenuated impact forces were loaded through the damping material, but those in the control group were subjected to forces directly transmitted without the material. All the impact testing was performed in a temperature and humidity controlled chamber. All of the femoral specimens exposed to the direct impact forces (controlled group) sustained fracture at the neck. The fracture line passed from the base of the femoral head laterally and to the calcar area just proximal to the minor trochanter medially. The location of each fracture line was almost identical among the specimens. None of the specimens that were exposed to the impact force through the damping material (experimental group) sustained fracture macroscopically and roentgenographically.     

A study of nasolacrimal canal in crania from Uttar Pradesh (India)

The length of the nasolacrimal canal and the diameter of its superior aperture were measured in 200 adult skulls from Uttar Pradesh (India). The mean length of the right and left canals were 2.15 cm and 2.39 cm, respectively. The antero-posterior diameter of the superior aperture is more than that of the transverse diameter in both the sides. The right canal has got a larger transverse diameter. But its antero-posterior diameter is less than that of the left side. The correlations between the various measurements were calculated. A positive correlation between the canal length and the nose length has been observed.     

新疆准噶尔盆地侏罗纪石树沟组上部一大型兽脚类跖骨

准噶尔盆地中侏罗世晚期到晚侏罗世早期沉积的石树沟组产出过包括多种兽脚类恐龙在内的大量脊椎动物化石。描述了一件新的采自准噶尔盆地东北缘五彩湾地区石树沟组上部的兽脚类恐龙左第四跖骨标本(IVPPV18060)。通过与其他兽脚类恐龙第四跖骨对比,该标本可归入异特龙超科(Allosauroidea)。它与其他异特龙超科第四跖骨的相似性包括:近端关节面三角形并有一向后方延伸的舌状突出,向外侧轻微弯曲的骨干,位于骨干后方靠近外侧边的半月形肌肉凹陷,三角形骨干横截面。在异特龙超科当中,V18060与准噶尔盆地将军庙地区石树沟组中发现的董氏中华盗龙(Sinraptordongi)最为相似(除了以上相似性,V18060和董氏中华盗龙的相似性还包括远端关节轮廓呈近梯形,骨干后部肌肉凹陷与周围边界呈半开放状态)。但是,V18060和董氏中华盗龙也存在着一些明显的区别:V18060明显比董氏中华盗龙的第四跖骨粗壮,远端内外两髁大小差异相反。这些形态差异可能是由于个体发育或者性双形造成的,也可能代表分类学差异。对比研究和基于第四跖骨形态信息进行的分支系统学分析结果更偏向后一种解释:V18060代表一个不同于董氏中华盗龙但与后者亲缘关系很近的新的兽脚类恐龙。新材料的发现增加了中晚侏罗世石树沟动物群兽脚类恐龙的分异度。在五彩湾和将军庙地区发现不同的中华盗龙类恐龙指示了晚侏罗世早期准噶尔盆地中相邻地区可能存在着一定的生态分异性或者地理隔离。     

Impaired muscle glycogen storage after muscle biopsy

To assess the effects of repeated needle biopsies on the rate of muscle glycogen repletion, eight male subjects were studied immediately after and 2 days after an exhaustive cycling bout. A single biopsy was obtained from the right vastus lateralis muscle immediately after an exhaustive cycling bout. Two days later, a sample was taken 1 cm lateral or medial to sample A. In four of these subjects, additional biopsies were taken 3 cm distal and proximal. A control specimen was also taken from the left leg 2 days after the exercise. Ten days after the exercise, muscle was again sampled from each leg of these four subjects. Analysis of these samples revealed that the initial biopsy impaired glycogen storage in the muscle taken 1 cm medial or lateral to the previous site. This reduction in glycogen storage was most pronounced in the first 2 days after the exercise. Samples taken distal and proximal to the initial biopsy contained, on the average, less glycogen than the contralateral leg, but these differences were only significantly different in the distal muscle sample. Alteration in muscle glycogen storage was seen to persist for 10 days after the first biopsy, suggesting that care must be taken in selecting the site for repeated biopsies from the same muscle.