Ratio Of Limb Length Research Articles

Finite Element Analysis of Axial Compression Behavior of L-Shaped Concrete-Filled Steel Tubular Columns with Different Combinations

L-shaped concrete-filled steel tubular (CFST) columns, a kind of structural member appropriate for high-rise buildings, not only avoid the defect of conventional square columns protruding from the wall but also have the green and low-carbon properties of steel structures appropriate for fabricated construction. To learn more about their axial compression behavior, refined 3D finite element models were established using the general finite element software ABAQUS. The reliability of the models was subsequently verified based on failure tests and load–displacement relation tests on eight L-shaped specimens. The axial compression mechanism of L-shaped CFST columns was investigated using the verified finite element models. Further systematic parameter analysis was carried out to investigate the influence of parameters such as steel strength, concrete strength, length ratio of long limb to short limb, the angle between the two limbs, and combination methods on the axial compression behavior of L-shaped CFST columns. The results demonstrate that the angle between the two limbs has a significant impact on the stress distribution of concrete and steel pipes. The corner effect increases as the angle between the two limbs decreases. The combination of F-type specimens can better exert the constraint effect of steel pipes on concrete, while the triangular cavity of unequal-limb specimens and specimens with an included angle of 60° cannot effectively trigger the interaction between steel pipes and concrete. The initial stiffness of L-shaped CFST columns increases with an increase in concrete strength and a decrease in limb length ratio, which is not sensitive to changes in steel strength and the included angle. The peak bearing capacity of the specimens increases with increases in steel strength and concrete strength and a decrease in the limb length ratio. Compared to C-type and Z-type specimens, the initial stiffness of F-type specimens is slightly higher, and the peak bearing capacity is significantly increased.

Increased lower limb length ratio in patients with patellar instability

PurposePatellar height is a risk factor for patellar instability, correlated with the tibia length/femur length (T/F) ratio. This study aimed to explore the changes in the T/F ratio in patients with patella instability and the potential correlation with the morphology of the patellofemoral joint and extensor moment arm.MethodA retrospective analysis was performed to assess the ratio of lower limb length morphological characteristics of the patellofemoral by full weight-bearing long-leg standing radiographs, magnetic resonance imaging, and computed tomography in 75 patients with patellar instability and 75 participants from a randomly selected control group from January 2020 to September 2021. A total of eight parts were measured, including mechanical tibia length/femur length (mT/F) ratio, anatomical tibia length/femur length (aT/F) ratio, hip–knee–ankle angle, femoral neck-shaft angle, femoral valgus cut angle, patellar height, Dejour classification, sulcus angle, trochlear angle, medial trochlear inclination, lateral trochlear inclination, patella tilt angle and patellar tendon moment arm to evaluate the difference of morphology between patient group and control groups.ResultsThe mT/F (0.840 ± 0.031 vs. 0.812 ± 0.026, p < 0.001) and aT/F (0.841 ± 0.033 vs. 0.808 ± 0.028, p < 0.001) ratios in the patient group were significantly greater than that in the control group. There was a significant correlation between patellar height and increased mT/F and aT/F ratios (p < 0.05).ConclusionPatients with patellar instability had a larger lower limb length ratio, and the change in lower limb length ratio was correlated with patellar height.Level of evidence IV.

Moment arm function dictates patella sagittal height anatomy: Rabbit epiphysiodesis model alters limb length ratios and subsequent patellofemoral anatomical development.

Patellofemoral anatomical dysplasia is associated with patellofemoral instability and pain. The closure of the knee physis occurs at the same age as the peak incidence of patellofemoral dislocation. This study determined the effect on the patellofemoral anatomical development in a rabbit epiphysiodesis model. Twenty-four skeletally immature New Zealand White rabbits were divided into three groups (a) distal femur epiphysiodesis (FE) (b) proximal tibia epiphysiodesis (TE) (c) control; no epiphysiodesis (C) performed at 6 weeks of age. The primary endpoint was shape analysis using three-dimensional reconstructions of micro-computed tomographys (CTs) performed at 30 weeks of age. The limb length ratios (femur:tibia) were significantly different for both FE (mean 0.72, SD 0.0381, P < .001) and TE (mean 0.91, SD 0.0383, P < .001) treatment groups compared to control (mean 0.81, SD 0.0073). Patella height, as measured from the most distal point of the patella to the tibial joint surface (modified Caton-Deschamps measurement), was lower (baja) in the FE and higher (alta) for the TE, compared with the control group. Our findings suggest femoral and tibial shortening can influence the development of the patellofemoral joint, which may be dictated by moment arm function and is potentially responsible for the etiology of patella alta. Future studies are warranted to explore this association further with the view for the development of treatment options for patella alta in human patients.

Lower-extremity growth patterns and skeletal maturation in children with unilateral fibular hemimelia.

Fibular hemimelia is the most common congenital long-bone deficiency. It is usually unilateral and results in a limb-length discrepancy. The literature generally subscribes to the concept of constant inhibition, a process by which limb-length ratios between the shorter and longer extremity remain constant throughout growth, but scientific data supporting this concept are sparse. Additionally, recent literature suggests that these children have abnormal skeletal maturation. To elucidate the lower-extremity long-bone growth patterns and skeletal maturation of children with unilateral fibular hemimelia. We reviewed medical records of children with unilateral fibular hemimelia seen at a large pediatric hospital over a 17-year period. Inclusion criteria were: at least two scanograms prior to any shortening/lengthening procedure, and no other congenital or acquired disorders. We collected the study cohort's femoral and tibial lengths (scanogram reports), plotted them against patient chronological ages and compared them to published growth standards. When these children's bone ages (Greulich and Pyle) were available, we plotted them against the children's chronological ages. Twenty-three children were included (total=115 scanograms). At least 1 bone-age assessment was performed in 19 children (total=84 bone ages). All bone growth curves were within normal growth standards for the femur and tibia. Length ratios between shorter and longer limbs remained constant. Skeletal maturation was within two standard deviations of normal in 90% of bone ages. Lower-extremity long bones of children with unilateral fibular hemimelia have relatively normal growth curves, supporting and confirming the concept of constant inhibition. Most children show normal skeletal maturation.

Residual network based on convolution attention model and feature fusion for dance motion recognition

Traditional posture recognition methods have the problems of low accuracy. Therefore, we propose a residual network based on convolution attention model and future fusion for dance motion recognition. Firstly, the fusion features of the relative position, angle and limb length ratio of human body ar

Estimating the hemodynamic influence of variable main body-to-iliac limb length ratios in aortic endografts.

We conducted a computational study to assess the hemodynamic impact of variant main body-to-iliac limb length (L1/L2) ratios on certain hemodynamic parameters acting on the endograft (EG) either on the normal bifurcated (Bif) or the cross-limb (Cx) fashion. A customary bifurcated 3D model was computationally created and meshed using the commercially available ANSYS ICEM (Ansys Inc., Canonsburg, PA, USA) software. The total length of the EG, was kept constant, while the L1/L2 ratio ranged from 0.3 to 1.5 in the Bif and Cx reconstructed EG models. The compliance of the graft was modeled using a Fluid Structure Interaction method. Important hemodynamic parameters such as pressure drop along EG, wall shear stress (WSS) and helicity were calculated. The greatest pressure decrease across EG was calculated in the peak systolic phase. With increasing L1/L2 it was found that the Pressure Drop was increasing for the Cx configuration, while decreasing for the Bif. The greatest helicity (4.1 m/s2) was seen in peak systole of Cx with ratio of 1.5 whereas its greatest value (2 m/s2) was met in peak systole in the Bif with the shortest L1/L2 ratio (0.3). Similarly, the maximum WSS value was highest (2.74Pa) in the peak systole for the 1.5 L1/L2 of the Cx configuration, while the maximum WSS value equaled 2 Pa for all length ratios of the Bif modification (with the WSS found for L1/L2=0.3 being marginally higher). There was greater discrepancy in the WSS values for all L1/L2 ratios of the Cx bifurcation compared to Bif. Different L1/L2 rations are shown to have an impact on the pressure distribution along the entire EG while the length ratio predisposing to highest helicity or WSS values is also determined by the iliac limbs pattern of the EG. Since current custom-made EG solutions can reproduce variability in main-body/iliac limbs length ratios, further computational as well as clinical research is warranted to delineate and predict the hemodynamic and clinical effect of variable length ratios.

Invasive cane toads are unique in shape but overlap in ecological niche compared to Australian native frogs.

SummaryInvasive species are an important issue worldwide but predicting invasiveness, and the underlying mechanisms that cause it, is difficult. There are several primary hypotheses to explain invasion success. Two main hypothesis based on niche spaces stand out as alternative, although not exclusive. The empty niche hypothesis states that invaders occupy a vacant niche space in the recipient community, and the niche competition hypothesis states that invaders overlap with native species in niche space. Studies on trait similarity/dissimilarity between the invader and native species can provide information on their niche overlap. Here, we use the highly invasive and well‐studied cane toad (Rhinella marina) to test these two hypotheses in Australia, and assess its degree of overlap with native species in several niche dimensions. We compare extensive morphological and environmental data of this successful invader to 235 species (97%) of native Australian frogs. Our study is the first to document the significant morphological differences between the invasive cane toad and a continent‐wide frog radiation: despite significant environmental overlap, cane toads were distinct in body size and shape from most Australian frog species, suggesting that in addition to their previously documented phenotypic plasticity and wide environmental and trophic niche breadth, their unique shape also may have contributed to their success as an invasive species in Australia. Thus, the invasive success of cane toads in Australia may be explained through them successfully colonizing an empty niche among Australian anurans. Our results support that the cane toad's distinct morphology may have played a unique role in the invasiveness of this species in Australia, which coupled with a broad environmental niche breadth, would have boosted their ability to expand their distribution across Australia. We also propose RLLR (Relative limb length ratio) as a potentially useful measure of identifying morphological niche uniqueness and a potential measure of invasiveness potential in anuran amphibians.

Achondroplasia: Really rhizomelic?

Achondroplasia is the most common form of short limb dwarfism in humans. The shortening of the limb lengths in achondroplasia is widely described as "rhizomelic." While this appearance may be convincing clinically, the description is not necessarily true or helpful radiologically. The aims of this study, were therefore, to determine whether rhizomelic shortening is a true feature of achondroplasia at diagnosis in infancy. Humeral, radial, femoral, and tibial diaphyseal lengths were recorded by two independent observers from 22 skeletal surveys of infants with achondroplasia and compared with 150 normal age-matched control subjects. Upper and lower limb bone length ratios (radial/humeral and tibial/femoral lengths, respectively) in both groups were compared using an unpaired t-test. Mean upper limb length ratios were statistically higher within the achondroplasia group at 0.87 ± 0.04 (n = 22, mean age 70 ± 94 days) compared to normal controls at 0.79 ± 0.02 (n = 150, mean age 113 days ± 88 days; P < 0.0001). Lower limb length ratios were not significantly different between groups (0.84 ± 0.04 vs. 0.83 ± 0.02, P = 0.46). There was good inter-observer agreement of limb length measurements, with an average measurement difference of 0.1 ± 1.4 mm. In conclusion, infants with achondroplasia demonstrate statistically significant rhizomelic shortening within the upper limbs, but not lower limbs at diagnosis, compared to normal controls. The term "rhizomelic shortening" in relation to achondroplasia should be reserved when describing upper limb proportions. © 2016 Wiley Periodicals, Inc.

Hand anthropometry in patients with carpal tunnel syndrome: a case-control study with a matched control group of healthy volunteers.

The aim of this study was to perform anthropometrical measure- ments of patients' hands with carpal tunnel syndrome (CTS) in order to evaluate if there is a correlation between CTS occurrence and hand features regarding sexual dimorphism, age and physical activity. Study sample consisted of 48 patients (33 females) and control group included 80 healthy volunteers (58 females) with no history of CTS. The following measurements were performed: the wrist circumference, length of the hand, the hand's width, width of the wrist, thickness of the wrist, height of the hypothenar and thenar, length of the arm and forearm, circumference of the proximal phalanges and width of the digits; as well as several indexes were calculated i.e.: body mass index (BMI), shape index, digit index, wrist index, hand length/height ratio (HLH-ratio) and hand length/upper limb length ratio (HLULL-ratio). Correlation coincidences were analysed between circumferences within the hand, palm and body weight. All parameters except fingers were correlated with body weight in either gender in both groups (p < 0.05; r = 0.40-0.80); Furthermore, width of the hand was correlated with body height (p < 0.001; r = 0.56-0.71). Mean values of wrist index for CTS patients were: males: 0.8, females: 0.74 (significantly higher than in healthy individuals and indicating square shape); shape index: males 76.5, females 75.8; digit index: males 55.7, females 56.5. The calculated HLH-ratio in CTS group was: males 10.6, females 10.9; HLULL-ratio: males 23.6, females 24.9 and they did not differ significantly from healthy volunteers. Almost 90.0% of females with diagnosed CTS have BMI > 25.0 kg/m2. There are significant differences in morphometrical features of the upper limbs between CTS patients and healthy individuals. Hands of patients with CTS are more massive and with 'plumb' fingers and square shape of the wrist. Furthermore, higher BMI values were confirmed to be predisposing factors in CTS occurrence.

Optimal Body Size and Limb Length Ratios Associated with 100-m Personal-Best Swim Speeds.

This study aims to identify optimal body size and limb segment length ratios associated with 100-m personal-best (PB) swim speeds in children and adolescents. Fifty national-standard youth swimmers (21 males and 29 females age 11-16 yr; mean ± SD age, 13.5 ± 1.5 yr) participated in the study. Anthropometry comprised stature; body mass; skinfolds; maturity offset; upper arm, lower arm, and hand lengths; and upper leg, lower leg, and foot lengths. Swimming performance was taken as the PB time recorded in competition for the 100-m freestyle swim. To identify the optimal body size and body composition components associated with 100-m PB swim speeds (having controlled for age and maturity offset), we adopted a multiplicative allometric log-linear regression model, which was refined using backward elimination. Lean body mass was the singularly most important whole-body characteristic. Stature and body mass did not contribute to the model, suggesting that the advantage of longer levers was limb-specific rather than a general whole-body advantage. The allometric model also identified that having greater limb segment length ratios [i.e., arm ratio = (low arm)/(upper arm); foot-to-leg ratio = (foot)/(lower leg)] was key to PB swim speeds. It is only by adopting multiplicative allometric models that the above mentioned ratios could have been derived. The advantage of having a greater lower arm is clear; however, having a shorter upper arm (achieved by adopting a closer elbow angle technique or by possessing a naturally endowed shorter upper arm), at the same time, is a new insight into swimming performance. A greater foot-to-lower-leg ratio suggests that a combination of larger feet and shorter lower leg length may also benefit PB swim speeds.

Sensitivity Parameter Analysis of Bearing Capacity and Ductility of Reinforced Concrete Columns with Z-Shaped Cross-Section

In order to select sensitivity parameter of bearing capacity and ductility, the orthogonal design method was used to research reinforced concrete (RC) columns with Z-shaped cross-section under compression and bending, by the nonlinear analysis computer program of RC columns with irregularly-shaped cross-section. The seven parameters and four levels of orthogonal design were researched, for example ratio of limb length to limb thickness, ratio of axial compression, loading angle, concrete strength, long reinforce ratio, stirrup diameter and stirrup spacing. The results indicated that the best sensitivity factor of bearing capacity was ratio of limb length to limb thickness, next were loading angle and long reinforce ratio; the best sensitivity factor of ductility was ratio of axial compression, next were stirrup diameter and stirrup spacing. These would afford references for the design of RC columns with Z-shaped cross-section.

Transfemoral Amputations: The Effect of Residual Limb Length and Orientation on Gait Analysis Outcome Measures

The level of function achieved following a transfemoral amputation is believed to be affected by surgical attachment of the remaining musculature, resulting orientation of the femur, residual limb length, and eventual prosthetic fit. Twenty-six subjects underwent gait analysis testing in the current preferred prosthesis more than twenty-four months postamputation. The femoral length and orientation angles of each subject were measured from standing postoperative radiographic scanograms. The subjects were separated into groups for analysis on the basis of the femoral shaft angles and the residual limb length ratios. Gait analysis was performed to collect kinematic and temporospatial parameters. A good correlation was observed between residual femoral length and trunk with regard to forward lean (r = -0.683) and lateral flexion (r = -0.628). A good correlation was also observed between residual femoral length and pelvic motion with regard to pelvic tilt (r = -0.691) and obliquity (r = -0.398). A moderate correlation was observed with speed (r = 0.550), indicating that subjects with shorter residual limbs experienced a greater excursion in the torso and pelvis, while walking at a slower self-selected pace. A significant correlation (r = 0.721, p < 0.001) was observed between the femoral shaft abduction angle and the residual femoral length; the shorter the residual limb, the more abducted it was. The length of the residual femur substantially influences temporospatial and kinematic gait outcomes following transfemoral amputation, and appears to be more important than femoral orientation with regard to these parameters.

F wave to height or limb length ratios as rational alternatives for F wave latency in clinical electrodiagnostic medicine

Objective To delineate the F wave latency/height (Fmin/He) or F wave latency/limb length (Fmin/L) ratio as a more useful alternative for the currently reported shortest latency in milliseconds. Methods One hundred and sixty-six healthy volunteers, 85 upper limbs and 84 lower limbs entered the study. Minimum F wave latencies were determined in median, ulnar, tibial and peroneal nerves. The Fmin/He and Fmin/L ratios of each nerve were calculated. Results F latencies of all nerves had significant correlation with height and limb length but there was no correlation between either Fmin/He or Fmin/L and height in any nerve except for peroneal Fmin/He ( p = 0.04, r = 0.23). Conclusions Using the Fmin/He or Fmin/L ratios are more accurate than reporting only the F wave minimum latency, since these ratios incorporate corrections for height and/or limb length. This method also eliminates the false positive and negative reports caused by using a single reference table for all heights. Significance A unique reference table can be produced using the Fmin/He or Fmin/L for all populations and races, so that the comparison between different population samples can be done easily. Also data of different investigations can be pooled together for meta-analysis purposes when a single reference table is used for different samples.

The Elastic-Plasticity Analysis on Cross-Section Short-Limb Shear Wall

The elastic-plasticity of ten cross-section reinforced-concrete short-limb shear wall specimens under monotonic load are analyzed by ANSYS, which compares the change of load capacity, stiffness and ductility of the shear wall when concrete strength grade and limb-length ratio change. The analysis results show that when concrete strength grade is C30, shear wall of this shape can be made with better performances in load capacity and deformation capacity, and when limb-length ratio is 0.6, the ductility and the ability of the energy dissipation of shear wall is not good, which provides a significant basis for practical engineering section design.

Optimal Limb Length Ratio of Quadruped Robot Minimising Joint Torque on Slopes

This paper aims to determine an optimal structure for a quadruped robot, which will allow the robot’s joint torque sum to be minimised. An animal’s characteristic limb length ratio is a vital part of its overall morphology and the one that enables it to travel easily through its environment. For the same reason, a robot’s structure needs to be suitably designed for locomotion in its working environment. Joint torques are necessary to maintain the posture of the robot and to accelerate joint angles during walking motion, hence, minimisation of joint torques reduces energy consumption. We performed a numerical simulation in which we analysed the joint torques for various limb lengths and slope angles in order to determine the optimal structure of a robot walking on a slope. Our investigation determines that the optimal Ratio of Rear Leg Length (RRL) can be derived by the use of a simulation designed to determine the physical structure of quadruped robot. Our analysis suggests that joint torque will increase as the slope angle becomes steeper if the rear legs of the robot are shorter than its forelegs, and that joint torque will decrease as the slope angle declines if the robot’s forelegs are shorter than its rear legs. Finally, experimental results validated our simulation analysis.

Optimal limb length ratio of quadruped robot minimising joint torque on slopes

This paper aims to determine an optimal structure for a quadruped robot, which will allow the robot's joint torque sum to be minimised. An animal's characteristic limb length ratio is a vital part of its overall morphology and the one that enables it

Preliminary study on kinematic gait analysis in mammals.

The gait of several extant mammals was analyzed so as to provide basic data for the restoration of the terrestrial locomotion of extinct animals. An attempt has been made to establish the correlation between the gaits and the morphological data, as the latter can be obtained even from fossils. Animals walking naturally were recorded on videotape, appropriate frames were then printed for analysis. Five kinds of gaits are illustrated here with supporting graphs. In addition, some diagrams were drawn using variables of the gait cycle, the rhythm of limb work, the rhythm of locomotion and the hindlimb length ratio to the trunk. Changes in the four joint angles during a gait cycle were measured and graphed for comparison with each limb joint among mammals with four typical foot postures. The kind of gait was determined in relation to the limb length ratio, the gait cycle and the position of the center of gravity. The joint angle of limbs is in relation to foot posture. The wrist joint in walking is analogous to the knee joint in the degree, direction and timing of flexion.