scholarly journals Forelimb muscle and joint actions in Archosauria: insights from Crocodylus johnstoni (Pseudosuchia) and Mussaurus patagonicus (Sauropodomorpha)

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3976 ◽  
Author(s):  
Alejandro Otero ◽  
Vivian Allen ◽  
Diego Pol ◽  
John R. Hutchinson
Keyword(s):  
Glenohumeral Joint ◽  
Three Dimensional ◽  
Neutral Position ◽  
Moment Arms ◽  
Crocodylus Johnstoni ◽  
Musculoskeletal Anatomy ◽  
Evolutionary Context ◽  
The Moment ◽  
And Function ◽  
Muscle Actions

Many of the major locomotor transitions during the evolution of Archosauria, the lineage including crocodiles and birds as well as extinct Dinosauria, were shifts from quadrupedalism to bipedalism (and vice versa). Those occurred within a continuum between more sprawling and erect modes of locomotion and involved drastic changes of limb anatomy and function in several lineages, including sauropodomorph dinosaurs. We present biomechanical computer models of two locomotor extremes within Archosauria in an analysis of joint ranges of motion and the moment arms of the major forelimb muscles in order to quantify biomechanical differences between more sprawling, pseudosuchian (represented the crocodile Crocodylus johnstoni) and more erect, dinosaurian (represented by the sauropodomorph Mussaurus patagonicus) modes of forelimb function. We compare these two locomotor extremes in terms of the reconstructed musculoskeletal anatomy, ranges of motion of the forelimb joints and the moment arm patterns of muscles across those ranges of joint motion. We reconstructed the three-dimensional paths of 30 muscles acting around the shoulder, elbow and wrist joints. We explicitly evaluate how forelimb joint mobility and muscle actions may have changed with postural and anatomical alterations from basal archosaurs to early sauropodomorphs. We thus evaluate in which ways forelimb posture was correlated with muscle leverage, and how such differences fit into a broader evolutionary context (i.e. transition from sprawling quadrupedalism to erect bipedalism and then shifting to graviportal quadrupedalism). Our analysis reveals major differences of muscle actions between the more sprawling and erect models at the shoulder joint. These differences are related not only to the articular surfaces but also to the orientation of the scapula, in which extension/flexion movements in Crocodylus (e.g. protraction of the humerus) correspond to elevation/depression in Mussaurus. Muscle action is highly influenced by limb posture, more so than morphology. Habitual quadrupedalism in Mussaurus is not supported by our analysis of joint range of motion, which indicates that glenohumeral protraction was severely restricted. Additionally, some active pronation of the manus may have been possible in Mussaurus, allowing semi-pronation by a rearranging of the whole antebrachium (not the radius against the ulna, as previously thought) via long-axis rotation at the elbow joint. However, the muscles acting around this joint to actively pronate it may have been too weak to drive or maintain such orientations as opposed to a neutral position in between pronation and supination. Regardless, the origin of quadrupedalism in Sauropoda is not only linked to manus pronation but also to multiple shifts of forelimb morphology, allowing greater flexion movements of the glenohumeral joint and a more columnar forelimb posture.

scholarly journals The evolution of pelvic limb muscle moment arms in bird-line archosaurs

2021 ◽  
Vol 7 (12) ◽  
pp. eabe2778
Author(s):  
V. R. Allen ◽  
B. M. Kilbourne ◽  
J. R. Hutchinson
Keyword(s):  
Three Dimensional ◽  
Knee Extensors ◽  
Form And Function ◽  
Moment Arms ◽  
Theropod Dinosaurs ◽  
Musculoskeletal Models ◽  
Hip Abductor ◽  
Pelvic Limb ◽  
The Moment ◽  
And Function

Bipedal locomotion evolved along the archosaurian lineage to birds, shifting from “hip-based” to “knee-based” mechanisms. However, the roles of individual muscles in these changes and their evolutionary timings remain obscure. Using 13 three-dimensional musculoskeletal models of the hindlimbs of bird-line archosaurs, we quantify how the moment arms (i.e., leverages) of 35 locomotor muscles evolved. Our results support two hypotheses: From early theropod dinosaurs to birds, knee flexors’ moment arms decreased relative to knee extensors’, and medial long-axis rotator moment arms for the hip increased (trading off with decreased hip abductor moment arms). Our results reveal how, from the Triassic Period, bipedal theropod dinosaurs gradually modified their hindlimb form and function, shifting more from hip-based to knee-based locomotion and hip-abductor to hip-rotator balancing mechanisms inherited by birds. Yet, we also discover unexpected ancestral specializations in larger Jurassic theropods, lost later in the bird-line, complicating the paradigm of gradual transformation.

scholarly journals Musculoskeletal modeling of an ostrich (Struthio camelus) pelvic limb: Influence of limb orientation on muscular capacity during locomotion

2014 ◽  
Author(s):  
John R Hutchinson ◽  
Jeffery W Rankin ◽  
Jonas Rubenson ◽  
Kate H Rosenbluth ◽  
Robert A Siston ◽  
...  
Keyword(s):  
Muscle Function ◽  
Sagittal Plane ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Limb Muscle ◽  
Struthio Camelus ◽  
Moment Arms ◽  
Extensor Muscles ◽  
Pelvic Limb ◽  
The Moment

We developed a three-dimensional, biomechanical computer model of the 36 major pelvic limb muscle groups in an ostrich (Struthio camelus) to investigate muscle function in this, the largest of extant birds and model organism for many studies of locomotor mechanics, body size, anatomy and evolution. Combined with experimental data, we use this model to test two main hypotheses. We first query whether ostriches use limb orientations (joint angles) that optimize the moment-generating capacities of their muscles during walking or running. Next, we test whether ostriches use limb orientations at mid-stance that keep their extensor muscles near maximal, and flexor muscles near minimal, moment arms. Our two hypotheses relate to the control priorities that a large bipedal animal might evolve under biomechanical constraints to achieve more effective static weight support. We find that ostriches do not use limb orientations to optimize the moment-generating capacities or moment arms of their muscles. We infer that dynamic properties of muscles or tendons might be better candidates for locomotor optimization. Regardless, general principles explaining why species choose particular joint orientations during locomotion are lacking, raising the question of whether such general principles exist or if clades evolve different patterns (e.g. weighting of muscle force-length or force-velocity properties in selecting postures). This leaves theoretical studies of muscle moment arms estimated for extinct animals at an impasse until studies of extant taxa answer these questions. Finally, we compare our model’s results against those of two prior studies of ostrich limb muscle moment arms, finding general agreement for many muscles. Some flexor and extensor muscles exhibit self-stabilization patterns (posture-dependent switches between flexor/extensor action) that ostriches may use to coordinate their locomotion. However, some conspicuous areas of disagreement in our results illustrate some cautionary principles. Importantly, tendon-travel empirical measurements of muscle moment arms must be carefully designed to preserve 3D muscle geometry lest their accuracy suffer relative to that of anatomically realistic models. The dearth of accurate experimental measurements of 3D moment arms of muscles in birds leaves uncertainty regarding the relative accuracy of different modelling or experimental datasets such as in ostriches. Our model, however, provides a comprehensive set of 3D estimates of muscle actions in ostriches for the first time, emphasizing that avian limb mechanics are highly three-dimensional and complex, and how no muscles act purely in the sagittal plane. A comparative synthesis of experiments and models such as ours could provide powerful synthesis into how anatomy, mechanics and control interact during locomotion and how these interactions evolve. Such a framework could remove obstacles impeding the analysis of muscle function in extinct taxa.

scholarly journals Three-dimensional Alignment of the Upper Extremity in the Standing Neutral Position in Healthy Subjects

2022 ◽  
Author(s):  
Yuki Yoshida ◽  
Noboru Matsumura ◽  
Yoshitake Yamada ◽  
Satoshi Hiraga ◽  
Kazunori Ishii ◽  
...  
Keyword(s):  
Upper Extremity ◽  
Internal Rotation ◽  
Glenohumeral Joint ◽  
Three Dimensional ◽  
Upper Extremities ◽  
Neutral Position ◽  
Functional Evaluation ◽  
Ct Scanner ◽  
Angular Rotation ◽  
The Mean

Abstract Background: Though alignment of the spine and lower extremities in the standing neutral position has been evaluated, a few studies evaluating the alignment of the upper extremities have also been made. This study assessed the normal alignment of the upper extremities in the standing neutral position and clarified the three-dimensional angular rotations of the upper extremity joints.Methods: Computed tomography (CT) images of 158 upper extremities from 79 healthy volunteers were prospectively acquired in the standing neutral position using an upright CT scanner. Three-dimensional coordinate systems of the thorax, scapula, humerus, and forearm were designated, and three-dimensional angular rotations of the scapulothoracic, glenohumeral, and elbow joints were calculated.Results: The mean angle of the scapulothoracic joint was 8.5° ± 5.9° of upward rotation, 28.7° ± 5.9° of internal rotation, and 7.9° ± 5.2° of anterior inclination. The mean angle of the glenohumeral joint was 4.4° ± 5.9° of abduction, 9.4° ± 12.3° of internal rotation, and 0.3° ± 4.4° of extension. The mean angle of the elbow joint was 9.6° ± 3.7° of valgus, 88.8° ± 14.3° of pronation, and 15.4° ± 4.2° of flexion. Correlations in angular rotation values were found, and interactions for keeping the upper extremities in a neutral position were observed.Conclusions: This study clarified the three-dimensional angular rotation of upper extremity joints in the standing neutral position using an upright CT scanner. Our results may provide important insights for the functional evaluation of upper extremity alignment.

A Muscle/Ligament Model to Predict Loads on L5/S1 during Three Dimensional Lifting

1997 ◽  
Vol 41 (1) ◽  
pp. 680-684
Author(s):  
Bryan Kirking
Keyword(s):  
Lumbar Spine ◽  
Three Dimensional ◽  
Trunk Muscles ◽  
Average Error ◽  
Moment Arms ◽  
Trunk Musculature ◽  
Using Data ◽  
The Moment ◽  
Spinal Load ◽  
Ligament Model

A muscle / ligament model was constructed to estimate the spinal load that resulted from both muscle and ligament sources during dynamic, three dimensional lifting tasks. The model was tested using data from ten subjects performing lifts over a range of realistic industrial conditions (velocity: 10, 20, or 30 degrees / second; asymmetry: 0, 15, or 30 degrees; and weight lifted: 13.6 or 22.7 Kg). During the task, three dimensional trunk position, trunk velocity, the reaction forces, the reaction moments, and the electromyography of the major trunk musculature were collected. Ligaments were represented in the model as vectors spanning the lumbar spine, with their stress—strain properties taken from the literature. The muscle components were modeled based on the OSU Biodynamic EMG assisted model but excluded any effect not resulting solely from active force generation. Thus, the trunk muscles were also represented by vectors spanning the lumbar spine. For each subject, the model was calibrated for both muscle and ligament moment generation by comparing the predicted moment to the measured applied moment in regions where the appropriate moment component has been shown to dominate. The muscle / ligament model was found to predict the moment at L5/S1 at least as accurately as the muscle—only model (the previously reported OSU Biodynamic EMG assisted model which indirectly combines ligament effects into the muscle effects). Both models predicted moment with an average R square value of 0.8, and average error of 23 N m (p > 0.05). For symmetric upright postures, there was no influence of ligaments so both models predicted similar compression of about 1675 N m. As asymmetry or flexion angle increased, the muscle / ligament model predicted higher compression as a result of the smaller moment arms of the ligaments. In the most extreme posture (40 degrees flexion with 30 degrees asymmetry), the predicted compression from the muscle / ligament model (4250 N) was significantly larger than the muscle—only model (3680N). Finally, all asymmetric conditions resulted in predictions from the muscle / ligament model that exceeded the NIOSH 3400 N tolerance, but only the most asymmetric condition resulted in predictions from the muscle—only model that exceeded the NIOSH limit. Thus, muscle models that do not account for ligament effects may be ineffective in accurately evaluating compression during certain job tasks.

The Effect of Subtalar Arthrodesis Alignment on Ankle Biomechanics

2012 ◽  
Author(s):  
James R. Jastifer ◽  
Peter A. Gustafson ◽  
Robert R. Gorman
Keyword(s):  
Lower Extremity ◽  
Range Of Motion ◽  
Ankle Joint ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Neutral Position ◽  
Moment Arms ◽  
Subtalar Arthrodesis ◽  
Force Moment ◽  
Ankle Biomechanics

Background: The position, axis, and control of each lower extremity joint intimately affects adjacent joint function as well as whole limb performance. There is little describing the biomechanics of subtalar arthrodesis and none describing the effect that subtalar arthrodesis position has on ankle biomechanics. The purpose of the current study is to establish this effect on sagittal plane ankle biomechanics. Methods: A study was performed utilizing a three-dimensional, validated, computational model of the lower extremity. A subtalar arthrodesis was simulated from 20 degrees of varus to 20 degrees of valgus. For each of these subtalar arthrodesis positions, the ankle dorsiflexor and plantarflexor muscles’ fiber force, moment arm, and moments were calculated throughout a physiologic range of motion. Results: Throughout ankle range of motion, plantarflexion and dorsiflexion strength varies with subtalar arthrodesis position. When the ankle joint is in neutral position, plantarflexion strength is maximized in 10 degrees of subtalar valgus and strength varies by a maximum of 2.6% from the peak 221 Nm. In a similar manner, with the ankle joint in neutral position, dorsiflexion strength is maximized with a subtalar joint arthrodesis in 5 degrees of valgus and strength varies by a maximum of 7.5% from the peak 46.8 Nm. The change in strength is due to affected muscle fiber force generating capacities and muscle moment arms. Conclusion: The clinical significance of this study is that subtalar arthrodesis in a position of 5–10 degrees subtalar valgus has biomechanical advantage. This supports previous clinical outcome studies and offers biomechanical rationale for their generally favorable outcomes.

Functional morphology of proximal hindlimb muscles in the frog Rana pipiens

2002 ◽  
Vol 205 (14) ◽  
pp. 1987-2004 ◽  
Author(s):  
William J. Kargo ◽  
Lawrence C. Rome
Keyword(s):  
Rana Pipiens ◽  
Three Dimensional ◽  
Realistic Model ◽  
Moment Arms ◽  
Passive Behavior ◽  
Hindlimb Muscles ◽  
Musculoskeletal Models ◽  
Hindlimb Muscle ◽  
The Moment

SUMMARY Musculoskeletal models have become important tools in understanding motor control issues ranging from how muscles power movement to how sensory feedback supports movements. In the present study, we developed the initial musculotendon subsystem of a realistic model of the frog Rana pipiens. We measured the anatomical properties of 13 proximal muscles in the frog hindlimb and incorporated these measurements into a set of musculotendon actuators. We examined whether the interaction between this musculotendon subsystem and a previously developed skeleton/joint subsystem captured the passive behavior of the real frog's musculoskeletal system. To do this, we compared the moment arms of musculotendon complexes measured experimentally with moment arms predicted by the model. We also compared sarcomere lengths measured experimentally at the starting and take-off positions of a jump with sarcomere lengths predicted by the model at these same limb positions. On the basis of the good fit of the experimental data, we used the model to describe the multi-joint mechanical effects produced by contraction of each hindlimb muscle and to predict muscle trajectories during a range of limb behaviors (wiping, defensive kicking, swimming and jumping). Through these analyses, we show that all hindlimb muscles have multiple functions with respect to accelerating the limb in its three-dimensional workspace and that the balance of functions depends greatly on limb configuration. In addition, we show that muscles have multiple, task-specific functions with respect to the type of contraction performed. The results of this study provide important data regarding the multifunctional role of hindlimb muscles in the frog and form a foundation upon which additional model subsystems (e.g. neural) and more sophisticated muscle models can be appended.

scholarly journals The Spinebot—A Robotic Device to Intraoperatively Quantify Spinal Stiffness

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Philippe Büchler ◽  
Jonas Räber ◽  
Benjamin Voumard ◽  
Steve Berger ◽  
Brett Bell ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Three Dimensional ◽  
Axial Rotation ◽  
Flexion Extension ◽  
Torque Load ◽  
The Moment ◽  
Reference Measurements ◽  
Spine Function ◽  
And Function

Abstract Degenerative spine problems and spinal deformities have high socio-economic impacts. Current surgical treatment is based on bony fusion that can reduce mobility and function. Precise descriptions of the biomechanics of normal, deformed, and degenerated spinal segments under in vivo conditions are needed to develop new approaches that preserve spine function. This study developed a system that intraoperatively measures the three-dimensional segmental stiffness of patient's spine. SpineBot, a parallel kinematic robot, was developed to transmit loads to adjacent vertebrae. A force/torque load cell mounted on the SpineBot measured the moment applied to the spinal segment and calculated segmental stiffnesses. The accuracy of SpineBot was characterized ex vivo by comparing its stiffness measurement of five ovine specimens to measurements obtained with a reference spinal testing system. The SpineBot can apply torques up to 10 N·m along all anatomical axes with a total range of motion of about 11.5 deg ± 0.5 deg in lateral bending, 4.5 deg ± 0.3 deg in flexion/extension, and 2.6 deg ± 0.5 deg in axial rotation. SpineBot's measurements are noisier than the reference system, but the correlation between SpineBot and reference measurements was high (R2 > 0.8). In conclusion, SpineBot's accuracy is comparable to that of current reference systems but can take intraoperative measurements. SpineBot can improve our understanding of spinal biomechanics in patients who have the pathology of interest, and take these measurements in the natural physiological environment, giving us information essential to developing new “nonfusion” products.

scholarly journals Musculoskeletal modeling of an ostrich (Struthio camelus) pelvic limb: Influence of limb orientation on muscular capacity during locomotion

2014 ◽  
Author(s):  
John R Hutchinson ◽  
Jeffery W Rankin ◽  
Jonas Rubenson ◽  
Kate H Rosenbluth ◽  
Robert A Siston ◽  
...  
Keyword(s):  
Muscle Function ◽  
Sagittal Plane ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Limb Muscle ◽  
Struthio Camelus ◽  
Moment Arms ◽  
Extensor Muscles ◽  
Pelvic Limb ◽  
The Moment

We developed a three-dimensional, biomechanical computer model of the 36 major pelvic limb muscle groups in an ostrich (Struthio camelus) to investigate muscle function in this, the largest of extant birds and model organism for many studies of locomotor mechanics, body size, anatomy and evolution. Combined with experimental data, we use this model to test two main hypotheses. We first query whether ostriches use limb orientations (joint angles) that optimize the moment-generating capacities of their muscles during walking or running. Next, we test whether ostriches use limb orientations at mid-stance that keep their extensor muscles near maximal, and flexor muscles near minimal, moment arms. Our two hypotheses relate to the control priorities that a large bipedal animal might evolve under biomechanical constraints to achieve more effective static weight support. We find that ostriches do not use limb orientations to optimize the moment-generating capacities or moment arms of their muscles. We infer that dynamic properties of muscles or tendons might be better candidates for locomotor optimization. Regardless, general principles explaining why species choose particular joint orientations during locomotion are lacking, raising the question of whether such general principles exist or if clades evolve different patterns (e.g. weighting of muscle force-length or force-velocity properties in selecting postures). This leaves theoretical studies of muscle moment arms estimated for extinct animals at an impasse until studies of extant taxa answer these questions. Finally, we compare our model’s results against those of two prior studies of ostrich limb muscle moment arms, finding general agreement for many muscles. Some flexor and extensor muscles exhibit self-stabilization patterns (posture-dependent switches between flexor/extensor action) that ostriches may use to coordinate their locomotion. However, some conspicuous areas of disagreement in our results illustrate some cautionary principles. Importantly, tendon-travel empirical measurements of muscle moment arms must be carefully designed to preserve 3D muscle geometry lest their accuracy suffer relative to that of anatomically realistic models. The dearth of accurate experimental measurements of 3D moment arms of muscles in birds leaves uncertainty regarding the relative accuracy of different modelling or experimental datasets such as in ostriches. Our model, however, provides a comprehensive set of 3D estimates of muscle actions in ostriches for the first time, emphasizing that avian limb mechanics are highly three-dimensional and complex, and how no muscles act purely in the sagittal plane. A comparative synthesis of experiments and models such as ours could provide powerful synthesis into how anatomy, mechanics and control interact during locomotion and how these interactions evolve. Such a framework could remove obstacles impeding the analysis of muscle function in extinct taxa.

Subtalar Pronation — Relationship to the Medial Longitudinal Arch Loading in the Normal Foot

2000 ◽  
Vol 21 (3) ◽  
pp. 216-220 ◽  
Author(s):  
George A. Arangio ◽  
Douglas C. Phillippy ◽  
Dayan Xiao ◽  
Wei-Kai Gu ◽  
Eric P. Salathe
Keyword(s):  
Subtalar Joint ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Biomechanical Model ◽  
Neutral Position ◽  
Medial Longitudinal Arch ◽  
Talonavicular Joint ◽  
First Metatarsal ◽  
Medial Cuneiform ◽  
The Moment

A three-dimensional biomechanical model was used to calculate the mechanical response of the foot to a load of 683 Newtons with the subtalar joint in the neutral position, at five degrees of pronation, and at five degrees of supination. Pronation causes the forefoot to evert, increasing the load borne by the first metatarsal. This results in a 47% increase in the moment about the talonavicular joint and a 58% increase in the moment about the navicular-medial cuneiform joint. Subtalar joint supination causes the forefoot to invert and results in a 55% increase in the moment about the calcaneal-cuboid joint.

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