Ontogenetic scaling patterns and functional anatomy of the pelvic limb musculature in emus (Dromaius novaehollandiae)

Emus (Dromaius novaehollandiae) are exclusively terrestrial, bipedal and cursorial ratites with some similar biomechanical characteristics to humans. Their growth rates are impressive as their body mass increases eighty-fold from hatching to adulthood whilst maintaining the same mode of locomotion throughout life. These ontogenetic characteristics stimulate biomechanical questions about the strategies that allow them to cope through these changes. To answer such questions, in this study we have collected pelvic limb anatomical data (muscle architecture, tendon length, tendon mass and bone lengths) and calculated muscle physiological cross sectional area (PCSA) and average tendon cross sectional area from emus across an ontogenetic series (n=17, body masses from 3.6 to 42 kg). The data were analysed by reduced major axis regression to determine scaling relationships with body mass. Muscle mass and PCSA showed a marked trend towards positive allometry (26 and 27 out of 34 muscles respectively) and fascicle length showed a more mixed scaling pattern. The long tendons of the main digital flexors scaled with positive allometry for all characteristics whilst other tendons demonstrated a less clear scaling pattern. Finally, the two longer bones of the limb (tibiotarsus and tarsometatarsus) also exhibited positive allometry for length and the other two (femur and first phalanx of the pes) had trends towards isometry. These results indicate that emus increase their muscle force-generating capacities, as well as potentially increasing the force-sustaining capacities of their tendons, as they grow. Furthermore, we have clarified anatomical descriptions and provided illustrations of the pelvic limb muscle-tendon units in emus.

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Ontogenetic scaling patterns and functional anatomy of the pelvic limb musculature in emus (Dromaius novaehollandiae)

10.7287/peerj.preprints.508v2 ◽

2014 ◽

Author(s):

Luis P Lamas ◽

Russell P Main ◽

John R. Hutchinson

Keyword(s):

Body Mass ◽

Functional Anatomy ◽

Major Axis ◽

Cross Sectional Area ◽

Sectional Area ◽

Fascicle Length ◽

Cross Sectional ◽

Positive Allometry ◽

Dromaius Novaehollandiae ◽

Pelvic Limb

Emus (Dromaius novaehollandiae) are exclusively terrestrial, bipedal and cursorial ratites with some similar biomechanical characteristics to humans. Their growth rates are impressive as their body mass increases eighty-fold from hatching to adulthood whilst maintaining the same mode of locomotion throughout life. These ontogenetic characteristics stimulate biomechanical questions about the strategies that allow emus to cope with their rapid growth and locomotion, which can be partly addressed via scaling (allometric) analysis of morphology. In this study we have collected pelvic limb anatomical data (muscle architecture, tendon length, tendon mass and bone lengths) and calculated muscle physiological cross sectional area (PCSA) and average tendon cross sectional area from emus across three ontogenetic stages (n=17, body masses from 3.6 to 42 kg). The data were analysed by reduced major axis regression to determine how these biomechanically relevant aspects of morphology scaled with body mass. Muscle mass and PCSA showed a marked trend towards positive allometry (26 and 27 out of 34 muscles respectively) and fascicle length showed a more mixed scaling pattern. The long tendons of the main digital flexors scaled with positive allometry for all characteristics whilst other tendons demonstrated a less clear scaling pattern. Finally, the two longer bones of the limb (tibiotarsus and tarsometatarsus) also exhibited positive allometry for length and the two others (femur and first phalanx of digit III) had trends towards isometry. These results indicate that emus experience a relative increase in their muscle force-generating capacities, as well as potentially increasing the force-sustaining capacities of their tendons, as they grow. Furthermore, we have clarified anatomical descriptions and provided illustrations of the pelvic limb muscle-tendon units in emus.

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Ontogenetic scaling patterns and functional anatomy of the pelvic limb musculature in emus (Dromaius novaehollandiae)

10.7287/peerj.preprints.508 ◽

2014 ◽

Cited By ~ 1

Author(s):

Luis P Lamas ◽

Russell P Main ◽

John R. Hutchinson

Keyword(s):

Body Mass ◽

Functional Anatomy ◽

Major Axis ◽

Cross Sectional Area ◽

Sectional Area ◽

Fascicle Length ◽

Cross Sectional ◽

Positive Allometry ◽

Dromaius Novaehollandiae ◽

Pelvic Limb

Emus (Dromaius novaehollandiae) are exclusively terrestrial, bipedal and cursorial ratites with some similar biomechanical characteristics to humans. Their growth rates are impressive as their body mass increases eighty-fold from hatching to adulthood whilst maintaining the same mode of locomotion throughout life. These ontogenetic characteristics stimulate biomechanical questions about the strategies that allow emus to cope with their rapid growth and locomotion, which can be partly addressed via scaling (allometric) analysis of morphology. In this study we have collected pelvic limb anatomical data (muscle architecture, tendon length, tendon mass and bone lengths) and calculated muscle physiological cross sectional area (PCSA) and average tendon cross sectional area from emus across three ontogenetic stages (n=17, body masses from 3.6 to 42 kg). The data were analysed by reduced major axis regression to determine how these biomechanically relevant aspects of morphology scaled with body mass. Muscle mass and PCSA showed a marked trend towards positive allometry (26 and 27 out of 34 muscles respectively) and fascicle length showed a more mixed scaling pattern. The long tendons of the main digital flexors scaled with positive allometry for all characteristics whilst other tendons demonstrated a less clear scaling pattern. Finally, the two longer bones of the limb (tibiotarsus and tarsometatarsus) also exhibited positive allometry for length and the two others (femur and first phalanx of digit III) had trends towards isometry. These results indicate that emus experience a relative increase in their muscle force-generating capacities, as well as potentially increasing the force-sustaining capacities of their tendons, as they grow. Furthermore, we have clarified anatomical descriptions and provided illustrations of the pelvic limb muscle-tendon units in emus.

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Gastrocnemius Medialis Muscle Geometry and Extensibility in Typically Developing Children and Children With Spastic Paresis Aged 6–13 Years

Frontiers in Physiology ◽

10.3389/fphys.2020.528522 ◽

2020 ◽

Vol 11 ◽

Author(s):

Guido Weide ◽

Peter A. Huijing ◽

Lynn Bar-On ◽

Lizeth Sloot ◽

Annemieke I. Buizer ◽

...

Keyword(s):

Body Mass ◽

Lower Leg ◽

Cross Sectional Area ◽

Typically Developing ◽

Sectional Area ◽

Leg Length ◽

Fascicle Length ◽

Cross Sectional ◽

Muscle Geometry ◽

Spastic Paresis

Gait of children with spastic paresis (SP) is frequently characterized by a reduced ankle range of motion, presumably due to reduced extensibility of the triceps surae (TS) muscle. Little is known about how morphological muscle characteristics in SP children are affected. The aim of this study was to compare gastrocnemius medialis (GM) muscle geometry and extensibility in children with SP with those of typically developing (TD) children and assess how GM morphology is related to its extensibility. Thirteen children with SP, of which 10 with a diagnosis of spastic cerebral palsy and three with SP of unknown etiology (mean age 9.7 ± 2.1 years; GMFCS: I–III), and 14 TD children (mean age 9.3 ± 1.7 years) took part in this study. GM geometry was assessed using 3D ultrasound imaging at 0 and 4 Nm externally imposed dorsal flexion ankle moments. GM extensibility was defined as its absolute length change between the externally applied 0 and 4 Nm moments. Anthropometric variables and GM extensibility did not differ between the SP and TD groups. While in both groups, GM muscle volume correlated with body mass, the slope of the regression line in TD was substantially higher than that in SP (TD = 3.3 ml/kg; SP = 1.3 ml/kg, p < 0.01). In TD, GM fascicle length increased with age, lower leg length and body mass, whereas in SP children, fascicle length did not correlate with any of these variables. However, the increase in GM physiological cross-sectional area as a function of body mass did not differ between SP and TD children. Increases in lengths of tendinous structures in children with SP exceeded those observed in TD children (TD = 0.85 cm/cm; SP = 1.16 cm/cm, p < 0.01) and even exceeded lower-leg length increases. In addition, only for children with SP, body mass (r = −0.61), height (r = −0.66), muscle volume (r = − 0.66), physiological cross-sectional area (r = − 0.59), and tendon length (r = −0.68) showed a negative association with GM extensibility. Such negative associations were not found for TD children. In conclusion, physiological cross-sectional area and length of the tendinous structures are positively associated with age and negatively associated with extensibility in children with SP.

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The Jaw Adductor Resultant and Estimated Bite Force in Primates

Anatomy Research International ◽

10.1155/2011/929848 ◽

2011 ◽

Vol 2011 ◽

pp. 1-11 ◽

Cited By ~ 12

Author(s):

Jonathan M. G. Perry ◽

Adam Hartstone-Rose ◽

Rachel L. Logan

Keyword(s):

Temporomandibular Joint ◽

Body Mass ◽

Bite Force ◽

Cross Sectional Area ◽

Primate Species ◽

Sectional Area ◽

Cross Sectional ◽

Joint Distraction ◽

Jaw Adductors

We reconstructed the jaw adductor resultant in 34 primate species using new data on muscle physiological cross-sectional area (PCSA) and data on skull landmarks. Based on predictions by Greaves, the resultant should (1) cross the jaw at 30% of its length, (2) lie directly posterior to the last molar, and (3) incline more anteriorly in primates that need not resist large anteriorly-directed forces. We found that the resultant lies significantly posterior to its predicted location, is significantly posterior to the last molar, and is significantly more anteriorly inclined in folivores than in frugivores. Perhaps primates emphasize avoiding temporomandibular joint distraction and/or wide gapes at the expense of bite force. Our exploration of trends in the data revealed that estimated bite force varies with body mass (but not diet) and is significantly greater in strepsirrhines than in anthropoids. This might be related to greater contribution from the balancing-side jaw adductors in anthropoids.

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Contractile properties of rat, rhesus monkey, and human type I muscle fibers

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1997.272.1.r34 ◽

1997 ◽

Vol 272 (1) ◽

pp. R34-R42 ◽

Cited By ~ 15

Author(s):

J. J. Widrick ◽

J. G. Romatowski ◽

M. Karhanek ◽

R. H. Fitts

Keyword(s):

Rhesus Monkey ◽

Body Mass ◽

Fiber Length ◽

Peak Power ◽

Cross Sectional Area ◽

Contractile Properties ◽

Type I ◽

Sectional Area ◽

Shortening Velocity ◽

Cross Sectional

It is well known that skeletal muscle intrinsic maximal shortening velocity is inversely related to species body mass. However, there is uncertainty regarding the relationship between the contractile properties of muscle fibers obtained from commonly studied laboratory animals and those obtained from humans. In this study we determined the contractile properties of single chemically skinned fibers prepared from rat, rhesus monkey, and human soleus and gastrocnemius muscle samples under identical experimental conditions. All fibers used for analysis expressed type I myosin heavy chain as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Allometric coefficients for type I fibers from each muscle indicated that there was little change in peak tension (force/fiber cross-sectional area) across species. In contrast, both soleus and gastrocnemius type I fiber maximal unloaded shortening velocity (Vo), the y-intercept of the force-velocity relationship (Vmax), peak power per unit fiber length, and peak power normalized for fiber length and cross-sectional area were all inversely related to species body mass. The present allometric coefficients for soleus fiber Vo (-0.18) and Vmax (-0.11) are in good agreement with published values for soleus fibers obtained from common laboratory and domesticated mammals. Taken together, these observations suggest that the Vo of slow fibers from quadrupeds and humans scale similarly and can be described by the same quantitative relationships. These findings have implications in the design and interpretation of experiments, especially those that use small laboratory mammals as a model of human muscle function.

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Persistent functional loss following ruptured Achilles tendon is associated with reduced gastrocnemius muscle fascicle length, elongated gastrocnemius and soleus tendon, and reduced muscle cross‐sectional area

Translational Sports Medicine ◽

10.1002/tsm2.103 ◽

2019 ◽

Vol 2 (6) ◽

pp. 316-324 ◽

Cited By ~ 5

Author(s):

René B. Svensson ◽

Christian Couppé ◽

Anne‐Sofie Agergaard ◽

Christian Ohrhammar Josefsen ◽

Mikkel Holm Jensen ◽

...

Keyword(s):

Achilles Tendon ◽

Gastrocnemius Muscle ◽

Cross Sectional Area ◽

Sectional Area ◽

Fascicle Length ◽

Cross Sectional ◽

Functional Loss ◽

Muscle Fascicle ◽

Muscle Cross Sectional Area

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Effect of aging on human muscle architecture

Journal of Applied Physiology ◽

10.1152/japplphysiol.00433.2003 ◽

2003 ◽

Vol 95 (6) ◽

pp. 2229-2234 ◽

Cited By ~ 279

Author(s):

M. V. Narici ◽

C. N. Maganaris ◽

N. D. Reeves ◽

P. Capodaglio

Keyword(s):

The Elderly ◽

Muscle Architecture ◽

Cross Sectional Area ◽

Elderly Group ◽

Sectional Area ◽

Morphometric Measurements ◽

Fascicle Length ◽

Cross Sectional ◽

Physically Active ◽

Structural Alterations

The effect of aging on human gastrocnemius medialis (GM) muscle architecture was evaluated by comparing morphometric measurements on 14 young (aged 27–42 yr) and on 16 older (aged 70–81 yr) physically active men, matched for height, body mass, and physical activity. GM muscle anatomic cross-sectional area (ACSA) and volume (Vol) were measured by computerized tomography, and GM fascicle length ( Lf) and pennation angle (θ) were assessed by ultrasonography. GM physiological cross-sectional area (PCSA) was calculated as the ratio of Vol/ Lf. In the elderly, ACSA and Vol were, respectively, 19.1% ( P < 0.005) and 25.4% ( P < 0.001) smaller than in the young adults. Also, Lf and θ were found to be smaller in the elderly group by 10.2% ( P < 0.01) and 13.2% ( P < 0.01), respectively. When the data for the young and elderly adults were pooled together, θ significantly correlated with ACSA ( P < 0.05). Because of the reduced Vol and Lf in the elderly group, the resulting PCSA was found to be 15.2% ( P < 0.05) smaller. In conclusion, this study demonstrates that aging significantly affects human skeletal muscle architecture. These structural alterations are expected to have implications for muscle function in old age.

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