scholarly journals The Jaw Adductor Resultant and Estimated Bite Force in Primates

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
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.

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

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.

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

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.

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

1997 ◽  
Vol 272 (1) ◽  
pp. R34-R42 ◽  
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.

158. Median nerve cross-sectional area in adults per body mass index

2012 ◽  
Vol 123 (6) ◽  
pp. e62
Author(s):  
C. Gutierrez ◽  
R.N. Sembrano ◽  
A. Ivanescu ◽  
M. Carrion-Jones ◽  
D. Moore
Keyword(s):  
Body Mass Index ◽  
Median Nerve ◽  
Body Mass ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional

scholarly journals Peripheral veins: influence of gender, body mass index, age and varicose veins on cross-sectional area

2003 ◽  
Vol 8 (4) ◽  
pp. 249-255 ◽  
Author(s):  
K Kröger ◽  
C Ose ◽  
G Rudofsky ◽  
J Roesener ◽  
D Weiland ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Varicose Veins ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional

scholarly journals Caecilian jaw-closing mechanics: integrating two muscle systems

2008 ◽  
Vol 5 (29) ◽  
pp. 1491-1504 ◽  
Author(s):  
Thomas Kleinteich ◽  
Alexander Haas ◽  
Adam P Summers
Keyword(s):  
Bite Force ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Lever Arm ◽  
Mandibular Joint ◽  
Wide Range ◽  
Jaw Joint ◽  
Muscle Groups ◽  
Using Data

Caecilians (Lissamphibia: Gymnophiona) are unique among vertebrates in having two sets of jaw-closing muscles, one on either side of the jaw joint. Using data from high-resolution X-ray radiation computed tomography scans, we modelled the effect of these two muscle groups ( mm. levatores mandibulae and m. interhyoideus posterior ) on bite force over a range of gape angles, employing a simplified lever arm mechanism that takes into account muscle cross-sectional area and fibre angle. Measurements of lever arm lengths, muscle fibre orientations and physiological cross-sectional area of cranial muscles were available from three caecilian species: Ichthyophis cf. kohtaoensis ; Siphonops annulatus ; and Typhlonectes natans . The maximal gape of caecilians is restricted by a critical gape angle above which the mm. levatores mandibulae will open the jaw and destabilize the mandibular joint. The presence of destabilizing forces in the caecilian jaw mechanism may be compensated for by a mandibular joint in that the fossa is wrapped around the condyle to resist dislocation. The caecilian skull is streptostylic; the quadrate–squamosal complex moves with respect to the rest of the skull. This increases the leverage of the jaw-closing muscles. We also demonstrate that the unusual jaw joint requires streptostyly because there is a dorsolateral movement of the quadrate–squamosal complex when the jaw closes. The combination of the two jaw-closing systems results in high bite forces over a wide range of gape angles, an important advantage for generalist feeders such as caecilians. The relative sizes and leverage mechanics of the two closing systems allow one to exert more force when the other has a poor mechanical advantage. This effect is seen in all three species we examined. In the aquatic T. natans , with its less well-roofed skull, there is a larger contribution of the mm. levatores mandibulae to total bite force than in the terrestrial I . cf. kohtaoensis and S. annulatus .

scholarly journals THICKNESS AND CROSS-SECTIONAL AREA OF THE ACHILLES TENDON IN MARATHON RUNNERS: A CROSS-SECTIONAL STUDY

2020 ◽  
Vol 26 (5) ◽  
pp. 391-395
Author(s):  
Juan José Salinero ◽  
Beatriz Lara ◽  
Jorge Gutierrez-Hellin ◽  
César Gallo-Salazar ◽  
Francisco Areces ◽  
...  
Keyword(s):  
Achilles Tendon ◽  
Range Of Motion ◽  
Ankle Joint ◽  
Body Mass ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Marathon Runners ◽  
Tendon Thickness

ABSTRACT Introduction: This study aimed to measure thickness and cross-sectional area of the Achilles tendon (AT), and the range of motion of the ankle joint in dorsiflexion of amateur marathon runners compared to non-active people. Objectives: To analyze the relationship between cross-sectional area and thickness of the Achilles tendon in marathon runners and age, anthropometric characteristics (height and body mass), training habits, running experience, marathon performance, and range of motion in the ankle joint. Methods: Achilles tendon thickness and cross-sectional area were measured using ultrasound images of the left leg in 97 male amateur marathon runners (age 42.0 ± 9.6 years; height 175 ± 6 cm; and body mass 73.7 ± 8.6 kg), and 47 controls (39.9 ± 11.6 years; 176 ± 7 cm; 79.6 ± 16.1 kg). Results: Achilles tendon thickness (4.81 ± 0.77 vs. 4.60 ± 0.66 mm; p = 0.01) and cross-sectional area (60.41 ± 14.36 vs. 53.62 ± 9.90 mm2; p < 0.01) were greater in the marathon runners than in non-active people. Achilles tendon thickness has been correlated, in a weak but significant manner, with years of running experience. Moreover, marathon runners showed increased ankle range of motion (81.81 ± 6.93 vs. 77.86 ± 7.27 grades; p<0.01). Conclusion: Male amateur marathon runners have hypertrophy of the Achilles tendon compared to non-active people, and this enlargement is mediated by running experience. In addition, range of motion in ankle dorsiflexion is favored by marathon training. Level of evidence III; Retrospective study.

Reference Values for Acoustic Rhinometry in Subjects without Nasal Symptoms

1998 ◽  
Vol 12 (5) ◽  
pp. 341-344 ◽  
Author(s):  
Eva Millqvist ◽  
Mats Bende
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Reference Values ◽  
Cross Sectional Area ◽  
Acoustic Rhinometry ◽  
Sectional Area ◽  
Cross Sectional ◽  
Nasal Symptoms

Reference values for acoustic rhinometry are presented from 334 individuals without nasal symptoms between 4 years and 61 years old. There was a significant correlation between the minimal cross-sectional area (MCA) and nasal volume. Although the reproducibility of the method was good, the MCA varied widely. MCA correlated weakly to weight, height, age, and body mass index. Our data suggest that acoustic rhinometry is valuable for inter-individual comparisons.

Upper airway morphological changes in obstructive sleep apnoea: effect of age on pharyngeal anatomy

2020 ◽  
Vol 134 (4) ◽  
pp. 354-361
Author(s):  
F Gao ◽  
Y R Li ◽  
W Xu ◽  
Y S An ◽  
H J Wang ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Obstructive Sleep Apnoea ◽  
Upper Airway ◽  
Sleep Apnoea ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Obstructive Sleep ◽  
Airway Morphology

AbstractObjectiveTo evaluate the upper airway morphology changes associated with ageing in adult Chinese patients with obstructive sleep apnoea.MethodsA total of 124 male patients diagnosed with obstructive sleep apnoea by overnight polysomnography, who underwent upper airway computed tomography, were enrolled. The linear dimensions, cross-sectional area and volume of the upper airway region and the surrounding bony frame were measured. The association between ageing and upper airway morphology was analysed.ResultsSoft palate length, minimum cross-sectional area of the retroglossal region, lateral dimensions at the minimum cross-sectional area of the retropalatal and retroglossal regions, nasopharyngeal volume, and average cross-sectional area of the nasopharyngeal region were found to significantly increase with ageing in all patients, while the upper airway shape flattened with ageing. The volume of the retropalatal region increased with ageing among the patients with a body mass index of less than 24 kg/m2. The volume of parapharyngeal fat pad increased with ageing among patients with a body mass index greater than 28 kg/m2.ConclusionA number of dimensional, cross-sectional and volumetric parameters of the pharynx increased with age, indicating that non-anatomical factors may play a more important role in the pathogenesis of obstructive sleep apnoea in aged patients.

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