scholarly journals Functional Morphology and Morphological Diversification of Hind Limb Cross-Sectional Traits in Mustelid Mammals

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
P Parsi-Pour ◽  
B M Kilbourne
Keyword(s):  
Hind Limb ◽  
Structural Strength ◽  
Aquatic Environments ◽  
Sectional Area ◽  
Cross Sectional ◽  
Phylogenetic Relatedness ◽  
Limb Bone ◽  
Limb Bones ◽  
Section Modulus ◽  
Second Moments

Synopsis Locomotor habits in mammals are strongly tied to limb bones’ lengths, diameters, and proportions. By comparison, fewer studies have examined how limb bone cross-sectional traits relate to locomotor habit. Here, we tested whether climbing, digging, and swimming locomotor habits reflect biomechanically meaningful differences in three cross-sectional traits rendered dimensionless— cross-sectional area (CSA), second moments of area (SMA), and section modulus (MOD)—using femora, tibiae, and fibulae of 28 species of mustelid. CSA and SMA represent resistance to axial compression and bending, respectively, whereas MOD represents structural strength. Given the need to counteract buoyancy in aquatic environments and soil’s high density, we predicted that natatorial and fossorial mustelids have higher values of cross-sectional traits. For all three traits, we found that natatorial mustelids have the highest values, followed by fossorial mustelids, with both of these groups significantly differing from scansorial mustelids. However, phylogenetic relatedness strongly influences diversity in cross-sectional morphology, as locomotor habit strongly correlates with phylogeny. Testing whether hind limb bone cross-sectional traits have evolved adaptively, we fit Ornstein–Uhlenbeck (OU) and Brownian motion (BM) models of trait diversification to cross-sectional traits. The cross-sectional traits of the femur, tibia, and fibula appear to have, respectively, diversified under a multi-rate BM model, a single rate BM model, and a multi-optima OU model. In light of recent studies on mustelid body size and elongation, our findings suggest that the mustelid body plan—and perhaps that of other mammals—is likely the sum of a suite of traits evolving under different models of trait diversification.

Effect of Early Low-Intensity Exercise on Rat Hind-Limb Muscles Following Acute Ischemic Stroke

2006 ◽  
Vol 7 (3) ◽  
pp. 163-174 ◽  
Author(s):  
Myoung-Ae Choe ◽  
Gyeong Ju An ◽  
Yoon-Kyong Lee ◽  
Ji Hye Im ◽  
Smi Choi-Kwon ◽  
...  
Keyword(s):  
Hind Limb ◽  
Gastrocnemius Muscle ◽  
Exercise Group ◽  
Cross Sectional Area ◽  
Type I ◽  
Sectional Area ◽  
Muscle Type ◽  
Cross Sectional ◽  
Low Intensity ◽  
Low Intensity Exercise

This study examined the effects of daily low-intensity exercise following acute stroke on mass, Type I and II fiber cross-sectional area, and myofibrillar protein content of hind-limb muscles in a rat model. Adult male Sprague-Dawley rats were randomly assigned to 1 of 4 groups (n = 7-9 per group): stroke (occlusion of the right middle cerebral artery [RMCA]), control (sham RMCA procedure), exercise, and stroke-exercise. Beginning 48 hours post-stroke induction/sham operation, rats in the exercise group had 6 sessions of exercise in which they ran on a treadmill at grade 10 for 20 min/day at 10 m/min. At 8 days poststroke, all rats were anesthetized and soleus, plantaris, and gastrocnemius muscles were dissected from both the affected and unaffected sides. After 6 sessions of exercise following acute ischemic stroke, the stroke-exercise group showed the following significant (p < .05) increases compared to the stroke-only group: body weight and dietary intake, muscle weight of affected soleus and both affected and unaffected gastrocnemius muscle, Type I fiber cross-sectional area of affected soleus and both affected and unaffected gastrocnemius muscle, Type II fiber cross-sectional area of the unaffected soleus, both affected and unaffected plantaris and gastrocnemius muscle, Type II fiber distribution of affected gastrocnemius muscle, and myofibrillar protein content of both affected and unaffected soleus muscle. Daily low-intensity exercise following acute stroke attenuates hind-limb muscle atrophy in both affected and unaffected sides. The effects of exercise are more pronounced in the soleus and gastrocnemius as compared to the plantaris muscle.

Comparison of subchondral lesion size between clinical and non-clinical medial trochlear ridge talar osteochondritis dissecans in dogs

2007 ◽  
Vol 20 (01) ◽  
pp. 08-11 ◽  
Author(s):  
B. Van Ryssen ◽  
F. Coopman ◽  
H. van Bree ◽  
I. Gielen
Keyword(s):  
Osteochondritis Dissecans ◽  
Hind Limb ◽  
Lesion Size ◽  
Degenerative Joint Disease ◽  
Joint Disease ◽  
Bone Lesions ◽  
Sectional Area ◽  
Cross Sectional ◽  
Length Width ◽  
Measured Length

SummaryIn this retrospective study of nine dogs exhibiting bilateral medial trochlear ridge talar osteochondritis dissecans (MTRT-OCD) and unilateral hind limb lameness, we compared subchondral lesion size in limbs with visible lameness, with contralateral lesions that were not associated with any visible lameness. All MTRT-OCD lesions were imaged by radiography and computed tomography (CT). The dimensions of subchondral bone lesions were measured (length, width and depth) using CT software. Similar to a method used in humans, the estimated volume (length x width x depth) and cross sectional area (length x width) were calculated and compared. We found that MTRT-OCD lesions causing visible lameness were significantly larger, and were associated with more joint thickening and degenerative joint disease than contralateral lesions that were not associated with any apparent lameness. As in the disease of shoulder osteochondritis dissecans, there is probably a correlation between the size of MTRT-OCD lesions and the symptoms of lameness.

ASME B31.3 End of Life Considerations: Corrosion, Mechanical Strength, and Small Bore Geometry

2010 ◽  
Author(s):  
Dennis K. Williams
Keyword(s):  
Mechanical Strength ◽  
End Of Life ◽  
Longitudinal Direction ◽  
Careful Examination ◽  
Tabular Form ◽  
Sectional Area ◽  
Cross Sectional ◽  
Section Modulus ◽  
Process Piping ◽  
Thin Walled

This paper discusses the prescribed requirements contained within the ASME B31.3 Process Piping Code that specifically address the considerations of the design corrosion allowance when coincidently taken into account with the mechanical strength requirements of the same. In particular, the most significant effects of the least favorable corrosion allowances in combination with the mechanical strength requirements of ASME B31.3 are prevalent in thin walled, small bore piping of minimal geometric properties associated with the calculation of component stresses in the longitudinal direction. Careful examination of ASME B31.3 paragraph 302.4 reveals that the minimum required thickness of a piping component include allowances for corrosion and when taken in conjunction with paragraph 302.4.1, which requires that when necessary, the wall thickness shall be increased to prevent overstress, damage, or collapse, due to superimposed loads from handling or other causes. The effects of the aforementioned Code requirements are addressed and examples are presented for small bore piping (nps 2″ and below) that lead to a proposed small bore piping criteria for consideration by piping specification engineers. Finally, the results of the evaluation of various combinations of corrosion allowance and mechanical strength requirements in terms of metal cross sectional area and section modulus are presented in tabular form that support the proposed small bore piping criteria.

Age estimation of pteropodid bats (Megachiroptera) from hard tissue parameters

1994 ◽  
Vol 21 (3) ◽  
pp. 353 ◽  
Author(s):  
SM Cool ◽  
MB Bennet ◽  
K Romaniuk
Keyword(s):  
Cross Sections ◽  
Age Estimation ◽  
Hind Limb ◽  
Interference Microscopy ◽  
Long Bones ◽  
Fruit Bats ◽  
Hard Tissue ◽  
Cross Sectional ◽  
Limb Bones ◽  
Radial Thickness

This investigation employed undecalcified thin (10 �m) and thick (100 �m) mid-root sections of surgically removed canine teeth, and thick sections of diaphyseal fore- and hind-limb bones from 14 fruit bats (Pteropus alecto and R poliocephalus) of known age, to attempt to establish a relationship between the chronological age of these animals and changes in the cross-sectional morphology of the hard tissues. Growth layers in bone, dentine and cementum were clearly visible in cross sections when viewed by Nomarski interference microscopy. The number of growth layers in the periosteal region of long bones and in dentine varied widely within a given section, making it impossible to estimate age from these tissues. Dental cementum most reliably reflected the age of fruit bats, with both growth layers and the radial thickness of cementum showing significant correlations with age (P<0.05). Linear regression was used to formulate equations for estimating age. The simplicity of this technique may provide investigators with a useful method for estimating the age of pteropodid fruit bats.

The Skeleton of Giraffes

2021 ◽  
pp. 342-381
Author(s):  
Graham Mitchell
Keyword(s):  
Cervical Vertebrae ◽  
Lumbar Vertebrae ◽  
Average Density ◽  
Cross Sectional Area ◽  
Thoracic Vertebrae ◽  
Sectional Area ◽  
Average Chemical Composition ◽  
Cross Sectional ◽  
Limb Bones ◽  
The Difference

The giraffe skeleton consists of ~170 bones. The dry mass of the skeleton is 70 g.kg-1 body mass. The average chemical composition of their bones is 33% minerals (mainly calcium and phosphorus in a ratio of 2:1), 34% collagen, and 33% water. The skull contributes ~10%, the vertebrae ~25% and the limb bones ~65% to skeleton mass. The average density of all bones is 1.6 g cm-3, ranging from 0.8 g cm-3 (cervical vertebrae) to 2.0 g cm-3 (limb bones). Resistance to fracture by vertebrae depends on their cross-sectional area, and is greatest in cervical and the first few thoracic vertebrae. Resistance to fracture by limb bones depends on wall thickness (the difference between inner and outer diameter), which is uniquely thick. The growth of all limb bones except the humerus follows a geometric pattern (length and diameter increase at the same rate) which confers resistance to compression stress. The humerus follows an elastic pattern (diameter increases faster than length) a pattern that resists bending stress. Giraffes bones are exceptionally straight which further reduces bending stresses. The torque generated by the mass of the head and neck is resisted by the ligamentum nuchae which is exceptionally well-developed in giraffes, extends from the lumbar vertebrae to the occipital crest, can have a diameter of ~10 cm, and can support loads of ~1.8 tonnes before rupturing. As a giraffe grows muscle cross-sectional area (and contraction strength) declines and the duty factor reduces, both of which reduce the risk of fracture.

Ontogenetic scaling of fore limb and hind limb joint posture and limb bone cross-sectional geometry in vervets and baboons

2016 ◽  
Vol 161 (1) ◽  
pp. 72-83 ◽  
Author(s):  
M. Loring Burgess ◽  
Daniel Schmitt ◽  
Angel Zeininger ◽  
Shannon C. McFarlin ◽  
Adrienne L. Zihlman ◽  
...  
Keyword(s):  
Hind Limb ◽  
Cross Sectional ◽  
Limb Bone

Rat locomotory muscle fiber activity during trotting and galloping

1978 ◽  
Vol 44 (3) ◽  
pp. 358-363 ◽  
Author(s):  
T. E. Sullivan ◽  
R. B. Armstrong
Keyword(s):  
Rattus Norvegicus ◽  
Hind Limb ◽  
Fiber Type ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Glycogen Depletion ◽  
Active Muscle ◽  
Cross Sectional ◽  
Limb Muscles ◽  
Whole Muscle

This study was designed to investigate the hypothesis that the trot-gallop transition in running guadrupeds occurs when active cross-sectional areas of muscles or fiber populations within muscles, reach some critical point as animals increase speed within trotting. Rats (Rattus norvegicus) were used as experimental animals, and glycogen depletion was used to estimate patterns or fiber activity. Our results indicate that 1) the contribution to power output by the front limb muscles was less than that of the hind limb muscles during trotting and galloping; 2) the active cross-sectional area of plantaris muscles peaked immediately prior to the transition in gait; 3) the ankle plantar flexor group of muscles as a whole did not attain a maximum active cross-sectional area during fast trotting; and 4) no major discontinuities in whole muscle or fiber type glycogen depletion rates occurred across the gait change. Although these findings do not prove the hypothesis, they support the concept that the trop-gallop transition follows the attainment of peak active muscle cross-sectional areas as animals increase trotting speed.

Structural Strength Benefits Observed at the Hip of Premenarcheal Gymnasts Are Maintained Into Young Adulthood 10 Years After Retirement From the Sport

2017 ◽  
Vol 29 (4) ◽  
pp. 476-485 ◽  
Author(s):  
Marta C. Erlandson ◽  
Shonah B. Runalls ◽  
Stefan A. Jackowski ◽  
Robert A. Faulkner ◽  
Adam D.G. Baxter-Jones
Keyword(s):  
Structural Properties ◽  
Bone Structure ◽  
Femoral Shaft ◽  
Cross Sectional Area ◽  
Analysis Of Covariance ◽  
Sectional Area ◽  
Cross Sectional ◽  
Narrow Neck ◽  
Section Modulus ◽  
Buckling Ratio

Purpose: Premenarcheal female gymnasts have been consistently found to have greater bone mass and structural advantages. However, little is known about whether these structural advantages are maintained after the loading stimulus is removed. Therefore, the purpose of this study was to investigate the structural properties at the hip after long-term retirement from gymnastics. Methods: Structural properties were derived from dual-energy X-ray absorptiometry scans using the hip structural analysis program for the same 24 gymnasts and 21 nongymnasts both in adolescence (8–15 y) and adulthood (22–30 y). Structural measures were obtained at the narrow neck, intertrochanter, and femoral shaft and included cross-sectional area, section modulus, and buckling ratio. Multivariate analysis of covariance was used to assess differences between groups in bone measures while controlling for size, age, maturity, and physical activity. Results: Gymnasts were found to have structural advantages at the narrow neck in adolescence (16% greater cross-sectional area, 17% greater section modulus, and 25% lower buckling ratio) and 14 years later (13% greater cross-sectional area and 26% lower buckling ratio). Benefits were also found at the intertrochanter and femoral shaft sites in adolescence and adulthood. Conclusion: Ten years after retirement from gymnastics, former gymnasts’ maintained significantly better hip bone structure than females who did not participate in gymnastics during growth.

scholarly journals An 8-Year Longitudinal Analysis of Physical Activity and Bone Strength From Adolescence to Emerging Adulthood: The Iowa Bone Development Study

2020 ◽  
Vol 32 (1) ◽  
pp. 58-64 ◽  
Author(s):  
Kristen M. Metcalf ◽  
Elena M. Letuchy ◽  
Steven M. Levy ◽  
Kathleen F. Janz
Keyword(s):  
Physical Activity ◽  
Femoral Neck ◽  
Emerging Adulthood ◽  
Bone Strength ◽  
Biological Age ◽  
Sectional Area ◽  
Strength Index ◽  
Cross Sectional ◽  
Bone Strength Index ◽  
Section Modulus

Purpose: Most pediatric physical activity and bone health research has focused on the period immediately around puberty; few have addressed bone structural strength outcomes. This study assessed the magnitude and consistency of the longitudinal relationships between device-measured vigorous-intensity physical activity (VPA) and structural bone strength outcomes across adolescence to emerging adulthood. Methods: Participants with 3 to 5 bone scans between the age of 11 and 19 years were studied (N = 439, 220 females, 1838 records). Dual-energy X-ray absorptiometry scans of the hip (hip structural analysis) and peripheral quantitative computed tomography scans of the tibia were obtained. Outcomes included femoral neck section modulus, femoral neck cross-sectional area, tibial Bone Strength Index, and tibial torsion strength (polar Strength Strain Index). Sex-specific bone mixed growth models were developed using biological age (chronological age − age at peak height velocity) as the time variable, and height, weight, and device-measured VPA as time-varying covariates. Models also included the VPA–biological age interaction. Results: Individual-centered VPA and the VPA–biological age interaction were significantly, positively associated (P < .05) with Bone Strength Index, polar Strength Strain Index, section modulus, and cross-sectional area in males and females, indicating accumulative effects of VPA throughout maturation and beyond. Conclusion: Bone remains responsive to the mechanical loading of physical activity throughout adolescence and into emerging adulthood. Attention should be placed on promoting bone-strengthening physical activity after the prepubertal years when adult exercise patterns are likely formed.

Sign in / Sign up

Export Citation Format

Share Document