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Journal articles on the topic 'Forelimbs'
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McLaughlin, R. M., J. K. Roush, and Dominique Griffon. "Vertical Ground Reaction Force Redistribution During Experimentally Induced Shoulder Lameness in Dogs." Veterinary and Comparative Orthopaedics and Traumatology 07, no. 04 (1994): 154–57. http://dx.doi.org/10.1055/s-0038-1633089.
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SummaryThe redistribution of vertical ground reaction forces after surgically induced forelimb lameness was evaluated in five Greyhounds at the walk. Vertical ground reaction forces were measured by force plate analysis before, three days, and seven days after a craniolateral approach to the shoulder was performed unilaterally in each dog.At day # 3, peak vertical force was significantly decreased in the operated forelimbs and in the ipsilateral hindlimbs. Peak vertical force was significantly increased in the contralateral fore- and hindlimbs. The total peak vertical force applied to both forelimbs did not change, nor did the total force applied to both hindlimbs. At day # 7, peak vertical force in each of the four limbs had returned to preoperative levels. Results of this study document the redistribution of ground reaction forces (at the walk) between the four limbs in the dog after an acute, surgically induced forelimb lameness.The redistribution of ground reaction force was evaluated in five Greyhounds before and during forelimb lameness. Lameness was induced by a craniolateral approach to one shoulder in each dog. At day # 3 after surgery, peak vertical force was decreased in the operated forelimbs and ipsilateral hindlimbs. Peak vertical force was increased in the contralateral fore- and hindlimbs. The distribution of ground reaction force in the four limbs returned to preoperative values seven days after surgery.
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Giljov, Andrey, Karina Karenina, Margaret Hawkins, and Yegor Malashichev. "First record of limb preferences in monotremes (Zaglossus spp.)." Australian Journal of Zoology 63, no. 5 (2015): 320. http://dx.doi.org/10.1071/zo15043.
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Lateralisation in forelimb use at the population and/or individual level has been found in a wide variety of vertebrate species. However, some large taxa have not yet been investigated and that limits a proper evolutionary interpretation of forelimb preferences. Among mammals lateralised use of the forelimbs has been shown for both placentals and marsupials, but nothing is known about behavioural lateralisation in monotremes. Here we examined lateral preferences in forelimb use in four long-beaked echidnas (male and female Zaglossus bruijni, and male and female Z. bartoni) in captivity. Three individuals showed significant forelimb preferences in unimanual behaviours associated with feeding. When stepping on an eminence with one forelimb first, the lateralisation at the individual level was found only in males of both species. During male–female interactions, the male Z. bartoni significantly preferred to put one of the forelimbs on the female’s back. In both males, the direction of preferences was consistent across different types of behaviour. Our results confirm that manual lateralisation, at least at the individual level, is widespread among mammals. Further research is needed to investigate whether the monotremes display population-level lateralisation in forelimb use.
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Meachen-Samuels, Julie A. "Morphological convergence of the prey-killing arsenal of sabertooth predators." Paleobiology 38, no. 1 (2012): 1–14. http://dx.doi.org/10.1017/s0094837300000373.
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Sabertooth members of the Felidae, Nimravidae, and Barbourofelidae are well-known for their elongated saber-shaped canines. However, within these groups, there is a wide range of independently derived tooth shapes and lengths, including dirk-tooth and scimitar-tooth morphs. In conjunction with the saberteeth, forelimbs were also used to subdue prey. Thus, there may be a functional link between canine shape and forelimb morphology. Because there are no living sabertooth forms for comparison, extant felids make a good proxy for examining the morphology of these extinct organisms. Here, I examine the forelimb morphology of different sabertooth groups from across North America; I address whether forelimb morphologies are associated with tooth morphologies, and whether these associated tooth and forelimb morphologies are convergent among different families. To answer these questions, I analyzed six functional indices of the forelimbs and two canine characters for 13 species of sabertooth predators and 15 extant felid species. Results indicate that sabertooth morphs with longer, thinner canines show more robust limb proportions. These patterns were convergent among sabertooth felids, nimravids, and barbourofelids, and indicate a positive functional relationship between saber elongation and increased forelimb robustness. This suggests that sabertooth carnivorans demonstrated niche partitioning of predation strategies according to canine shape and corresponding forelimb morphology.
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Anderson, Jonathan. "An overview of proximal suspensory ligament desmitis." UK-Vet Equine 3, no. 5 (September 2, 2019): 175–81. http://dx.doi.org/10.12968/ukve.2019.3.5.175.
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Proximal suspensory disease is a common cause of both forelimb and hindlimb lameness and poor performance in the horse. The following article describes the common presentations, diagnostic techniques and treatment options for the condition in both the forelimbs and the hindlimbs.
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Thibaudier, Yann, and Alain Frigon. "Spatiotemporal control of interlimb coordination during transverse split-belt locomotion with 1:1 or 2:1 coupling patterns in intact adult cats." Journal of Neurophysiology 112, no. 8 (October 15, 2014): 2006–18. http://dx.doi.org/10.1152/jn.00236.2014.
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Interlimb coordination must be flexible to adjust to an ever-changing environment. Here adjustments in interlimb coordination were quantified during tied-belt (equal speed of the fore- and hindlimbs) and transverse split-belt (unequal speed of the fore- and hindlimbs) locomotion in five intact adult cats. Cats performed tied-belt locomotion at 0.4 m/s and 0.8 m/s. For transverse split-belt locomotion, the forelimbs stepped at 0.4 m/s and 0.8 m/s while the hindlimbs stepped at 0.8 m/s (4F8H condition) and 0.4 m/s (8F4H condition), respectively. In the 8F4H condition, the forelimbs could take two steps within one hindlimb cycle, or a 2:1 forelimb-hindlimb relationship. The sequence of limbs contacting the ground and the duration of support periods were differentially modified if the forelimbs stepped faster or slower than the hindlimbs. During transverse split-belt locomotion, the hindlimbs performed longer strides when the forelimbs took shorter strides. In the 8F4H condition with a 2:1 forelimb-hindlimb relationship, phase and gap intervals for the first and second steps were found around certain values and were not randomly distributed, indicating that a new coupling pattern was established. However, temporal and spatial coordination indexes revealed that bilateral coordination between hindlimbs was less accurate and more variable with a 2:1 coupling pattern. Importantly, the animals did not stumble, indicating that spatial and temporal adjustments in interlimb coordination allowed the animals to maintain dynamic stability. The results provide a better understanding of the spatiotemporal adjustments that take place among the four limbs during locomotion when interlimb coordination is challenged.
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Reis, Ana Guiomar Matos Santiago, and Raquel Yvonne Arantes Baccarin. "The cross-sectional area of the superficial digital flexor tendon of trained and untrained Thoroughbred racehorses." Ciência Rural 40, no. 8 (August 2010): 1786–90. http://dx.doi.org/10.1590/s0103-84782010000800018.
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Twenty Thoroughbred racehorses were ultrasonographically evaluated to determine the relation between normal values of the cross-sectional area (CSA) of the right and left forelimbs superficial digital flexor tendons (SDFT) in the metacarpal region for trained and untrained Thoroughbreds racehorses. Ultrasonography revealed that CSA at 26cm distal to the accessory carpal bone is larger than other proximal levels, for either left or right forelimbs. In addition, the CSA at 2, 4, 6, 8, 10, 12 and 14cm distal to the accessory carpal bone of the left forelimb are larger (P<0.05) for trained horses when compared with untrained horses. On the other hand, there was no significant difference (P>0.05) between left and right forelimb for CSA of the SDFT, at any level, for either trained or untrained horses, and there was no significant difference between untrained or trained horses for the CSA of right forelimb. In conclusion, the CSA of the left forelimb SDFT for horses that had been in continuous race training remains larger when they were trained anticlockwise, contrary to horses that had not been training for more than one year.
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Courtine, Grégoire, Roland R. Roy, John Hodgson, Heather McKay, Joseph Raven, Hui Zhong, Hong Yang, Mark H. Tuszynski, and V. Reggie Edgerton. "Kinematic and EMG Determinants in Quadrupedal Locomotion of a Non-Human Primate (Rhesus)." Journal of Neurophysiology 93, no. 6 (June 2005): 3127–45. http://dx.doi.org/10.1152/jn.01073.2004.
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We hypothesized that the activation patterns of flexor and extensor muscles and the resulting kinematics of the forelimbs and hindlimbs during locomotion in the Rhesus would have unique characteristics relative to other quadrupedal mammals. Adaptations of limb movements and in motor pool recruitment patterns in accommodating a range of treadmill speeds similar to other terrestrial animals in both the hindlimb and forelimb were observed. Flexor and extensor motor neurons from motor pools in the lumbar segments, however, were more highly coordinated than in the cervical segments. Unlike the lateral sequence characterizing subprimate quadrupedal locomotion, non-human primates use diagonal coordination between the hindlimbs and forelimbs, similar to that observed in humans between the legs and arms. Although there was a high level of coordination between hind- and forelimb locomotion kinematics, limb-specific neural control strategies were evident in the intersegmental coordination patterns and limb endpoint trajectories. Based on limb kinematics and muscle recruitment patterns, it appears that the hindlimbs, and notably the distal extremities, contribute more to body propulsion than the forelimbs. Furthermore, we found adaptive changes in the recruitment patterns of distal muscles in the hind- and forelimb with increased treadmill speed that likely correlate with the anatomical and functional evolution of hand and foot digits in monkeys. Changes in the properties of both the spinal and supraspinal circuitry related to stepping, probably account for the peculiarities in the kinematic and EMG properties during non-human primate locomotion. We suggest that such adaptive changes may have facilitated evolution toward bipedal locomotion.
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Paul, Gregory S., and Per Christiansen. "Forelimb posture in neoceratopsian dinosaurs: implications for gait and locomotion." Paleobiology 26, no. 3 (2000): 450–65. http://dx.doi.org/10.1666/0094-8373(2000)026<0450:fpindi>2.0.co;2.
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Ceratopsid dinosaurs traditionally have been restored with sprawling forelimbs and were considered unable to run at high speeds. An alternative view restores the ceratopsids as rhinoceros-like with parasagittal forelimb kinematics and the ability to run faster than extant elephants. Several anatomical difficulties concerning the mounting of ceratopsid skeletons with nearly parasagittal forelimbs stem not from the forelimb itself, but from errors in rib and vertebral articulation. Matching a skeletal restoration to a probable ceratopsid trackway shows that the hands were placed directly beneath the glenoids, and that manual impressions were directed laterally, not medially as in sprawling reptiles. Pedal impressions in trackways are medial to the manual impressions, owing to the slightly averted elbow and to the asymmetrical distal femoral condyles, which directed the crus slightly medially. The limbs of ceratopsians of all sizes display substantial joint flexure, strongly indicating that the elephantine forelimb posture that has sometimes been suggested as the alternative to a sprawling posture is erroneous. The articular surfaces of uncrushed ceratopsian scapulocoracoids and forelimb joints confirm that the forelimb operated in a near-parasagittal plane with the elbows only slightly averted. The maximal running speed of even the largest ceratopsids is inferred to have significantly exceeded that of elephants and was probably broadly similar to that of rhinos.
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Dróżdż, Dawid. "Osteology of a forelimb of an aetosaurStagonolepis olenkae(Archosauria: Pseudosuchia: Aetosauria) from the Krasiejów locality in Poland and its probable adaptations for a scratch-digging behavior." PeerJ 6 (October 2, 2018): e5595. http://dx.doi.org/10.7717/peerj.5595.
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Aetosaurs are armored basal archosaurs that played a significant role in land ecosystems during the Late Triassic (237–201 Ma). The polish speciesStagonolepis olenkaeSulej, 2010 described from the Krasiejów locality (southern Poland) is one of the oldest known representatives of the group. Abundant and well-preserved material, including partially articulated specimens, allows a detailed description of the forelimbs in this species. The forelimbs ofS. olenkaeare the most similar to that of large aetosaurs likeDesmatosuchus smalli,Desmatosuchus spurensis,Longosuchus meadei,Typothorax coccinarumorStagonolepis robertsoni. Several characters recognized in the forelimbs ofS. olenkaesuggest its adaptation for scratch-digging. The most salient of these features are: short forearm, carpus, and hands, with the radius shorter than the humerus, carpus and manus shorter than the radius (excluding terminal phalanges); a prominent deltopectoral crest that extends distally on the humerus and a wide prominent entepicondyle, a long olecranon process with well-marked attachment of triceps muscle; hooked, laterally compressed, claw-like terminal phalanges with ornamentation of small pits (indicative of well-developed keratin sheaths).S. olenkaemight have used its robust forelimbs to break through the compacted soil with its claws and proceed to dig in search of food in softened substrate with the shovel-like expansion at the tip of its snout. The entire forelimb ofS. olenkaeis covered by osteoderms, including the dorsal surface of the hand, which is unusual among aetosaurs and have not been noted for any species up to date.
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Melville, Jane, Sumitha Hunjan, Felicity McLean, Georgia Mantziou, Katja Boysen, and Laura J. Parry. "Expression of a hindlimb-determining factor Pitx1 in the forelimb of the lizard Pogona vitticeps during morphogenesis." Open Biology 6, no. 10 (October 2016): 160252. http://dx.doi.org/10.1098/rsob.160252.
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With over 9000 species, squamates, which include lizards and snakes, are the largest group of reptiles and second-largest order of vertebrates, spanning a vast array of appendicular skeletal morphology. As such, they provide a promising system for examining developmental and molecular processes underlying limb morphology. Using the central bearded dragon ( Pogona vitticeps ) as the primary study model, we examined limb morphometry throughout embryonic development and characterized the expression of three known developmental genes ( GHR, Pitx1 and Shh ) from early embryonic stage through to hatchling stage via reverse transcription quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC). In this study, all genes were found to be transcribed in both the forelimbs and hindlimbs of P. vitticeps. While the highest level of GHR expression occurred at the hatchling stage, Pitx1 and Shh expression was greatest earlier during embryogenesis, which coincides with the onset of the differentiation between forelimb and hindlimb length. We compared our finding of Pitx1 expression—a hindlimb-determining gene—in the forelimbs of P. vitticeps to that in a closely related Australian agamid lizard, Ctenophorus pictus , where we found Pitx1 expression to be more highly expressed in the hindlimb compared with the forelimb during early and late morphogenesis—a result consistent with that found across other tetrapods. Expression of Pitx1 in forelimbs has only rarely been documented, including via in situ hybridization in a chicken and a frog. Our findings from both RT-qPCR and IHC indicate that further research across a wider range of tetrapods is needed to more fully understand evolutionary variation in molecular processes underlying limb morphology.
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Igarashi, Masakazu, and Jeff Wickens. "Kinematic analysis of bimanual movements during food handling by head-fixed rats." Journal of Neurophysiology 121, no. 2 (February 1, 2019): 490–99. http://dx.doi.org/10.1152/jn.00295.2018.
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Bimanual coordination, in which both hands work together to achieve a goal, is crucial for the basic needs of life, such as gathering and feeding. Such coordinated motor skill is highly developed in primates, where it has been most extensively studied. Rodents also exhibit remarkable dexterity and coordination of forelimbs during food handling and consumption. However, rodents have been less commonly used in the study of bimanual coordination because of limited quantitative measuring techniques. In this article we describe a high-resolution tracking system that enables kinematic analysis of rat forelimb movement. The system is used to quantify forelimb movements bilaterally in head-fixed rats during food handling and consumption. Forelimb movements occurring naturally during feeding were encoded as continuous three-dimensional trajectories. The trajectories were then automatically segmented and analyzed, using a novel algorithm, according to the laterality of movement speed or the asymmetry of movement direction across the forelimbs. Bilateral forelimb movements were frequently observed during spontaneous food handling. Both symmetry and asymmetry in movement direction were frequently observed, with symmetric bilateral movements quantitatively more common. The proposed method overcomes a limitation in the precise quantification of bimanual coordination in rodents. This enables the use of powerful rodent-based research tools such as optogenetics and chemogenetics in the further investigation of neural mechanisms of bimanual coordination. NEW & NOTEWORTHY We describe a new method for quantifying and classifying three-dimensional, bilateral forelimb trajectories in head-fixed rats. The method overcomes limits on quantifying bimanual coordination in rats. When applied to kinematic analysis of food handling behavior, continuous forelimb trajectories were automatically segmented and classified. Bilateral forelimb movements were observed more frequently than unilateral movements during spontaneous food handling. Both symmetry and asymmetry in movement direction were frequently observed. However, symmetric bilateral forelimb movements were more common.
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Amandokht Saghezchi, Shaghayegh, Nahid Azad, Reihane Heidari, Vahid Jajarmi, Shabnam Abdi, Hojjat-Allah Abaszadeh, Seyedeh Susan Sadjadpour, Naheid Neikoei, Mohammad Hassan Heidari, and Mohammad-Amin Abdollahifar. "The Effect of Prenatal Exposure to 2.4 GHz Radio Frequency on the Histology and Expression of the osteocalcin and RUNX2 Gene of the Forelimb in an NMRI Mouse." Journal of Lasers in Medical Sciences 10, no. 4 (October 1, 2019): 283–89. http://dx.doi.org/10.15171/jlms.2019.46.
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Introduction: Today the use of electromagnetic waves has dramatically increased in modern industrial societies. This study aimed to investigate the effect of prenatal exposure to 2.4 GHz wireless frequency on forelimb development in an NMRI mouse in vivo. Methods: A total of 21 female mice weighing 25-30 g were included in the present study. They were randomly assigned to 3 groups, namely control (n=7), sham (n=7), and experimental (n=7). After mating, the experimental group was exposed to 2.4 GHz radio frequency at a distance of 20-30 cm from the device, 4 h/d until the delivery. The sham group was placed at a distance of 20-30 cm from the device every day without exposure to electromagnetic waves, and the control group had a pregnancy period without any stress and electromagnetic wave exposure. After giving birth, the forelimbs were isolated from the infants and examined by stereological studies and RT-PCR for the evaluation of osteocalcin and RUNX2 gene expression. Results: Although, at first glance, there was no macroscopic teratogen effect in forelimbs in all groups, via a stereological method, we showed that bone and cartilage volume decreased in the experimental group compared to the other groups. We also found that the experimental group had lower expression of the osteocalcin and RUNX2 gene than the control and sham groups did. However, there were no significant differences between the control and sham groups in terms of bone and cartilage volume and gene expression. Conclusion: Although teratogen effect of prenatal exposure to 2.4 GHz radio frequency on forelimbs was not demonstrated macroscopically, further studies showed negative effects on the forelimb bone, cartilage volume, and gene expression.
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Lungmus, Jacqueline K., and Kenneth D. Angielczyk. "Antiquity of forelimb ecomorphological diversity in the mammalian stem lineage (Synapsida)." Proceedings of the National Academy of Sciences 116, no. 14 (March 18, 2019): 6903–7. http://dx.doi.org/10.1073/pnas.1802543116.
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Mammals and their closest fossil relatives are unique among tetrapods in expressing a high degree of pectoral girdle and forelimb functional diversity associated with fully pelagic, cursorial, subterranean, volant, and other lifestyles. However, the earliest members of the mammalian stem lineage, the “pelycosaur”-grade synapsids, present a far more limited range of morphologies and inferred functions. The more crownward nonmammaliaform therapsids display novel forelimb morphologies that have been linked to expanded functional diversity, suggesting that the roots of this quintessentially mammalian phenotype can be traced to the pelycosaur–therapsid transition in the Permian period. We quantified morphological disparity of the humerus in pelycosaur-grade synapsids and therapsids using geometric morphometrics. We found that disparity begins to increase concurrently with the emergence of Therapsida, and that it continues to rise until the Permo-Triassic mass extinction. Further, therapsid exploration of new regions of morphospace is correlated with the evolution of novel ecomorphologies, some of which are characterized by changes to overall limb morphology. This evolutionary pattern confirms that nonmammaliaform therapsid forelimbs underwent ecomorphological diversification throughout the Permian, with functional elaboration initially being more strongly expressed in the proximal end of the humerus than the distal end. The role of the forelimbs in the functional diversification of therapsids foreshadows the deployment of forelimb morphofunctional diversity in the evolutionary radiation of mammals.
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Hocking, David P., Felix G. Marx, Renae Sattler, Robert N. Harris, Tahlia I. Pollock, Karina J. Sorrell, Erich M. G. Fitzgerald, Matthew R. McCurry, and Alistair R. Evans. "Clawed forelimbs allow northern seals to eat like their ancient ancestors." Royal Society Open Science 5, no. 4 (April 2018): 172393. http://dx.doi.org/10.1098/rsos.172393.
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Streamlined flippers are often considered the defining feature of seals and sea lions, whose very name ‘pinniped’ comes from the Latin pinna and pedis , meaning ‘fin-footed’. Yet not all pinniped limbs are alike. Whereas otariids (fur seals and sea lions) possess stiff streamlined forelimb flippers, phocine seals (northern true seals) have retained a webbed yet mobile paw bearing sharp claws. Here, we show that captive and wild phocines routinely use these claws to secure prey during processing, enabling seals to tear large fish by stretching them between their teeth and forelimbs. ‘Hold and tear’ processing relies on the primitive forelimb anatomy displayed by phocines, which is also found in the early fossil pinniped Enaliarctos . Phocine forelimb anatomy and behaviour therefore provide a glimpse into how the earliest seals likely fed, and indicate what behaviours may have assisted pinnipeds along their journey from terrestrial to aquatic feeding.
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Liversage, Richard A., Michael J. W. K. Crawford, and Danielle S. McLaughlin. "Effects of concomitant denervation and re-amputation through the regenerative forelimb outgrowth in Xenopus laevis froglets." Canadian Journal of Zoology 64, no. 1 (January 1, 1986): 258–62. http://dx.doi.org/10.1139/z86-041.
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Normally innervated Xenopus laevis froglet forelimbs respond to amputational injury by forming a heteromorphic, cartilaginous spike outgrowth. However, denervation concomitant with amputation of the distal portion of a regenerate outgrowth performed at 1, 2, 3, 4, and 6 weeks after initial forelimb amputation resulted in the regression (resorption) of most, if not all, of the remaining portion of the regenerate tissues. These results indicate that, as in urodele amphibians, concomitantly denervated and amputated forelimb outgrowths of postmetamorphic froglets do not adjust sufficiently to denervation and fresh amputation to allow regeneration to recommence. Instead, progressive resorption of the remaining tissues of the regenerate occurs.
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Wang, Meizi, Yang Song, Stephanie Valentin, Julien S. Baker, and Yaodong Gu. "Kinetic analysis of felines landing from different heights." PeerJ 7 (November 12, 2019): e8007. http://dx.doi.org/10.7717/peerj.8007.
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Background Kinetic motion analysis has been used in canines and equines as a fundamental objective evaluation measurement. Cats are very capable jumpers, and this ability has biomimetic applications. It is essential to understand movement patterns and physical adaptations of this species, as cats are popular pets for humans. Further to this, motion analysis of a cat’s movement patterns may provide potentially valuable information in relation to limb disease and injury. Therefore, the aim of this study was to investigate kinetic differences in cats when landing from varying preselected controlled heights. Methods The peak vertical force (PVF) and paw contact area (CA) of both the forelimbs and hindlimbs were collected from seven healthy Chinese domesticated cats while landing from heights of 30 cm, 50 cm, 70 cm and 90 cm respectively. The falling motivation for the cats was facilitated with the use of a flip board. This device provided the basis for the cats to land passively. Results The results indicated that the PVF of all examined limbs (fore right, fore left, hind right, hind left) significantly increased as the height increased. When the PVF from the hindlimbs and forelimbs were compared, the forelimbs recorded significantly greater values for all heights examined (P < 0.001). The PVF of the hindlimbs was symmetrical at all heights, but forelimb symmetry only occurred at the lower heights. The hindlimbs demonstrated larger CA than the forelimbs measured from all heights on landing (P < 0.001). Moreover, the paw CA on the left and right limbs were symmetrical. Discussion The paw CA of cats may be an effective parameter to evaluate abnormalities or diseases in the limbs of cats. Additionally, these findings highlight how cats land from varying heights, which may also provide reference values for the bionic design of artificial limbs for felines and treatment for limb diseases in this species.
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Liversage, Richard A., and Paul A. Khan. "Ultrastructure of Xenopus laevis forelimbs: effects of denervation and delayed amputation." Canadian Journal of Zoology 68, no. 1 (January 1, 1990): 53–62. http://dx.doi.org/10.1139/z90-010.
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Ultrastructural studies were carried out on left forelimbs of postmetamorphic Xenopus laevis froglets which had been denervated 1 week prior to limb amputation. Limbs were fixed at intervals of 3, 9, and 15 days postamputation. In control and sham-denervated series limbs in which peripheral (brachiospinal) nerves remained intact, tissue regeneration of the amputated forelimb ensued. Extracellular matrix deposition was observed to be minimal among the cells that accumulate subjacent to the wound epithelium of the control and sham cases, not unlike that observed in intact limbs. However, regeneration was not observed in denervated limbs. In denervated forelimbs 9 and 15 days postamputation, deposition of extracellular matrix surrounding the limited fibroblast or fibroblast-like cellular accumulation in the amputated limb stumps was considerably greater than was observed in normally innervated cases. Presumably, extracellular matrix binds fibroblasts together to form scar tissue (cicatrix) which leads to stumping of a denervated, amputated limb. The fibroblasts become narrower, fusiform, and more elongate in denervated nonregenerating forelimbs by 15 days postamputation compared with controls. In all cases fixed 3 days postamputation, epithelial wound healing appeared to proceed normally in the absence of peripheral innervation; also, no ultrastructural difference was observed among amputated control and sham-control limbs that had intact nerves. This investigation is the first to provide a fine-structure analysis of the effects of denervation and delayed amputation on the earlier stages of tissue regeneration in X. laevis froglets.
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Niven, Jeremy E., Swidbert R. Ott, and Stephen M. Rogers. "Visually targeted reaching in horse-head grasshoppers." Proceedings of the Royal Society B: Biological Sciences 279, no. 1743 (July 4, 2012): 3697–705. http://dx.doi.org/10.1098/rspb.2012.0918.
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Visually targeted reaching to a specific object is a demanding neuronal task requiring the translation of the location of the object from a two-dimensionsal set of retinotopic coordinates to a motor pattern that guides a limb to that point in three-dimensional space. This sensorimotor transformation has been intensively studied in mammals, but was not previously thought to occur in animals with smaller nervous systems such as insects. We studied horse-head grasshoppers (Orthoptera: Proscopididae) crossing gaps and found that visual inputs are sufficient for them to target their forelimbs to a foothold on the opposite side of the gap. High-speed video analysis showed that these reaches were targeted accurately and directly to footholds at different locations within the visual field through changes in forelimb trajectory and body position, and did not involve stereotyped searching movements. The proscopids estimated distant locations using peering to generate motion parallax, a monocular distance cue, but appeared to use binocular visual cues to estimate the distance of nearby footholds. Following occlusion of regions of binocular overlap, the proscopids resorted to peering to target reaches even to nearby locations. Monocular cues were sufficient for accurate targeting of the ipsilateral but not the contralateral forelimb. Thus, proscopids are capable not only of the sensorimotor transformations necessary for visually targeted reaching with their forelimbs but also of flexibly using different visual cues to target reaches.
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Simon, H. G., R. Kittappa, P. A. Khan, C. Tsilfidis, R. A. Liversage, and S. Oppenheimer. "A novel family of T-box genes in urodele amphibian limb development and regeneration: candidate genes involved in vertebrate forelimb/hindlimb patterning." Development 124, no. 7 (April 1, 1997): 1355–66. http://dx.doi.org/10.1242/dev.124.7.1355.
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In certain urodeles, a lost appendage, including hand and foot, can be completely replaced through epimorphic regeneration. The regeneration process involves cellular activities similar to those described for embryogenesis. Working on the assumption that the morphological pattern specific for a forelimb or a hindlimb is controlled by different gene activities in the two limbs, we employed a mRNA differential display screen for the detection of candidate limb identity genes. Using this approach, we have isolated a newt gene which in regenerating and developing limbs reveals properties expected of a gene having a role in controlling limb morphology: (1) it is exclusively expressed in the forelimbs, but not hindlimbs, (2) during embryonic development its expression is co-incident with forelimb bud formation, (3) it has an elevated message level throughout the undifferentiated limb bud and the blastema, respectively, and (4) it is expressed only in mesenchymal, but not in epidermal tissues. This novel newt gene shares a conserved DNA-binding domain, the T-box, with putative transcription factors including the Brachyury (T) gene product. In a following PCR-based screen, we used the evolutionarily conserved T-box motif and amplified a family of related genes in the newt; their different expression patterns in normal and regenerating forelimbs, hindlimbs and tail suggest, in general, an important role of T-domain proteins in vertebrate pattern formation.
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Graf, Peter, and H. U. Steinau. "REPLANTATION OF CANINE FORELIMBS." Plastic and Reconstructive Surgery 86, no. 2 (August 1990): 383. http://dx.doi.org/10.1097/00006534-199008000-00051.
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Janis, Christine M., James G. Napoli, Coral Billingham, and Alberto Martín-Serra. "Proximal Humerus Morphology Indicates Divergent Patterns of Locomotion in Extinct Giant Kangaroos." Journal of Mammalian Evolution 27, no. 4 (January 16, 2020): 627–47. http://dx.doi.org/10.1007/s10914-019-09494-5.
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Abstract Sthenurine kangaroos, extinct “giant kangaroos” known predominantly from the Plio-Pleistocene, have been proposed to have used bipedal striding as a mode of locomotion, based on the morphology of their hind limbs. However, sthenurine forelimb morphology has not been considered in this context, and has important bearing as to whether these kangaroos employed quadrupedal or pentapedal locomotion as a slow gait, as in extant kangaroos. Study of the correlation of morphology of the proximal humerus in a broad range of therian mammals shows that humeral morphology is indicative of the degree of weight-bearing on the forelimbs during locomotion, with terrestrial species being distinctly different from arboreal ones. Extant kangaroos have a proximal humeral morphology similar to extant scansorial (semi-arboreal) mammals, but sthenurine humeri resemble those of suspensory arboreal taxa, which rarely bear weight on their forelimbs, supporting the hypothesis that they used bipedal striding rather than quadrupedal locomotion at slow gaits. The humeral morphology of the enigmatic extinct “giant wallaby,” Protemnodon, may be indicative of a greater extent of quadrupedal locomotion than in extant kangaroos.
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Liao, Wen Bo, Qing Gui Wu, and Kyle Barrett. "Evolution of sexual dimorphism in the forelimb muscles of Andrew's toad (Bufo andrewsi) in response to putative sexual selection." Animal Biology 62, no. 1 (2012): 83–93. http://dx.doi.org/10.1163/157075611x616879.
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AbstractSexual differences in morphological traits are widespread among animals. Theory predicts that dimorphism in secondary sexual characters evolves as a consequence of sexual selection. We investigated the intersexual difference in mass of forelimb muscles of the Andrew's toad, Bufo andrewsi, an elongated species inhabiting montane regions in western China. Our results showed that average body size of females was significantly larger than males. However, when the influence of body size was removed, the forelimb muscle mass of males significantly exceeded that of females, and total mass of forelimb muscles of amplectant males was significantly larger than that of non-amplectant males. These results suggest that the robustness of the forelimbs can allow amplectant males to retain a firm grip on the female in amplexus, which may aid resistance to inference by conspecific males. Our findings are consistent with the prediction that sexual selection favors large forelimb muscle mass in males.
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Giszter, Simon F., Michelle R. Davies, and Virginia Graziani. "Motor Strategies Used by Rats Spinalized at Birth to Maintain Stance in Response to Imposed Perturbations." Journal of Neurophysiology 97, no. 4 (April 2007): 2663–75. http://dx.doi.org/10.1152/jn.00308.2006.
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Some rats spinalized P1/P2 achieve autonomous weight-supported locomotion and quiet stance as adults. We used force platforms and robot-applied perturbations to test such spinalized rats ( n = 6) that exhibited both weight-supporting locomotion and stance, and also normal rats ( n = 8). Ground reaction forces in individual limbs and the animals' center of pressure were examined. In normal rats, both forelimbs and hindlimbs participated actively to control horizontal components of ground reaction forces. Rostral perturbations increased forelimb ground reaction forces and caudal perturbations increased hindlimb ground reaction forces. Operate rats carried 60% body weight on the forelimbs and had a more rostral center of pressure placement. The pattern in normal rats was to carry significantly more weight on the hindlimbs in quiet stance (roughly 60%). The strategy of operate rats to compensate for perturbations was entirely in forelimbs; as a result, the hindlimbs were largely isolated from the perturbation. Stiffness magnitude of the whole body was measured: its magnitude was hourglass shaped, with the principal axis oriented rostrocaudally. Operate rats were significantly less stiff—only 60–75% of normal rats' stiffness. The injured rats adopt a stance strategy that isolates the hindlimbs from perturbation and may thus prevent hindlimb loadings. Such loadings could initiate reflex stepping, which we observed. This might activate lumbar pattern generators used in their locomotion. Adult spinalized rats never achieve independent hindlimb weight-supported stance. The stance strategy of the P1 spinalized rats differed strongly from the behavior of intact rats and may be difficult for rats spinalized as adults to master.
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Peterson, Michael, Wayne Sanderson, Nurlan Kussainov, Sarah Jane Hobbs, Patti Miles, Mary C. Scollay, and Hilary M. Clayton. "Effects of Racing Surface and Turn Radius on Fatal Limb Fractures in Thoroughbred Racehorses." Sustainability 13, no. 2 (January 8, 2021): 539. http://dx.doi.org/10.3390/su13020539.
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North American Thoroughbred racing is conducted on three types of surfaces—dirt, turf, and synthetic. The tracks are oval, and races are run counterclockwise. The loading on right and left limbs is expected to differ as a function of turn radius, banking, surface, and gait asymmetry. Hind limbs and forelimbs also have different functions related to propulsion and turning, respectively. This study uses the Equine Injury Database for race starts from 1 January 2009 through 31 December 2014, to compare injury rates across participating North American racetracks. The data are limited to catastrophic injuries in which horses died or were euthanized due to a fracture within 72 h of the start of the race. Overall injury rates were lower on turf and synthetic surfaces and the pattern of limb injuries in left vs. right and fore vs. hind limbs were different. Regardless of surface, forelimbs were more likely to fracture. Dirt surfaces showed higher rates of forelimb injuries compared to other surfaces, hind limbs were more likely to experience a fatal fracture on turf than on dirt. The left fore and right hind limbs were more likely to experience a fatal fracture but only on dirt surfaces.
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Gillis, Gary B., Trupti Akella, and Rashmi Gunaratne. "Do toads have a jump on how far they hop? Pre-landing activity timing and intensity in forelimb muscles of hopping Bufo marinus." Biology Letters 6, no. 4 (February 3, 2010): 486–89. http://dx.doi.org/10.1098/rsbl.2009.1005.
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During jumping or falling in humans and various other mammals, limb muscles are activated before landing, and the intensity and timing of this pre-landing activity are scaled to the expected impact. In this study, we test whether similarly tuned anticipatory muscle activity is present in hopping cane toads. Toads use their forelimbs for landing, and we analysed pre-landing electromyographic (EMG) timing and intensity in relation to hop distance for the m. coracoradialis and m. anconeus , which act antagonistically at the elbow, and are presumably important in stabilizing the forelimb during landing. In most cases, a significant, positive relationship between hop distance and pre-landing EMG intensity was found. Moreover, pre-landing activation timing of m. anconeus was tightly linked to when the forelimbs touched down at landing. Thus, like mammals, toads appear to gauge the timing and magnitude of their impending impact and activate elbow muscles accordingly. To our knowledge these data represent the first demonstration of tuned pre-landing muscle recruitment in anurans and raise questions about how important the visual, vestibular and/or proprioceptive systems are in mediating this response.
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Alves, Flávio Ribeiro, Porfírio Candanedo Guerra, Emerson Ticona Fioretto, Antônio Augusto Nascimento Machado Júnior, Felicianna Clara Fonseca Machado, Rosany Maria Cunha Aranha, Carlos Eduardo Ambrósio, Arani Nanci Bomfim Mariana, and Maria Angélica Miglino. "Angiographic aspect of the distal forelimb in donkeys (Equus asinus) used for animal traction." Biotemas 22, no. 4 (January 1, 2009): 163. http://dx.doi.org/10.5007/2175-7925.2009v22n4p163.
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http://dx.doi.org/10.5007/2175-7925.2009v22n4p163The asinine species was originated thousands of years ago from the same branch of domestic equine. Asinines have been undergoing a great adaptation resulting in different characteristics observed in their populations around the world. In the northeastern region of Brazil, they play an essential role in the economy of local families. Due to a large number of locomotor disorders and a lacN of professional care for these animals, a radiographic study of the distal forelimb region of the asinine was carried out in order to gather information for the improvement of clinical and surgical practices in this species, and to explain their low susceptibility to locomotor disorders compared to that of the domestic equine. The angiographic examination revealed the main arterial vessels committed to the blood supply of the forelimbs in these animals, providing evidence of the vascular pattern of the median and palmar common digital arteries, which originated a great number of collateral branches, mainly to the distal phalanx. The distal forelimbs in donNeys have shown great vascular anastomosis, promoting additional blood supply to the deep endosteum and periosteum regions, probably as a response to the physical activity developed by these animals.
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Peterson, Michael, Wayne Sanderson, Nurlan Kussainov, Sarah Jane Hobbs, Patti Miles, Mary C. Scollay, and Hilary M. Clayton. "Effects of Racing Surface and Turn Radius on Fatal Limb Fractures in Thoroughbred Racehorses." Sustainability 13, no. 2 (January 8, 2021): 539. http://dx.doi.org/10.3390/su13020539.
Full textAbstract:
North American Thoroughbred racing is conducted on three types of surfaces—dirt, turf, and synthetic. The tracks are oval, and races are run counterclockwise. The loading on right and left limbs is expected to differ as a function of turn radius, banking, surface, and gait asymmetry. Hind limbs and forelimbs also have different functions related to propulsion and turning, respectively. This study uses the Equine Injury Database for race starts from 1 January 2009 through 31 December 2014, to compare injury rates across participating North American racetracks. The data are limited to catastrophic injuries in which horses died or were euthanized due to a fracture within 72 h of the start of the race. Overall injury rates were lower on turf and synthetic surfaces and the pattern of limb injuries in left vs. right and fore vs. hind limbs were different. Regardless of surface, forelimbs were more likely to fracture. Dirt surfaces showed higher rates of forelimb injuries compared to other surfaces, hind limbs were more likely to experience a fatal fracture on turf than on dirt. The left fore and right hind limbs were more likely to experience a fatal fracture but only on dirt surfaces.
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Lima, Alfredo Feio da Maia, Sheila Canevese Rahal, Reinaldo dos Santos Volpi, José Mauro Granjeiro, Rumio Taga, and Tania Maria Cestari. "Effect of bovine bone morphogenetic proteins on radius fracture healing in rabbits." Acta Cirurgica Brasileira 22, no. 4 (August 2007): 260–65. http://dx.doi.org/10.1590/s0102-86502007000400006.
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PURPOSE: To investigate the effect of bovine bone morphogenetic proteins (bBMPs) bound to hydroxyapatite plus collagen in the healing of unstable radius fractures. METHODS: A transverse fracture was induced at the mid of the diaphysis in both radii on 15 Norfolk rabbits with average age of 5.5 months and 3.5kg. A mixture of bBMPs bound to thin powdered hydroxyapatite (bBMP-HA) and bovine collagen as agglutinant was applied to the right radius fracture site. The left radius fracture was considered control and no treatment was used. After 30, 60 and 90 days (5 rabbits/period) the rabbits were euthanized and the radii were collected for histological analysis. RESULTS: The descriptive histological analysis revealed that repair was similar for both forelimbs. The histomorphometric analysis showed that the mean area of newly formed bone was 867442.16 mm², 938743.00 mm² and 779621.06 mm² for the control forelimbs, and 841118.47 mm², 788038.76mm² and 618587.24 mm² for the treated forelimbs at 30, 60 and 90 days, respectively. Thus the newly formed bone area was 12.17% larger in the forelimbs treated with bBMP-HA/collagen than in the control forelimbs (p<0.05, Tukey test) in the 60-day period after surgery. In both forelimbs the newly formed bone area increased throughout the experimental period until the complete fracture healing. CONCLUSION: Based on the result obtained here we concluded that bBMP-HA/collagen induced a lower but significant improvement in fracture consolidation.
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SMITH, A. M., J. A. FORDER, S. R. ANNAPUREDDY, K. S. K. REDDY, and A. A. AMIS. "The Porcine Forelimb as a Model for Human Flexor Tendon Surgery." Journal of Hand Surgery 30, no. 3 (June 2005): 307–9. http://dx.doi.org/10.1016/j.jhsb.2005.02.003.
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Technical skills have been shown to transfer very well from bench models to practical use. The central two rays of 30 forelimbs of pigs were dissected and anatomical observations were made. The rays contained deep and superficial flexor tendons enclosed in a fibro-osseous tunnel and these were present in all 60 specimens. The fibrous part of the tunnel had specific constant condensations in annular and oblique directions which were present in all 60 rays. The anatomy of the porcine forelimb digital flexor tendon system is sufficiently similar to the human system to be used as a model for surgeons wishing to master the technical aspects of zone II flexor tendon repair. This paper proposes the porcine forelimb as a bench model for zone II flexor tendon repair.
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Collard, Mark, and Leslie C. Aiello. "From forelimbs to two legs." Nature 404, no. 6776 (March 2000): 339–40. http://dx.doi.org/10.1038/35006181.
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Lee, D. V., J. E. Bertram, and R. J. Todhunter. "Acceleration and balance in trotting dogs." Journal of Experimental Biology 202, no. 24 (December 15, 1999): 3565–73. http://dx.doi.org/10.1242/jeb.202.24.3565.
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During quadrupedal trotting, diagonal pairs of limbs are set down in unison and exert forces on the ground simultaneously. Ground-reaction forces on individual limbs of trotting dogs were measured separately using a series of four force platforms. Vertical and fore-aft impulses were determined for each limb from the force/time recordings. When mean fore-aft acceleration of the body was zero in a given trotting step (steady state), the fraction of vertical impulse on the forelimb was equal to the fraction of body weight supported by the forelimbs during standing (approximately 60 %). When dogs accelerated or decelerated during a trotting step, the vertical impulse was redistributed to the hindlimb or forelimb, respectively. This redistribution of the vertical impulse is due to a moment exerted about the pitch axis of the body by fore-aft accelerating and decelerating forces. Vertical forces exerted by the forelimb and hindlimb resist this pitching moment, providing stability during fore-aft acceleration and deceleration.
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Cho, Hee Kyung, Woo Jung Sung, Youn Ju Lee, Sang Gyu Kwak, and Kang Lip Kim. "Two methods of extracorporeal shock-wave therapy in a rat model of secondary lymphedema: a pilot study." Journal of International Medical Research 49, no. 6 (June 2021): 030006052110244. http://dx.doi.org/10.1177/03000605211024473.
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Objectives To compare the effectiveness of two methods of extracorporeal shock-wave therapy (ESWT) in a rat model of forelimb lymphedema, induced by axillary lymph node dissection. Methods Sprague–Dawley rats were randomly allocated to a group that received 500 ESWT shocks only in the lymphedematous forelimb (Forelimb/ESWT) and a group that received 300 ESWT shocks in the axilla and 200 shocks in the lymphedematous forelimb (Axilla+Forelimb/ESWT). The circumferences of each limb were then measured. Immunohistochemistry for a pan-endothelial marker (cluster of differentiation [CD]31) and lymphatic vessel endothelial hyaluronan receptor-1, and western blot analysis for vascular endothelial growth factor receptor-3 (VEGFR3) and VEGF-C were performed. Results The circumferences of the limbs showed significant effects of group and time following surgery. The circumferences at the carpal joint and 2.5 cm above were smallest in the naïve limbs, larger in the Axilla+Forelimb/ESWT group, and the largest in the control group. VEGFR3 tended to be expressed at a higher level in the Axilla+Forelimb/ESWT group (1.96-fold) than in the Forelimb/ESWT group (1.20-fold) versus the opposite non-edematous forelimbs, although this difference was not statistically significant. Conclusions These data suggest that ESWT protocols have differential effects on angiogenesis and lymphangiogenesis in lymphedematous limbs.
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Yegian, Andrew K., Yanish Tucker, Stephen Gillinov, and Daniel E. Lieberman. "Shorter distal forelimbs benefit bipedal walking and running mechanics: Implications for hominin forelimb evolution." American Journal of Physical Anthropology 175, no. 3 (April 5, 2021): 589–98. http://dx.doi.org/10.1002/ajpa.24274.
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Cooper, W. James, and Scott J. Steppan. "Developmental constraint on the evolution of marsupial forelimb morphology." Australian Journal of Zoology 58, no. 1 (2010): 1. http://dx.doi.org/10.1071/zo09102.
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Compared with the placental mammals, marsupials are born at an almost embryonic stage, but nearly all of these neonates immediately climb or crawl to one of their mother’s teats using precociously developed forelimbs. Marsupial adults also exhibit limited forelimb shape diversity relative to the members of their sister group. That the functional requirements of this natal climb have imposed a developmental constraint on marsupial forelimb evolution represents a compelling and widely accepted hypothesis, yet its resulting predictions for the comparative patterns of mammal limb shape diversity have never been tested. In order to perform such tests we conducted extensive taxonomic sampling of mammal limb morphology (including fossil specimens), and then examined these data using morphometric methods, non-parametric analyses of anatomical disparity, and phylogenetic comparative analyses of evolutionary rates. Our results strongly support the constraint hypothesis, and indicate that the highly significant differences between marsupial and placental forelimb shape diversity has been strongly influenced by different rates of morphological evolution among the distal forelimb elements in these two important mammal lineages.
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Frigon, Alain. "The neural control of interlimb coordination during mammalian locomotion." Journal of Neurophysiology 117, no. 6 (June 1, 2017): 2224–41. http://dx.doi.org/10.1152/jn.00978.2016.
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Neuronal networks within the spinal cord directly control rhythmic movements of the arms/forelimbs and legs/hindlimbs during locomotion in mammals. For an effective locomotion, these networks must be flexibly coordinated to allow for various gait patterns and independent use of the arms/forelimbs. This coordination can be accomplished by mechanisms intrinsic to the spinal cord, somatosensory feedback from the limbs, and various supraspinal pathways. Incomplete spinal cord injury disrupts some of the pathways and structures involved in interlimb coordination, often leading to a disruption in the coordination between the arms/forelimbs and legs/hindlimbs in animal models and in humans. However, experimental spinal lesions in animal models to uncover the mechanisms coordinating the limbs have limitations due to compensatory mechanisms and strategies, redundant systems of control, and plasticity within remaining circuits. The purpose of this review is to provide a general overview and critical discussion of experimental studies that have investigated the neural mechanisms involved in coordinating the arms/forelimbs and legs/hindlimbs during mammalian locomotion.
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Schmidt, Katy, Catherine Hughes, J. A. Chudek, Simon R. Goodyear, Richard M. Aspden, Richard Talbot, Thomas E. Gundersen, et al. "Cholesterol Metabolism: the Main Pathway Acting Downstream of Cytochrome P450 Oxidoreductase in Skeletal Development of the Limb." Molecular and Cellular Biology 29, no. 10 (March 9, 2009): 2716–29. http://dx.doi.org/10.1128/mcb.01638-08.
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ABSTRACT Cytochrome P450 oxidoreductase (POR) is the obligate electron donor for all microsomal cytochrome P450 enzymes, which catalyze the metabolism of a wide spectrum of xenobiotic and endobiotic compounds. Point mutations in POR have been found recently in patients with Antley-Bixler-like syndrome, which includes limb skeletal defects. In order to study P450 function during limb and skeletal development, we deleted POR specifically in mouse limb bud mesenchyme. Forelimbs and hind limbs in conditional knockout (CKO) mice were short with thin skeletal elements and fused joints. POR deletion occurred earlier in forelimbs than in hind limbs, leading additionally to soft tissue syndactyly and loss of wrist elements and phalanges due to changes in growth, cell death, and skeletal segmentation. Transcriptional analysis of E12.5 mouse forelimb buds demonstrated the expression of P450s involved in retinoic acid, cholesterol, and arachidonic acid metabolism. Biochemical analysis of CKO limbs confirmed retinoic acid excess. In CKO limbs, expression of genes throughout the whole cholesterol biosynthetic pathway was upregulated, and cholesterol deficiency can explain most aspects of the phenotype. Thus, cellular POR-dependent cholesterol synthesis is essential during limb and skeletal development. Modulation of P450 activity could contribute to susceptibility of the embryo and developing organs to teratogenesis.
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Muza, S. R., G. J. Criner, and S. G. Kelsen. "Effect of lung volume on the respiratory action of the canine pectoral muscles." Journal of Applied Physiology 73, no. 6 (December 1, 1992): 2408–12. http://dx.doi.org/10.1152/jappl.1992.73.6.2408.
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Lung volume influences the mechanical action of the primary inspiratory and expiratory muscles by affecting their precontraction length, alignment with the rib cage, and mechanical coupling to agonistic and antagonistic muscles. We have previously shown that the canine pectoral muscles exert an expiratory action on the rib cage when the forelimbs are at the torso's side and an inspiratory action when the forelimbs are held elevated. To determine the effect of lung volume on intrathoracic pressure changes produced by the canine pectoral muscles, we performed isolated bilateral supramaximal electrical stimulation of the deep pectoral and superficial pectoralis (descending and transverse heads) muscles in 15 adult supine anesthetized dogs during hyperventilation-induced apnea. Lung volume was altered by application of a negative or positive pressure (+/- 30 cmH2O) to the airway. In all animals, selective electrical stimulation of the descending, transverse, and deep pectoral muscles with the forelimbs held elevated produced negative intrathoracic pressure changes (i.e., an inspiratory action). Moreover, with the forelimbs elevated, increasing lung volume decreased both pectoral muscle fiber precontraction length and the negative intrathoracic pressure changes generated by contraction of each of these muscles. Conversely, with the forelimbs along the torso, increasing lung volume lengthened pectoral muscle precontraction length and augmented the positive intrathoracic pressure changes produced by muscle contraction (i.e., an expiratory action). These results indicate that lung volume significantly affects the length of the canine pectoral muscles and their mechanical actions on the rib cage.
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Iwaniuk, Andrew N., Sergio M. Pellis, and Ian Q. Whishaw. "The relationship between forelimb morphology and behaviour in North American carnivores (Carnivora)." Canadian Journal of Zoology 77, no. 7 (October 20, 1999): 1064–74. http://dx.doi.org/10.1139/z99-082.
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We tested the validity of previously described relationships between forelimb structure and behaviour in mammals by measuring the forelimbs of 22 species of North American carnivores. Nine ratios were calculated from these measurements and made independent of the effects of allometry and phylogeny through the use of log-transformed regressions and independent contrasts analysis. The ratios were then directly compared with two behavioural traits: arboreal locomotion and vertebrate predation. Only five of the nine ratios exhibited a significant relationship with arboreal locomotion and three with vertebrate predation. It was concluded that the brachial index, relative size of the olecranon process, and total forelimb robusticity may be reliable predictors of arboreal locomotion, and that the brachial index, relative size of the olecranon process, and radial robusticity may be accurate predictors of vertebrate predation. The data also suggest that the morphology of the lower forelimb may be an important indicator of prey-capture and feeding behaviour in carnivores and could be used in conjunction with craniodental variables to extrapolate predatory behaviour of extinct species.
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Hungerbühler, Stephan, Wolfgang Henninger, Petra Klupiec, Julia Bödeker, Anna Langer, Michael Fehr, Oliver Harms, and Julia Ungru. "Diagnosis and treatment of infraspinatus tendon-bursa ossification in a Eurasian Dog." Tierärztliche Praxis Ausgabe K: Kleintiere / Heimtiere 46, no. 02 (April 2018): 126–32. http://dx.doi.org/10.15654/tpk-170156.
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SummaryA 4-year-old male Eurasian Dog presented at our veterinary clinic with a history of perpetual forelimb lameness in both thoracic limbs. In the clinical exploration, direct pressure over the infraspinatus tendon of insertion caused pain in both thoracic forelimbs and a firm band-like structure was palpable. No improvement was observed after treatment with rest, non-steroidal anti-inflammatory drugs and an intralesional injection of a long-acting glucocorticoid. Radiographic examination, ultrasonographic exploration and computed tomography were performed, identifying ossified structures lateral to the proximal humerus and an irregular roughened periosteum at the insertion and tendon of the infraspinatus muscle on both sides. There were more distinct alterations on the right thoracic limb. The imaging results led to a diagnosis of an infraspinatus tendon-bursa ossification accompanied by a chronic tendinopathy/tendovaginitis, accentuated on the right side. The dog was subjected to physiotherapy and autologous conditioned plasma (ACP) was injected into the insertion of the infraspinatus muscle of both thoracic limbs. After 5 months of physiotherapy and two injections of ACP with an interval of one week in both forelimbs, the dog showed no signs of lameness. This case report describes the diagnosis and management of infraspinatus tendon-bursa ossification in a Eurasian Dog. To the authors’ knowledge, this condition has previously not been described in this breed of dog.
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Renous, Sabine, and Vincent Bels. "Étude cinématique de la palette natatoire antérieure de la tortue Luth, Dermochelys coriacea (Vandelli, 1761), au cours de sa locomotion terrestre." Canadian Journal of Zoology 69, no. 2 (February 1, 1991): 495–503. http://dx.doi.org/10.1139/z91-076.
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The leatherback turtle, Dermochelys coriacea, which is particularly well adapted to marine life, uses a mode of terrestrial locomotion that does not involve raising the entire body; it drags itself instead, which is unique to heavy animals. The primary pattern of tetrapods, using alternate movements and a diagonal sequence of the limbs, is replaced by a specific repertory of periodic and synchronous movements of the fore- and hind-limbs. The forelimbs, which have evolved into large paddles, produce lifting and forward movements of the body as if the turtle were "walking on crutches." During terrestrial locomotion, the forelimb movement, derived from swimming, is rather similar to that used during vigorous swimming, except for a reduction of the upstroke.
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Goss, Richard J., and Roger Holt. "Epimorphic vs. tissue regeneration inXenopus forelimbs." Journal of Experimental Zoology 261, no. 4 (April 1, 1992): 451–57. http://dx.doi.org/10.1002/jez.1402610412.
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Funston, Gregory F., Tsogtbaatar Chinzorig, Khishigjav Tsogtbaatar, Yoshitsugu Kobayashi, Corwin Sullivan, and Philip J. Currie. "A new two-fingered dinosaur sheds light on the radiation of Oviraptorosauria." Royal Society Open Science 7, no. 10 (October 2020): 201184. http://dx.doi.org/10.1098/rsos.201184.
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Late Cretaceous trends in Asian dinosaur diversity are poorly understood, but recent discoveries have documented a radiation of oviraptorosaur theropods in China and Mongolia. However, little work has addressed the factors that facilitated this diversification. A new oviraptorid from the Late Cretaceous of Mongolia sheds light on the evolution of the forelimb, which appears to have played a role in the radiation of oviraptorosaurs. Surprisingly, the reduced arm has only two functional digits, highlighting a previously unrecognized occurrence of digit loss in theropods. Phylogenetic analysis shows that the onset of this reduction coincides with the radiation of heyuannine oviraptorids, following dispersal from southern China into the Gobi region. This suggests expansion into a new niche in the Gobi region, which relied less on the elongate, grasping forelimbs inherited by oviraptorosaurs. Variation in forelimb length and manus morphology provides another example of niche partitioning in oviraptorosaurs, which may have made possible their incredible diversity in the latest Cretaceous of Asia.
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Willemen, M. A., J. L. Lanovaz, H. C. Schamhardt, and Hilary Clayton. "Effects of a Heel Wedge in Horses with Superficial Digital Flexor Tendinitis." Veterinary and Comparative Orthopaedics and Traumatology 13, no. 01 (2000): 01–08. http://dx.doi.org/10.1055/s-0038-1632622.
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SummaryThe objective was to determine whether the use of heel wedges is an appropriate treatment for superficial digital flexor (SDF) tendinitis. The subjects were six warmblood horses in which SDF tendinitis was induced in one forelimb using a collagenase model. The stride characteristics were compared under four conditions: flat shoes; 6° heel wedge following a one hour adaptation; 6° heel wedge following five days adaptation; and one hour after reapplication of flat shoes. Videographic and force data were collected for both forelimbs during the stance phase of the trot, and were combined with morphometric measurements using an inverse dynamics method to calculate net joint moments and joint powers at each of the joints of the forelimbs. Repeated measures ANOVA was used to compare the stride variables across conditions in the lame limb and in the compensating forelimb. Significant kinematic changes in response to the use of heel wedges were confined to the coffin joint which was more flexed due to the more upright orientation of the hoof segment. The onset of breakover was delayed with the hoof wedges. In the compensating limb only, the use of heel wedges was associated with a shift of the net joint moment to the dorsal side of the coffin joint during the first one third of stance. Both forelimbs had significantly smaller peak palmar moments at the coffin joint with heel wedges in the second half of stance, which appeared to be a mechanical consequence of the more flexed position of the coffin joint. Tension was increased in the extensor branches of the suspensory ligament and common digital extensor tendon on the dorsal side, and reduced in the deep digital flexor tendon and its distal accessory ligament on the palmar side. Less energy was absorbed across the coffin joint in both limbs with heel wedges. The study did not reveal changes associated with the use of heel wedges that could be interpreted as a reduction of the effects of lameness due to SDF tendinitis.The objective was to determine whether the application of 60 heel wedges was appropriate for treating horses with superficial digital flexor (SDF) tendinitis. The significant effects of the heel wedges affected the coffin joint and included a more flexed position due to the more upright orientation of the hoof segment, a reduction in the peak palmar moment and less energy absorption across the joint. Since these changes were confined to the coffin joint, they were not interpreted as being beneficial in treating lameness due to SDF tendinitis.
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Dobney, J. A., M. R. Owen, G. R. Colborne, and N. J. Burton. "Joint angle, moment and power compensations in dogs with fragmented medial coronoid process." Veterinary and Comparative Orthopaedics and Traumatology 21, no. 02 (2008): 110–18. http://dx.doi.org/10.3415/vcot-07-04-0038.
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SummaryFragmented medial coronoid process (FMCP) is the most common cause of forelimb lameness in juvenile medium and large breed dogs; however methods of assessing the disruption to their gait remain subjective. The purpose of this study was to objectively quantify the mechanical disruptions to gait in dogs with arthroscopically confirmed unilateral FMCP. Seven dogs underwent full inverse dynamic analysis at the time of diagnosis. Kinematic and force data were collected from both forelimbs at trot. Stance phase joint angles, net joint moments and net joint powers were calculated using custom software. There were gross differences in kinetic and kinematic patterns between FMCP affected and compensating forelimbs. Stance time was 0.24 sec on the lame side and 0.26 sec on the compensating side. The shoulder and the elbow were more flexed at ground contact, and elbow, carpal and MCP joints had smaller ranges of motion on the lame side. Net joint moments were significantly reduced (P<0.05) in the elbow, carpal and MCP joints of the FMCP affected limb. Net joint powers were likewise significantly smaller (P<0.05). However, the overall moment and power patterns persisted. Total limb support moment was significantly smaller on the affected side (P<0.05). Total limb power was significantly reduced on the affected side (P<0.05) being most affected in its propulsive phase in the second half of stance. Inverse dynamic analysis of this clinical condition is an objective means by which to assess the mechanical disruption to gait.
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Pace, Cinnamon M., Richard W. Blob, and Mark W. Westneat. "Comparative kinematics of the forelimb during swimming in red-eared slider (Trachemys scripta) and spiny softshell (Apalone spinifera) turtles." Journal of Experimental Biology 204, no. 19 (October 1, 2001): 3261–71. http://dx.doi.org/10.1242/jeb.204.19.3261.
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SUMMARYSoftshell turtles (Family Trionychidae) possess extensive webbing between the digits of the manus, suggesting that the forelimb may serve as an effective thrust generator during aquatic locomotion. However, the hindlimb has previously been viewed as the dominant propulsive organ in swimming freshwater turtles. To evaluate the potential role of the forelimb in thrust production during swimming in freshwater turtles, we compared the forelimb morphology and three-dimensional forelimb kinematics of a highly aquatic trionychid turtle, the spiny softshell Apalone spinifera, and a morphologically generalized emydid turtle, the red-eared slider Trachemys scripta. Spiny softshells possess nearly twice as much forelimb surface area as sliders for generating drag-based thrust. In addition, although both species use drag-based propulsion, several aspects of forelimb kinematics differ significantly between these species. During the thrust phase of the forelimb cycle, spiny softshells hold the elbow and wrist joints significantly straighter than sliders, thereby further increasing the surface area of the limb that can move water posteriorly and increasing the velocity of the distal portion of the forelimb. These aspects of swimming kinematics in softshells should increase forelimb thrust production and suggest that the forelimbs make more substantial contributions to forward thrust in softshell turtles than in sliders. Spiny softshells also restrict forelimb movements to a much narrower dorsoventral and anteroposterior range than sliders throughout the stroke, thereby helping to minimize limb movements potentially extraneous to forward thrust production. These comparisons demonstrate considerable diversity in the forelimb kinematics of turtles that swim using rowing motions of the limbs and suggest that the evolution of turtle forelimb mechanics produced a variety of contrasting solutions for aquatic specialization.
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Yan, Zhengli, Huimiao Wei, Chuanlu Ren, Shishan Yuan, Hu Fu, Yuan Lv, Yongfei Zhu, and Tianbao Zhang. "Gene expression of Hsps in normal and abnormal embryonic development of mouse hindlimbs." Human & Experimental Toxicology 34, no. 6 (October 28, 2014): 563–74. http://dx.doi.org/10.1177/0960327114555927.
Full textAbstract:
Heat shock proteins (Hsps), which have important biological functions, are a class of highly conserved genetic molecules with the capacity of protecting and promoting cells to repair themselves from damage caused by various stimuli. Our previous studies found that Hsp25, HspB2, HspB3, HspB7, Hsp20, HspB9, HspB10, and Hsp40 may be related to all-trans retinoic acid (atRA)-induced phocomelic and other abnormalities, while HspA12B, HspA14, Trap1, and Hsp105 may be forelimb development-related genes; Grp78 may play an important role in forelimb development. In this study, the embryonic phocomelic, oligodactylic model of both forelimbs and hindlimbs was developed by atRA administered per os to the pregnant mice on gestational day 11, and the expression of 36 members of Hsps family in normal and abnormal development of embryonic hindlimbs was measured by real-time fluorescent quantitative polymerase chain reaction (qRT-PCR). It is found that HspA1L, Hsp22, Hsp10, Hsp60, Hsp47, HspB2, HspB10, HspA12A, Apg1, HspB4, Grp78, and HspB9 probably performs a major function in limb development, and HspA13, Grp94 and Hsp110 may be hindlimb development-related genes.
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Gondolfe, Mikaela, and Mark Garneau. "Correction of Carpal Valgus and Flexural Deformity with z-Tenotomy and Anastomosis Procedure in a Dog." VCOT Open 03, no. 01 (January 2020): e28-e32. http://dx.doi.org/10.1055/s-0040-1710069.
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AbstractThis study aimed to describe a staged bilateral z-tenotomy and anastomosis procedure of flexor carpi ulnaris and superficial digital flexor tendons for the correction of carpal valgus and flexural deformity in a 1-year-old male-neutered Akita dog. Bilateral carpal valgus and flexural deformity were observed with palpably taut flexor carpi ulnaris tendons. The dog had a mild, weight-bearing bilateral forelimb lameness with the left forelimb more severely affected. Both forelimbs were treated with staged z-tenotomy and anastomosis procedure of both flexor carpi ulnaris and superficial digital flexor tendons. Successful tendon lengthening and correction of carpal valgus were achieved via z-tenotomy and anastomosis of affected tendons. No complications were observed. An 18-month follow-up revealed no evidence of lameness or carpal valgus. Though tendon injuries commonly occur in small animal patients, there is a shortage of reported cases, especially involving musculotendinous contractures. There are even fewer reports of successful tenotomy procedures. This case report supports successful outcome of the z-tenotomy procedure in a canine patient.
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Alstermark, Bror, and Jun Ogawa. "In Vivo Recordings of Bulbospinal Excitation in Adult Mouse Forelimb Motoneurons." Journal of Neurophysiology 92, no. 3 (September 2004): 1958–62. http://dx.doi.org/10.1152/jn.00092.2004.
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Here we report on pyramidal and reticulospinal excitation in forelimb motoneurons in the adult mouse using intracellular recordings in vivo. The results have been obtained in BALB/C mice, which were anesthetized with midazolam fentanyl/fluanison. In contrast to the rat, only weak and infrequent pyramidal excitation could be evoked with a minimal trisynaptic linkage. Disynaptic reticulospinal excitation could always be evoked, as well as monosynaptic excitation from the medial longitudinal fasciculus. The results suggest that the reticulospinal pathway in the mouse is important in voluntary motor control of the forelimbs and that the role of the corticospinal tract might be different in mouse compared with rat. Our study provides an opening for studying the effect of genetic manipulation on specified descending systems in the mouse in vivo.
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Welch, J. M., C. M. Weaver, and C. H. Turner. "Adaptations to free-fall impact are different in the shafts and bone ends of rat forelimbs." Journal of Applied Physiology 97, no. 5 (November 2004): 1859–65. http://dx.doi.org/10.1152/japplphysiol.00438.2004.
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Impact exercise can have beneficial effects on the growing skeleton. To understand what changes it promotes in the shafts and ends of weight-bearing bones, we measured the effects of impact from repetitive free falls in growing rats. Fischer 344 female rats, 6.5 wk old, were assigned to one of three groups ( n = 10 each). Controls were not dropped, whereas those subjected to impact were dropped from 30 or 60 cm. Rats in both free-fall groups were dropped 10 times per day for 8 wk. Leg bones were mechanically tested, and their cross-sectional area (CSA), cross-sectional moments of inertia, and volumetric bone mineral density (BMD) were measured by peripheral quantitative computed tomography. In the shafts of the forelimbs, but not the hindlimbs, free-fall impact resulted in greater ultimate breaking force, minimum and maximum second moments of area, and CSA but not BMD. In the bone ends of the forelimb and tibial bones, trabecular BMD increased but CSA did not. Landing from 30 and 60 cm produced peak impact forces of 12.0 and 16.7 times the standing forefoot weight for each front leg and of 4.5 and 7.7 times the standing hind foot weight for each hind foot. Overall, free-fall impact affected the forelimbs by increasing trabecular bone density in the bone ends and improving the strength at the shaft as a result of geometric improvements. These results indicate that adaptation to impact may occur by different mechanisms in bone end and shaft regions.
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Sampaio, Breno Fernandes Barreto, Carmem Estefânia Serra Neto Zúccari, Monica Yurie Machado Shiroma, Beatriz Ramos Bertozzo, Ellen Cristina Rivas Leonel, Ricardo da Silva Surjus, Monique Maitê Malho Gomes, and Eliane Vianna da Costa e Silva. "Biometric hoof evaluation of athletic horses of show jumping, barrel, long rope and polo modalities." Revista Brasileira de Saúde e Produção Animal 14, no. 3 (September 2013): 448–59. http://dx.doi.org/10.1590/s1519-99402013000300017.
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This study aimed to evaluate, through biometry, the forelimb hoof of horses participating in show jumping, barrel, long rope and polo competitions. Thirty subjects were assessed in relation to each competition (total of 120 animals). The linear measurements (cm) included the dorsal length of the toe; medial and lateral lengths of the quarter; medial and lateral heights of the quarter; lateral and medial lengths of the heel; medial and lateral heights of the heel; hoof length; hoof width; frog length; and frog width. The following angles (°) were measured: toe angle, pastern angle, heel angle and shoulder palette. The length of the horseshoe, coronet circumference and body weight were also assessed. With the use of hoof biometric evaluation was possible to identify the imbalances of forelimb in athletic horses and the most common were broken-backward hoof angle, with 96.7% of the animals showing this in the right forelimb (RFL) and 95.8% in the left forelimb (LFL); and contracted heels, with 95.0% in the RFL and 87.6% in the LFL. The competition type in which greatest numbers of hoof balance abnormalities were shown was the long rope, followed by the barrel. There were high frequencies of medial/lateral imbalance in all the sports. We conclude that animals used in functional tests have a high incidence of hoof balance abnormalities in the forelimbs.