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Adaptive remodelling of the distal thoracic limb bones of a canine athlete
S80
Abstracts / Comparative Biochemistry and Physiology, Part A 150 (2008) S74–S92
A3.22 Morphological adaptations for jumping in the gibbon hind limb A. Channon, M. Gunther, E. Vereecke (University of Liverpool) Although gibbons are mainly known for being excellent brachiators, they are also highly skilled at jumping and are able to leap for distances of over 10 m in order to escape predation or confrontation. To date, very little is known about the jumping biomechanics and morphological adaptations for jumping in these primates. We undertook detailed dissections of the hind limbs of twelve unfixed gibbon cadavers belonging to four different species Hylobates lar (4), Hylobates moloch (2), Hylobates pileatus- (2) and Symphalangus syndactylus (4). Anatomical data collected included muscle and tendon mass and length, muscle fascicle length, and pennation angle. This data was used to calculate various parameters, such as PCSA and tendon CSA, which in turn were used to estimate properties of the muscles including maximum isometric force and muscle power, In addition, during dissection, an electro-goniometer and linear displacement sensor were used to collect muscle moment arm data using the tendon travel technique. The dissection data suggest that the large quadriceps femoris and triceps surae are adapted for high force production. We hypothesise that these muscles store energy in their large associated tendons for mechanical gain. We relate muscle architecture and moment arm data to the locomotory behaviour of the gibbon, with particular reference to jumping. We also present a comparative analysis between all three species of gibbon.
Greyhounds race anti-clockwise around relatively tight oval tracks. This is believed to impose asymmetric stresses on the distal limbs, leading to adaptive remodelling and characteristic fractures of certain bones. During remodelling, bone can be weaker and more susceptible to fracture if subjected to repeated stress. Bone mineral density (BMD) measurements are used to assess rates of adaptive remodeling. A better understanding of the remodelling process is needed to inform greyhound racing and training practices; particularly the frequency an individual dog is raced. We studied evidence for asymmetric remodelling by comparing BMD of left and right distal thoracic limb bones of greyhounds of known racing history. Thoracic limbs were collected from racing greyhounds, euthanatized following severe injury. Total BMD of the entire carpus and metacarpus, and then isolated carpal and metacarpal bones was determined using dual-energy X-ray absorptiometry (DXA). There were no significant left-to-right differences seen in total BMD of the entire carpus and metacarpus regions. However, total BMD of the right third and left forth carpal bones was significantly higher compared to the contra-lateral bones. BMD was also significantly higher in the right first, second and third, and the left fourth and fifth metacarpals. This increased BMD in the carpal and metacarpal bones on the rail side (inside of the bend) of each foot is evidence of asymmetric remodelling, presumably in response to the asymmetric distribution of forces that occur during racing. Our future studies will focus on relating racing history to BMD and the mechanical consequences of these changes. doi:10.1016/j.cbpa.2008.04.131
doi:10.1016/j.cbpa.2008.04.129
A3.23 Size and shape in the carnivore scapula E. Gálvez-López, A. Casinos (University of Barcelona) The scapula is one of the morphologically more variable bones in the carnivore postcranial skeleton, but the causes of such variation are unclear. The aim of this study is to assess to which factors the shape variation in the carnivore scapula is related, since the order Carnivora presents not only a high variability in scapular morphology, but also in body size, locomotor behaviour, and habitat. Shape differences were computed using geometric morphometric techniques on a sample of 74 specimens belonging to 27 species. Results show that morphological variation in the carnivore scapula is related both to phylogeny and locomotor behaviour, but not to habitat. The first and second relative warps clearly separated, respectively, seals and sea lions in one group, and bears in another, defining a particular scapular morphology for each group. On the contrary no particular scapular morphology could be associated to the different locomotor behaviours of the carnivore species studied. doi:10.1016/j.cbpa.2008.04.130
A3.24 Adaptive remodelling of the distal thoracic limb bones of a canine athlete C. Hercock, I. Young, J. Innes, D. Hodson (University of Liverpool)
A3.25 Learning to walk modifies the whole locomotor skeleton: Bipedalism and impact of gravity in humans C. Tardieu (C.N.R.S.); J. Hecquet (C.N.R.S.); C. Boulay (Hopital La Timone); G. Duval-beaupere (I.N.S.E.R.M.); J. Legaye (Clinique Universitaire, Louvain) Loading of the skeleton and learning to walk entail drastic changes of the whole locomotor skeleton vertebral column, pelvis and lowerlimbs. We present an overview of the changes affecting this complex interarticular system, pointing out impact of growth and gravity. We looked for pelvic parameters establishing functional links with vertebral column on one hand and with lower limbs on the other hand. A major acquisition during learning to walk is the sagittal balance of the trunk above the lower limbs. We demonstrated the role of the pelvis in this balance by discovering a new sagittal pelvic parameter the “angle of sacral incidence” (mean: 54°; extreme: 35°– 75°). Adequate correlations between the degree of incidence and of vertebral curves ensure an economical balance. We present the lower values of this parameter in occasionally biped primates and its significant increase in young Japanese macaques trained for bipedalism. During the transition from the abducted position of the lower limbs in newborns to their adducted position in adult, numerous three-dimensional modifications of the femoral axes occur. We hypothesized that the three-dimensional orientation of the acetabula plays a role in these changes. We developed a software package, “DE-VISU”, devoted to the pelvis and applied it to 70 adult and newborn human pelves, revealing that acetabular orientation changes during postnatal growth. These changes will strongly interact with those of the directional axes of the lower limbs.
Abstracts / Comparative Biochemistry and Physiology, Part A 150 (2008) S74–S92
A3.22 Morphological adaptations for jumping in the gibbon hind limb A. Channon, M. Gunther, E. Vereecke (University of Liverpool) Although gibbons are mainly known for being excellent brachiators, they are also highly skilled at jumping and are able to leap for distances of over 10 m in order to escape predation or confrontation. To date, very little is known about the jumping biomechanics and morphological adaptations for jumping in these primates. We undertook detailed dissections of the hind limbs of twelve unfixed gibbon cadavers belonging to four different species Hylobates lar (4), Hylobates moloch (2), Hylobates pileatus- (2) and Symphalangus syndactylus (4). Anatomical data collected included muscle and tendon mass and length, muscle fascicle length, and pennation angle. This data was used to calculate various parameters, such as PCSA and tendon CSA, which in turn were used to estimate properties of the muscles including maximum isometric force and muscle power, In addition, during dissection, an electro-goniometer and linear displacement sensor were used to collect muscle moment arm data using the tendon travel technique. The dissection data suggest that the large quadriceps femoris and triceps surae are adapted for high force production. We hypothesise that these muscles store energy in their large associated tendons for mechanical gain. We relate muscle architecture and moment arm data to the locomotory behaviour of the gibbon, with particular reference to jumping. We also present a comparative analysis between all three species of gibbon.
Greyhounds race anti-clockwise around relatively tight oval tracks. This is believed to impose asymmetric stresses on the distal limbs, leading to adaptive remodelling and characteristic fractures of certain bones. During remodelling, bone can be weaker and more susceptible to fracture if subjected to repeated stress. Bone mineral density (BMD) measurements are used to assess rates of adaptive remodeling. A better understanding of the remodelling process is needed to inform greyhound racing and training practices; particularly the frequency an individual dog is raced. We studied evidence for asymmetric remodelling by comparing BMD of left and right distal thoracic limb bones of greyhounds of known racing history. Thoracic limbs were collected from racing greyhounds, euthanatized following severe injury. Total BMD of the entire carpus and metacarpus, and then isolated carpal and metacarpal bones was determined using dual-energy X-ray absorptiometry (DXA). There were no significant left-to-right differences seen in total BMD of the entire carpus and metacarpus regions. However, total BMD of the right third and left forth carpal bones was significantly higher compared to the contra-lateral bones. BMD was also significantly higher in the right first, second and third, and the left fourth and fifth metacarpals. This increased BMD in the carpal and metacarpal bones on the rail side (inside of the bend) of each foot is evidence of asymmetric remodelling, presumably in response to the asymmetric distribution of forces that occur during racing. Our future studies will focus on relating racing history to BMD and the mechanical consequences of these changes. doi:10.1016/j.cbpa.2008.04.131
doi:10.1016/j.cbpa.2008.04.129
A3.23 Size and shape in the carnivore scapula E. Gálvez-López, A. Casinos (University of Barcelona) The scapula is one of the morphologically more variable bones in the carnivore postcranial skeleton, but the causes of such variation are unclear. The aim of this study is to assess to which factors the shape variation in the carnivore scapula is related, since the order Carnivora presents not only a high variability in scapular morphology, but also in body size, locomotor behaviour, and habitat. Shape differences were computed using geometric morphometric techniques on a sample of 74 specimens belonging to 27 species. Results show that morphological variation in the carnivore scapula is related both to phylogeny and locomotor behaviour, but not to habitat. The first and second relative warps clearly separated, respectively, seals and sea lions in one group, and bears in another, defining a particular scapular morphology for each group. On the contrary no particular scapular morphology could be associated to the different locomotor behaviours of the carnivore species studied. doi:10.1016/j.cbpa.2008.04.130
A3.24 Adaptive remodelling of the distal thoracic limb bones of a canine athlete C. Hercock, I. Young, J. Innes, D. Hodson (University of Liverpool)
A3.25 Learning to walk modifies the whole locomotor skeleton: Bipedalism and impact of gravity in humans C. Tardieu (C.N.R.S.); J. Hecquet (C.N.R.S.); C. Boulay (Hopital La Timone); G. Duval-beaupere (I.N.S.E.R.M.); J. Legaye (Clinique Universitaire, Louvain) Loading of the skeleton and learning to walk entail drastic changes of the whole locomotor skeleton vertebral column, pelvis and lowerlimbs. We present an overview of the changes affecting this complex interarticular system, pointing out impact of growth and gravity. We looked for pelvic parameters establishing functional links with vertebral column on one hand and with lower limbs on the other hand. A major acquisition during learning to walk is the sagittal balance of the trunk above the lower limbs. We demonstrated the role of the pelvis in this balance by discovering a new sagittal pelvic parameter the “angle of sacral incidence” (mean: 54°; extreme: 35°– 75°). Adequate correlations between the degree of incidence and of vertebral curves ensure an economical balance. We present the lower values of this parameter in occasionally biped primates and its significant increase in young Japanese macaques trained for bipedalism. During the transition from the abducted position of the lower limbs in newborns to their adducted position in adult, numerous three-dimensional modifications of the femoral axes occur. We hypothesized that the three-dimensional orientation of the acetabula plays a role in these changes. We developed a software package, “DE-VISU”, devoted to the pelvis and applied it to 70 adult and newborn human pelves, revealing that acetabular orientation changes during postnatal growth. These changes will strongly interact with those of the directional axes of the lower limbs.