Musculoskeletal Components Research Articles

The scaling of tongue projection in the veiled chameleon, Chamaeleo calyptratus

Within a year of hatching, chameleons can grow by up to two orders of magnitude in body mass. Rapid growth of the feeding mechanism means that bones, muscles, and movements change as chameleons grow while needing to maintain function. A previous morphological study showed that the musculoskeletal components of the feeding apparatus grow with negative allometry relative to snout–vent length (SVL) in chameleons. Here, we investigate the scaling of prey capture kinematics and muscle physiological cross-sectional area in the veiled chameleon, Chamaeleo calyptratus. The chameleons used in this study varied in size from approximately 3 to 18cm SVL (1–200g). Feeding sequences of 12 chameleons of different sizes were filmed and the timing of movements and the displacements and velocities of the jaws, tongue, and the hyolingual apparatus were quantified. Our results show that most muscle cross-sectional areas as well as tongue and hyoid mass scaled with isometry relative to mandible length, yet with negative allometry relative to SVL. Durations of movement also scaled with negative allometry relative to SVL and mandible length. Distances and angles generally scaled as predicted under geometric similarity (slopes of 1 and 0, respectively), while velocities generally scaled with slopes greater than 0 relative to SVL and mandible length. These data indicate that the velocity of jaw and tongue movements is generally greater in adults compared to juveniles. The discrepancy between the scaling of cross-sectional areas versus movements suggests changes in the energy storage and release mechanisms implicated in tongue projection.

Condición física y riesgo cardiovascular futuro en niños y adolescentes argentinos: una introducción de la batería ALPHA

A high level of physical fitness is associated with cardiovascular health in children and adolescents. At present, there is no systematic implementation of a test battery to assess physical fitness at schools in Argentina. The main objective of this study was to implement the ALPHA test battery to determine the physical fitness of a sample made up of Argentine children and adolescents and to establish the proportion of subjects whose aerobic capacity is indicative of future cardiovascular risk. A sample of 1867 participants (967 girls) aged 6 to 19.5 years old assessed using the ALPHA test battery. Four components of physical fitness were measured: 1) morphological component: height, body weight, and waist circumference; 2) musculoskeletal component: standing long jump test; 3) motor component: speed/agility test (4x10 m shuttle run); 4) cardiorespiratory component: course-navette 20 m, shuttle run test and estimation of maximal oxygen consumption. The 5th, 25th, 50th, 75th, and 95th percentiles were estimated for the main tests. The mean body mass index was 20.8 kg/m2, and 7.8% of participants were classified as obese. In ddition, male participants had a better performance in all physical fitness tests when compared to girls (p< 0.001). An aerobic capacity indicative of cardiovascular risk was observed in 31.6% of all participants. Argentine male children and adolescents included in the sample showed higher levels of physical fitness. Such differences increase with age. Approximately one every three participants had an aerobic capacity indicative of future cardiovascular risk.

Physical fitness and future cardiovascular risk in argentine children and adolescents: an introduction to the ALPHA test battery.

A high level of physical fitness is associated with cardiovascular health in children and adolescents. At present, there is no systematic implementation of a test battery to assess physical fitness at schools in Argentina. The main objective of this study was to implement the ALPHA test battery to determine the physical fitness of a sample made up of Argentine children and adolescents and to establish the proportion of subjects whose aerobic capacity is indicative of future cardiovascular risk. A sample of 1867 participants (967 girls) aged 6 to 19.5 years old assessed using the ALPHA test battery. Four components of physical fitness were measured: 1) morphological component: height, body weight, and waist circumference; 2) musculoskeletal component: standing long jump test; 3) motor component: speed/agility test (4x10 m shuttle run); 4) cardiorespiratory component: course-navette 20 m, shuttle run test and estimation of maximal oxygen consumption. The 5th, 25th, 50th, 75th, and 95th percentiles were estimated for the main tests. The mean body mass index was 20.8 kg/m2, and 7.8% of participants were classified as obese. In ddition, male participants had a better performance in all physical fitness tests when compared to girls (p< 0.001). An aerobic capacity indicative of cardiovascular risk was observed in 31.6% of all participants. Argentine male children and adolescents included in the sample showed higher levels of physical fitness. Such differences increase with age. Approximately one every three participants had an aerobic capacity indicative of future cardiovascular risk.

The effect of hand-arm vibration syndrome on quality of life

It is important to determine how hand-arm vibration syndrome (HAVS), a common occupational condition, affects quality of life (QOL). To measure the physical (SF12-P) and mental (SF12-M) components of QOL in workers with HAVS, using the SF12 questionnaire, and to determine the effect of the vascular, sensorineural and musculoskeletal components of HAVS on QOL. Subjects were recruited consecutively from workers with HAVS attending an occupational medicine clinic. They were assessed to determine the Stockholm vascular and sensorineural scale stages as well as an upper extremity pain score, measured by the Borg scale, as an indication of musculoskeletal problems associated with the use of vibrating tools. The SF12-P and SF12-M were both compared with Canadian population normal values after adjusting for age and sex. Multiple linear regression was used to determine the effect of the various HAVS components on SF12-P and SF12-M as well as the effects of age and carpal tunnel syndrome. One hundred and forty-one subjects were recruited and 139 (99%) agreed to participate, including 134 men and 5 women. The SF12-P and SF12-M scores were significantly below the Canadian population mean values (P < 0.001), indicating lower QOL. In the multiple regression analysis, the predictor with the largest partial R (2) value for both the SF12-P and SF12-M was the upper extremity pain score. Both the physical and the mental QOL in workers with HAVS were below Canadian population normal values and subjects' upper extremity pain score had the greatest effect on their QOL.

Water‐selective excitation of short T2 species with binomial pulses

For imaging of fibrous musculoskeletal components, ultra-short echo time methods are often combined with fat suppression. Due to the increased chemical shift, spectral excitation of water might become a favorable option at ultra-high fields. Thus, this study aims to compare and explore short binomial excitation schemes for spectrally selective imaging of fibrous tissue components with short transverse relaxation time (T2 ). Water selective 1-1-binomial excitation is compared with nonselective imaging using a sub-millisecond spoiled gradient echo technique for in vivo imaging of fibrous tissue at 3T and 7T. Simulations indicate a maximum signal loss from binomial excitation of approximately 30% in the limit of very short T2 (0.1 ms), as compared to nonselective imaging; decreasing rapidly with increasing field strength and increasing T2 , e.g., to 19% at 3T and 10% at 7T for T2 of 1 ms. In agreement with simulations, a binomial phase close to 90° yielded minimum signal loss: approximately 6% at 3T and close to 0% at 7T for menisci, and for ligaments 9% and 13%, respectively. Overall, for imaging of short-lived T2 components, short 1-1 binomial excitation schemes prove to offer marginal signal loss especially at ultra-high fields with overall improved scanning efficiency.

A computational model of torque generation: neural, contractile, metabolic and musculoskeletal components.

The pathway of voluntary joint torque production includes motor neuron recruitment and rate-coding, sarcolemmal depolarization and calcium release by the sarcoplasmic reticulum, force generation by motor proteins within skeletal muscle, and force transmission by tendon across the joint. The direct source of energetic support for this process is ATP hydrolysis. It is possible to examine portions of this physiologic pathway using various in vivo and in vitro techniques, but an integrated view of the multiple processes that ultimately impact joint torque remains elusive. To address this gap, we present a comprehensive computational model of the combined neuromuscular and musculoskeletal systems that includes novel components related to intracellular bioenergetics function. Components representing excitatory drive, muscle activation, force generation, metabolic perturbations, and torque production during voluntary human ankle dorsiflexion were constructed, using a combination of experimentally-derived data and literature values. Simulation results were validated by comparison with torque and metabolic data obtained in vivo. The model successfully predicted peak and submaximal voluntary and electrically-elicited torque output, and accurately simulated the metabolic perturbations associated with voluntary contractions. This novel, comprehensive model could be used to better understand impact of global effectors such as age and disease on various components of the neuromuscular system, and ultimately, voluntary torque output.

A Rare Case of Craniofacial Morphology with Absent Face and Neck Structures, with Its Review

The development of the head and the face requires an intimate interaction between two mesenchymal populations, a paraxial mesoderm and neural crest cells for the morphogenesis of the musculoskeletal components of the calvaria, the face and the branchial regions. The disruptions in these interactions can cause foetal fatalities or congenital craniofacial anomalies. We are describing a rarest case with a craniofacial malformation, who was born with complete absence of the facial skeleton and the neck structures, a set of well developed ears in their normal locations and eyelids at the junction between the head and the thorax.

THE EVOLUTION OF LOCOMOTOR RHYTHMICITY IN TETRAPODS

Differences in rhythmicity (relative variance in cycle period) among mammal, fish, and lizard feeding systems have been hypothesized to be associated with differences in their sensorimotor control systems. We tested this hypothesis by examining whether the locomotion of tachymetabolic tetrapods (birds and mammals) is more rhythmic than that of bradymetabolic tetrapods (lizards, alligators, turtles, salamanders). Species averages of intraindividual coefficients of variation in cycle period were compared while controlling for gait and substrate. Variance in locomotor cycle periods is significantly lower in tachymetabolic than in bradymetabolic animals for datasets that include treadmill locomotion, non-treadmill locomotion, or both. When phylogenetic relationships are taken into account the pooled analyses remain significant, whereas the non-treadmill and the treadmill analyses become nonsignificant. The co-occurrence of relatively high rhythmicity in both feeding and locomotor systems of tachymetabolic tetrapods suggests that the anatomical substrate of rhythmicity is in the motor control system, not in the musculoskeletal components.

High‐resolution Fourier‐encoded sub‐millisecond echo time musculoskeletal imaging at 3 Tesla and 7 Tesla

The feasibility of imaging musculoskeletal fibrous tissue components, such as menisci, ligaments, and tendons, with a conventional spoiled gradient echo technique is explored in vivo at 3 T and 7 T. To this end, the echo time (TE1 ) of a conventional Fourier-encoded multicontrast three-dimensional SGPR sequence is minimized by using nonselective excitation pulses, highly asymmetric readouts, and a variable TE1 along the phase and slice encoding direction. In addition, a fully sampled second echo image (with TE2 >> TE1 ) can be used to highlight components with short transverse relaxation times in a difference image with positive contrast. Fourier-encoded spoiled gradient echo sequences are able to provide sub-millisecond TE1 of about 800 μs for typical in-plane resolutions of about 0.5 x 0.5 mm(2) . As a result, high-resolution positive contrast images of fibrous tissues can be generated within clinically feasible scan-time of about 2-7 minutes. After optimization, Fourier-encoded spoiled gradient echo provides a highly robust and flexible imaging technique for high-resolution positive contrast imaging of fibrous tissue that can readily be used in the clinical routine.

Composición corporal y somatotipo de nadadores adolescentes federados

IntroductionThe swimmer is a high level athlete, with long limbs, and whose musculoskeletal components are important in sporting success. However, the fat component is paradoxical because of its relationship with the buoyancy and displacement of the body in the water. The aim of this study is to describe the anthropometric profile of adolescent competition swimmers. Material and methodsA total of 17 adolescent swimmers were evaluated, 10 boys (13.2±1.32 years) and 7 girls (15±1.83 years). A qualified anthropometrist took anthropometric measures according to the protocol of the Society for the Advancement of Kinanthropometry (ISAK), with approved materials according to the methodology of Marfell-Jones et al, 2003. Body composition was calculated according to the consensus of Kinanthropometry and somatotype with Heath-Carter's method. ResultsOf all the variables studied (weight, height, folds, circumferences, diameters and lengths), significant differences were found (P<.05) between the sexes in height, arm span, skinfolds (triceps, subscapular, crestailiaca, ileo-spinal, abdominal, thigh, leg, sum of skinfolds), biacromial-bi-iliac index, bone body mass, muscle and fat, ectomorphy, and endomorphy. ConclusionsThere are significant anthropometric differences between genders in adolescent swimmers (P<.05). Such differences, resulting in the development of both sexes, might be highly related to athletic performance of young athletes.

Scaling of the ballistic tongue apparatus in chameleons

Body dimensions of organisms can have a profound impact on their functional and structural properties. We examined the morphological proportions of the feeding apparatus of 105 chameleon specimens representing 23 species in seven genera, spanning a 1,000-fold range in body mass to test whether the feeding apparatus conforms to the null hypotheses of geometric similarity that is based on the prevalence of geometric similarity in other ectothermic vertebrates. We used a phylogenetically corrected regression analysis based on a composite phylogenetic hypothesis to determine the interspecific scaling patterns of the feeding apparatus. We also determined the intraspecific (ontogenetic) scaling patterns for the feeding apparatus in three species. We found that both intraspecifically and interspecifically, the musculoskeletal components of the feeding apparatus scale isometrically among themselves, independent of body length. The feeding apparatus is thus of conserved proportions regardless of overall body length. In contrast, we found that the tongue apparatus as a whole and its musculoskeletal components scale with negative allometry with respect to snout-vent length--smaller individuals have a proportionately larger feeding apparatus than larger individuals, both within and among species. Finally, the tongue apparatus as a whole scales with negative allometry with respect to body mass through ontogeny, but with isometry interspecifically. We suggest that the observed allometry may be maintained by natural selection because an enlarged feeding apparatus at small body size may maximize projection distance and the size of prey that smaller animals with higher mass-specific metabolic rates can capture.

Musculoskeletal US: Taking the Management of Psoriatic Arthritis to a New Horizon

Understanding the disease pathogenesis and tissues structure changes have a positive impact on its management. In psoriatic patients suffering from arthritis, there is a variable spectrum of pathologic changes that include joint and tendon inflammation, new bone formation as well as severe osteolysis. This led to the proposition of the term “psoriatic disease” to encompass the involvement at different tissue and organ levels. The continuous technological advances in the field of musculoskeletal ultrasound allowed the detailed study of morpho-structural changes of the joints, entheses as well as skin and nails. Power Doppler Ultrasonography allowed the sensitive detection of blood flow even in small vessels of superficial tissues which facilitated the assessment of the inflammatory process activity and response to therapy. The ease of access, ability to scan repeatedly, as well as utility of ultrasound in the assessment of different musculoskeletal components offer major advantages over MRI and nuclear medicine in standard clinical practice. This article will review how US imaging has the potential to transform our understanding of psoriasis, and the potential role of musculoskeletal US, as a sensitive imaging modality, to assess the inflammatory process, disease activity as well as outcomes of therapy in patients with psoriatic arthritis. Keywords: Psoriasis, psoriatic arthritis, US, patient reported outcome measures, inflammatory arthritis

Computer‐controlled, MR‐compatible foot‐pedal device to study dynamics of the muscle tendon complex under isometric, concentric, and eccentric contractions

To design a computer-controlled, magnetic resonance (MR)-compatible foot pedal device that allows in vivo mapping of changes in morphology and in strain of different musculoskeletal components of the lower leg under passive, isometric, concentric, and eccentric contractions. A programmable servomotor in the control room pumped hydraulic fluid to rotate a foot-pedal inside the magnet. To validate the performance of the device, six subjects were imaged with gated velocity-encoded phase-contrast (VE-PC) imaging to investigate the dynamics of muscle and aponeurotic structures. Artifact-free VE-PC imaging clearly delineated different muscle compartments by differences in distribution of mechanical strains. High repeatability of contraction cycles allowed establishing that fascicles lengthened 6.1% more during passive compared with eccentric contractions. Aponeurosis separation during passive (range between three locations: -2.6≈1.3 mm) and active (range: -2.4≈1.6 mm) contractions were similar but significantly different from concentric (range: -0.9≈3.3 mm), with proximal and distal regions showing mostly negative values for the first two modes, but positive for the last. The device was sufficiently robust and artifact-free to accurately assess, using VE-PC imaging, physiologically important structure and dynamics of the musculotendon complex.

Distinguishing Inflammatory from Noninflammatory Arthritis, Enthesitis, and Dactylitis in Psoriatic Arthritis: A Report from the GRAPPA 2010 Annual Meeting: Table 1.

The most widely applied criteria for classifying psoriatic arthritis (PsA) are the CASPAR (ClASsification of Psoriatic ARthritis) criteria. A patient who fulfills the CASPAR criteria must have evidence of inflammatory arthritis, enthesitis, or spondylitis, and may have an inflammatory musculoskeletal component, dactylitis. Although the criteria were developed by rheumatologists, not all patients with PsA are seen by rheumatologists. Thus, it is important for clinicians such as dermatologists, primary care providers, physiatrists, and orthopedists, and patients themselves, to be able to recognize the presence of inflammatory musculoskeletal disease and distinguish it from degenerative or traumatic musculoskeletal disease. At their 2010 annual meeting, members of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) discussed the steps they are taking to define the key variables that must be present to distinguish inflammatory arthritis, enthesitis, and dactylitis from degenerative, traumatic, mechanical, or infectious forms of these conditions.

Effects of body elasticity on stability of underwater locomotion

AbstractWe examine the stability of the ‘coast’ motion of fish, that is to say, the motion of a neutrally buoyant fish at constant speed in a straight line. The forces and moments acting on the fish body are thus perfectly balanced. The fish motion is said to be unstable if a perturbation in the conditions surrounding the fish results in forces and moments that tend to increase the perturbation, and it is stable if these emerging forces tend to reduce the perturbation and return the fish to its original state. Stability may be achieved actively or passively. Active stabilization requires neurological control that activates musculo-skeletal components to compensate for the external perturbations acting against stability. Passive stabilization on the other hand requires no energy input by the fish and is dependent upon the fish morphology, i.e. geometry and elastic properties. In this paper, we use a deformable body consisting of an articulated body equipped with torsional springs at its hinge joints and submerged in an unbounded perfect fluid as a simple model to study passive stability as a function of the body geometry and spring stiffness. We show that for given body dimensions, the spring elasticity, when properly chosen, leads to passive stabilization of the (otherwise unstable) coast motion.

Identification of Neural Feedback for Upright Stance in Humans: Stabilization rather than Sway Minimization

A fundamental issue in motor control is how to determine the task goals for a given behavior. Here, we address this question by separately identifying the musculoskeletal and feedback components of the human postural control loop. Eighteen subjects were perturbed by two mechanical perturbations (gentle pulling from behind at waist and shoulder levels) and one sensory perturbation (movement of a virtual visual scene). Body kinematics was described by the leg and trunk segment angles in the sagittal plane. Muscle activations were described by ankle and hip EMG signals, with each EMG signal computed as a weighted sum of rectified EMG signals from multiple muscles at the given joint. The mechanical perturbations were used to identify feedback, defined as the mapping from the two segment angles to the two EMG signals. The sensory perturbation was used to estimate parameters in a mechanistic model of the plant, defined as the mapping from the two EMG signals to the two segment angles. Using the plant model and optimal control theory, we compared identified feedback to optimal feedback for a range of cost functions. Identified feedback was similar to feedback that stabilizes upright stance with near-minimum muscle activation, but was not consistent with feedback that substantially increases muscle activation to reduce movements of the body's center of mass or center of pressure. The results suggest that the common assumption of reducing sway may not apply to musculoskeletal systems that are inherently unstable.

Inter-rater reliability of a musculoskeletal screen as administered to female professional contemporary dancers

The purpose of this study is to determine the inter-rater reliability of commonly used musculoskeletal screening components in a population of contemporary professional dancers. Study participants were 30 women from six contemporary dance companies between the ages of 18 and 32, with a mean age of 24, and Body Mass Index of 22.4. 101 items were assessed in the categories of Static Posture, the Beighton 9-Point Hypermobility Test, Flexibility, Strength, and Dynamic Posture, based upon the Pilot 2006 Dance USA Annual Post-Hire Health Screen for Professional Dancers. Testing was non-ordered, using 2 of the 4 available testers, with variable assignment of the lead tester. High percent agreement was found for the subcategories of hallux valgus, pelvic tilt, and forefoot alignment, flexor hallucis, iliopsoas, hip internal rotation flexed, external rotation extended, and soleus extensibility, composite Beighton, and for most measures within the dynamic posture category. Low to moderate percent agreement was found in the strength tests. Although this study demonstrated moderate to high percent agreement between raters, further test refinement is needed to improve the reliability of the measurement components.

Trunk strength and mobility changes in children with slow transit constipation

It appears that there are no published reports on childhood slow transit constipation (STC) that have considered the state of the musculoskeletal components of the trunk in these children. The present study aimed to determine whether children with STC have different trunk musculoskeletal characteristics that might be related to their defecation difficulties, compared to controls. With the aid of computer-analyzed photographs and clinical testing, 41 children with STC and 41 age-matched controls were examined for Marfanoid features, sitting posture, spinal joint mobility and trunk muscle strength. The latter was assessed by measuring maximum voluntary abdominal bulging and retraction in sitting, and active trunk extension in prone-lying. Levels of general exercise and sedentary activities were evaluated by questionnaire. STC subjects were more slumped in relaxed sitting (P < or = 0.001), less able to bulge (P < or = 0.03) and less able to actively extend the trunk (P = 0.02) compared to controls. All subjects sat more erect during abdominal bulging (P < or = 0.03). The results show that STC children have reduced trunk control and posture, which indicates that clinicians should include training of trunk muscles and correction of sitting posture. There was no evidence that children with STC exercised less than the controls.

Ultrasonographic and Physical Examination to Investigate the Cause of Painful Hemiplegic Shoulder

Objective: To investigate the musculoskeletal cause of hemiplegic shoulder pain using ultrasonographic evaluation of hemiplegic shoulder Method: Thirty-six hemiplegic patients admitted to rehabilitation department were enrolled. Ultrasonographic investigation of shoulder and physical examinations including range of motion (ROM), muscle power, spasticity and subluxation of shoulders were performed. Results: Eighteen (55.6%) patients reported pain in hemiplegic shoulder. The abnormal sonographic findings, ROM, muscle power, spasticity, and subluxation of hemiplegic shoulder were not significantly different between subjects with painful hemiplegic shoulder and those without. The presence of ultrasonographic abnormality combined with focal tenderness, however, was significantly related with the painfulness of hemiplegic shoulder (p-value = 0.03). Conclusion: These results suggest that ultrasonographic evaluation is useful to investigate the musculoskeletal component of painful hemiplegic shoulder, when collaborated with physical examination of focal tenderness. (Brain & NeuroRehabilitation 2009; 2: 140-145)

Introduction to Diagnostic Musculoskeletal Ultrasound

This is the second of two articles focusing on ultrasound examination of musculoskeletal components of the upper and lower limbs. Treatment of musculoskeletal injuries is based on establishing an accurate diagnosis. No one would dispute that a good history and physical examination by a competent clinician can help achieve that in the majority of cases. However, musculoskeletal imaging is also an essential adjunct in the work-up of many musculoskeletal disorders. This article describes the ultrasound examination of the lower limb in terms of anatomic structure. Normal and pathologic ultrasound features of these structures, including muscles, tendons, ligaments, bursae, and other soft tissues of the lower limb, will be described by reviewing several representative pathologies commonly seen in musculoskeletal medicine.