Large Range Of Motion Research Articles

Natural Course and Prognostic Factors in Patients With Mild Cervical Spondylotic Myelopathy With Increased Signal Intensity on T2-Weighted Magnetic Resonance Imaging

A retrospective comparative study. To investigate natural course and prognostic factors in patients with mild forms of cervical spondylotic myelopathy (CSM), focusing on intramedullary increased signal intensity (ISI) on T2-weighted magnetic resonance imaging. Long-term natural course of mild forms of CSM, especially with ISI on magnetic resonance imaging, remains uncertain. Patients with CSM who visited our institution between 1992 and 2004 and did not undergo surgery at first visit were retrospectively reviewed. The inclusion criteria were as follows: (1) motor function Japanese Orthopedic Association scores of 3 or more in both upper and lower extremities and (2) cervical spinal cord compression with ISI on T2-weighted magnetic resonance imaging. There were 45 patients, with a mean follow-up period of 78 months (range, 24-208). We investigated long-term natural history by setting the timing of conversion to surgery due to neurological deterioration as an end point. We further compared prognostic parameters between patients who converted to surgery and those who continued to be followed up nonsurgically. Sixteen patients gradually deteriorated and underwent decompression surgery, whereas 27 patients did not. Apart from these, 2 patients with acute spinal cord injury after minor trauma underwent surgery. Kaplan-Meier survival analysis revealed that 82% or 56% of patients did not require surgery 5 or 10 years after the initial treatment, respectively. As for prognostic factors, Cox proportional hazard analysis revealed that total cervical range of motion (hazard ratio: 3.25), segmental kyphosis in the maximum compression segment (hazard ratio: 4.51), and local slip (hazard ratio: 4.67) were statistically significant. Fifty-six percent of patients with clinically mild CSM with ISI had not deteriorated or undergone surgery at 10 years. Large range of motion, segmental kyphosis, and instability at the narrowest canal were considered to be adverse prognostic factors.

A multi-resolution approach for massively-parallel hardware-friendly optical flow estimation

This paper presents a novel hardware-friendly motion estimation for real-time applications such as robotics or autonomous navigation. Our approach is based on the well-known Lucas & Kanade local algorithm, whose main problem is the unreliability of its estimations for large-range displacements. This disadvantage is solved in the literature by adding the sequential multiscale-with-warping extension, although it dramatically increases the computational cost. Our choice is the implementation of a multiresolution scheme that avoids the warping computation and allows the estimation of large-range motion. This alternative allows the parallel computation of the scale-by-scale motion estimation which makes the whole computation lighter and significantly reduces the processing time compared with the multiscale-with-warping approach. Furthermore, this last fact also means reducing the hardware resource cost for its potential implementation in digital hardware devices such as GPUs, ASICs, or FPGAs. In the discussion, we analyze the speedup of the multiresolution approach compared to the multiscale-with-warping scheme. For an FPGA implementation, we obtain a reduction of latency between 40% and 50% and a resource reduction of 30%. The final solution copes with large-range motion estimations with a simplified architecture very well-suited for customized digital hardware datapath implementations as well as current multicore architectures.

Effect of take-off from prosthetic versus intact limb on transtibial amputee long jump technique

Increasing numbers of long jumpers with lower limb amputations choose to take off from their prosthetic limb. It is not yet known what difference in technique, if any, this requires, or which is more advantageous. To investigate kinematic differences in long jump technique in athletes with a unilateral transtibial ampution (TT) who take off from their prosthetic limb versus those who take off from their intact limb. Naturalistic, field-based, observational; independent group, nonparametric comparison. Two-dimensional sagittal plane kinematic analysis was performed on all athletes competing in the men's Paralympic TT long jump finals. Five athletes took off from their prosthetic limb (TO(prosth)) and five from their intact limb (TO(intact)). No differences were seen between the two groups in terms of jump distance, approach speed or vertical velocity at touch down. While in contact with the take-off board, the two groups gained a similar amount of vertical velocity. However, the TO(prosth) group appeared to conserve horizontal velocity by using the prosthesis as a 'springboard', minimizing the large hip and knee range of motion displayed by the TO(intact) group and athletes in previous studies. While differences in technique were observed, no difference was found for jump distance.

Analysis of annulus-shaped compliant pivot with series–parallel leaves

Annulus-shaped compliant pivot, formed by well-proportioned compliant modules between the outer ring and inner ring, can be employed in precision mechanical systems due to good performances. Especially for the multi-series leaves in one module, the annulus-shaped compliant pivot can fulfill a large displacement range without any axial drift in theory. In the design of the annulus-shaped compliant pivot, the load–displacement behavior and the stress analysis with analytical forms are important consideration. However, in the literature, there is few detailed work. In this article, a general annulus-shaped compliant pivot model formed by series–parallel leaves is first analytically established for the load–displacement behavior and the stress prediction. These calculations are based on accurate approximation of a beam flexure. Firstly, a loaded moment is decomposed into universal loads by combining the geometric compatibility condition. The stiffness accurate approximation is then analytically obtained, which provides a simple design strategy. Furthermore, the stresses in every leaf are obtained so that the annulus-shaped compliant pivot with large motion range can be actualized by stress checking. Lastly, the analytical model has been verified by commercial finite element analysis software ANSYS.

Detail-Preserving Controllable Deformation from Sparse Examples

Recent advances in laser scanning technology have made it possible to faithfully scan a real object with tiny geometric details, such as pores and wrinkles. However, a faithful digital model should not only capture static details of the real counterpart but also be able to reproduce the deformed versions of such details. In this paper, we develop a data-driven model that has two components; the first accommodates smooth large-scale deformations and the second captures high-resolution details. Large-scale deformations are based on a nonlinear mapping between sparse control points and bone transformations. A global mapping, however, would fail to synthesize realistic geometries from sparse examples, for highly deformable models with a large range of motion. The key is to train a collection of mappings defined over regions locally in both the geometry and the pose space. Deformable fine-scale details are generated from a second nonlinear mapping between the control points and per-vertex displacements. We apply our modeling scheme to scanned human hand models, scanned face models, face models reconstructed from multiview video sequences, and manually constructed dinosaur models. Experiments show that our deformation models, learned from extremely sparse training data, are effective and robust in synthesizing highly deformable models with rich fine features, for keyframe animation as well as performance-driven animation. We also compare our results with those obtained by alternative techniques.

Design, fabrication and testing of a serial kinematic MEMS XY stage for multifinger manipulation

In micro-electro-mechanical systems (MEMS) it is difficult to obtain a large range of motion with a small coupled error. This limitation was overcome by designing and fabricating a nested structure as a serial kinematic mechanism (SKM). In this paper, a MEMS-based XY stage is reported for multifinger manipulation application. The SKM MEMS XY stage is implemented by embedding a single degree-of-freedom (DOF) stage into another single DOF stage. The proposed MEMS XY stage is fabricated by deep reactive ion etching (DRIE) from both sides of a silicon-on-insulator (SOI) wafer. This SKM MEMS stage has the capability to generate more than 50 µm displacements along each X- and Y-axes. This nested structure also suppressed the coupled motion error to 0.6% of the original actuation displacement. For the demonstration on the micro-particle manipulation, a 15 µm sized polypropylene particle is manipulated and rotated by operating two individual fingers attached to proposed MEMS stages.

Biomechanical Analysis of the Intact and Destabilized Sheep Cervical Spine

An in vitro investigation of the biomechanics of the intact and destabilized sheep cervical spine. To establish the primary and coupled behaviors of the sheep cervical spine, levels C2-C7. Sheep spine models are often used as a precursor to human cadaveric and clinical trials. Several studies have focused on the sheep anatomy and functional spinal unit biomechanics. However, there has not been a comprehensive study of the multilevel sheep cervical spine. Adult sheep cervical spines (C2-C7) were tested in flexion-extension, lateral bending, and axial rotation, using a 6-df testing apparatus. Moment-rotation curves were generated to understand the entire loading curve. Functional spinal units were tested at various levels of destabilization by sequentially removing the stabilizing structures (i.e., ligaments, facets). The range of motion increased with caudal progression. The average total range of motion was approximately 77°, 130°, and 64° for flexion-extension, lateral bending, and axial rotation, respectively. The neutral zone accounted for a large range of motion during flexion-extension (~63%) and lateral bending (~72%). The flexion, extension, and axial rotation motion greatly increased after the removal of the capsular ligaments and facets. The C2-C3 has the largest change in motion during the various stages of destabilization. The sheep cervical spine is extremely flexible, as seen by the large range of motion and neutral zone. The large neutral zone may account for the coupled motion between axial rotation and lateral bending. The facets and capsular ligaments provide significant stability, especially in axial rotation, flexion, and extension.

Influence of Bicompartmental Knee Replacement on Stand-to-Sit Movement

Knee osteoarthritis often occurs in medial and patellofemoral compartments. A bicompartmental knee replacement system replaces these two affected knee compartments and keeps the lateral compartment and cruciate ligaments intact. It is yet to be determined whether limbs with bicompartmental knee systems can demonstrate frontal-plane knee mechanics and hamstring coactivation similar to healthy control limbs during daily activities requiring the weight-bearing knees to bend through a large range of motion (e.g., stand-to-sit). Three-dimensional knee mechanics and quadriceps and hamstring electromyographic data were collected from 8 patients with a unilateral bicompartmental knee system and 10 healthy control participants. No differences in frontal-plane knee mechanics and hamstring coactivation were found among the surgical, contralateral, and control limbs during stand-to-sit (p > .05).

Intervention Program in College Instrumental Musicians, with Kinematics Analysis of Cello and Flute Playing: A Combined Program of Yogic Breathing and Muscle Strengthening-Flexibility Exercises

College musicians encounter health risks not dissimilar to those of professional musicians. Fifteen collegiate instrumental musicians participated in the intervention program of yogic-breathing and muscle-strengthening and flexibility exercises for 8 weeks. Pre- and post-intervention data from the Health-Pain-Injury Inventory (HPI) and the Physical & Musical-Performance Efficacy Assessment Survey (PME) were analyzed for the effects of the program on the musicians' physical and musical-performance efficacy. HPI results showed that the majority of our sample had healthy lifestyles and minimal pain and injuries but irregular eating and exercise habits. The pre-intervention PME data showed a high level of musical efficacy (i.e., awareness of music technique, tone, and flow) but a low-level of physical efficacy (i.e., awareness of posture, tension, and movement flexibility). Post-intervention data showed that the program improved physical efficacy by increased awareness of posture and tension. In 2 volunteer musicians, kinematics motion analysis was conducted for exploratory purposes. Our cellist played the scale using a larger range of motion (ROM) in right shoulder flexion and abduction and slightly increased rotation while keeping decreased right elbow ROM after the intervention program. The flutist shifted the body weight from one foot to the other more in the second playing post-intervention. These changes can be attributed to the increased physical efficacy that allowed freedom to express musicality. Findings from these case scenarios provide empirically based hypotheses for further study. We share our experience so that others may use our model and instruments to develop studies with larger samples.

Development of a Magnified Mechanism for Fast Tool Servo System

Flexure-hinge mechanisms are commonly used in the design of translational micro/nanopositioning stages. They can offer a drive system with negligible friction and no need for lubrication. Usually, a large motion range requires the use of a very long actuator which could interfere with a tight workplace. A lever which amplifies the input motion of a short actuator is an effective technique to solve the problem. This paper presents the methodology for the design of a lever-type magnified flexure mechanism used for the ultra precision fast tool servo (FTS) system. A lever type hinge mechanism is designed and utilized to guide the tool holder and to preload the PZT actuator. A low capacitance PZT actuator is adopted to match the given amplifier to achieve optimum performance of device displacement. A high resolution capacitive sensor is utilized to measure the natural displacement of the tool holder. An amplifier with a multiplying factor of 12 is utilized to magnify the drive signal for the expansion and retraction of the PZT actuator. Meanwhile, the motion range of the FTS system can reach up to 98.12 μm with a primary resonant frequency of about 460 Hz, and the amplification of the lever flexure mechanism is approximately 5 as calculated from the experiment.

A Novel Large-Range XY Compliant Parallel Manipulator With Enhanced Out-of-Plane Stiffness

There is an increasing need for compact large-range XY compliant parallel manipulators (CPMs). This paper deals with a novel large-range XY CPM with enhanced out-of-plane stiffness (LRXYCPMEOS). Unlike most of XY CPMs based on the 4-PP (P: prismatic) decoupled parallel mechanism, the LRXYCPMEOS is obtained from a 4-PP-E (E: planar) decoupled parallel mechanism by replacing each P joint with a planar double multibeam parallelogram module (DMBPM) and the E joint with a spatial double multibeam parallelogram module. Normalized analytical models for the LRXYCPMEOS are then presented. As a case study, an LRXYCPMEOS with a motion range 10 mm × 10 mm in both positive directions is presented in detail, covering the geometrical parameter determination, performance characteristics analysis, actuation force check, and buckling check. The analytical models are compared with the finite element analysis (FEA) models. Finally, dynamics consideration, manufacturability, out-of-plane stiffness, and result interpretation are discussed. It is shown that the LRXYCPMEOS in the case study has the following merits: large range of motion up to 20 mm × 20 mm, enhanced out-of-plane stiffness which is approximately 7.1 times larger than the associated planar XY CPM without the spatial compliant leg, and well-constrained parasitic motion with the parasitic translation along the Z-axis less than 2 × 10−4 mm, the parasitic rotation about the X-axis/Y-axis less than 2 × 10−6 rad, and the parasitic rotation about the Z-axis below 1 × 10−6 rad.

MPI CyberMotion Simulator: Implementation of a Novel Motion Simulator to Investigate Multisensory Path Integration in Three Dimensions

Path integration is a process in which self-motion is integrated over time to obtain an estimate of one's current position relative to a starting point 1. Humans can do path integration based exclusively on visual 2-3, auditory 4, or inertial cues 5. However, with multiple cues present, inertial cues - particularly kinaesthetic - seem to dominate 6-7. In the absence of vision, humans tend to overestimate short distances (<5 m) and turning angles (<30°), but underestimate longer ones 5. Movement through physical space therefore does not seem to be accurately represented by the brain. Extensive work has been done on evaluating path integration in the horizontal plane, but little is known about vertical movement (see 3 for virtual movement from vision alone). One reason for this is that traditional motion simulators have a small range of motion restricted mainly to the horizontal plane. Here we take advantage of a motion simulator 8-9 with a large range of motion to assess whether path integration is similar between horizontal and vertical planes. The relative contributions of inertial and visual cues for path navigation were also assessed. 16 observers sat upright in a seat mounted to the flange of a modified KUKA anthropomorphic robot arm. Sensory information was manipulated by providing visual (optic flow, limited lifetime star field), vestibular-kinaesthetic (passive self motion with eyes closed), or visual and vestibular-kinaesthetic motion cues. Movement trajectories in the horizontal, sagittal and frontal planes consisted of two segment lengths (1st: 0.4 m, 2nd: 1 m; ±0.24 m/s2 peak acceleration). The angle of the two segments was either 45° or 90°. Observers pointed back to their origin by moving an arrow that was superimposed on an avatar presented on the screen. Observers were more likely to underestimate angle size for movement in the horizontal plane compared to the vertical planes. In the frontal plane observers were more likely to overestimate angle size while there was no such bias in the sagittal plane. Finally, observers responded slower when answering based on vestibular-kinaesthetic information alone. Human path integration based on vestibular-kinaesthetic information alone thus takes longer than when visual information is present. That pointing is consistent with underestimating and overestimating the angle one has moved through in the horizontal and vertical planes respectively, suggests that the neural representation of self-motion through space is non-symmetrical which may relate to the fact that humans experience movement mostly within the horizontal plane.

MPI CyberMotion Simulator: Implementation of a Novel Motion Simulator to Investigate Multisensory Path Integration in Three Dimensions

Path integration is a process in which self-motion is integrated over time to obtain an estimate of one's current position relative to a starting point 1. Humans can do path integration based exclusively on visual 2-3, auditory 4, or inertial cues 5. However, with multiple cues present, inertial cues - particularly kinaesthetic - seem to dominate 6-7. In the absence of vision, humans tend to overestimate short distances (<5 m) and turning angles (<30°), but underestimate longer ones 5. Movement through physical space therefore does not seem to be accurately represented by the brain.Extensive work has been done on evaluating path integration in the horizontal plane, but little is known about vertical movement (see 3 for virtual movement from vision alone). One reason for this is that traditional motion simulators have a small range of motion restricted mainly to the horizontal plane. Here we take advantage of a motion simulator 8-9 with a large range of motion to assess whether path integration is similar between horizontal and vertical planes. The relative contributions of inertial and visual cues for path navigation were also assessed.16 observers sat upright in a seat mounted to the flange of a modified KUKA anthropomorphic robot arm. Sensory information was manipulated by providing visual (optic flow, limited lifetime star field), vestibular-kinaesthetic (passive self motion with eyes closed), or visual and vestibular-kinaesthetic motion cues. Movement trajectories in the horizontal, sagittal and frontal planes consisted of two segment lengths (1st: 0.4 m, 2nd: 1 m; ±0.24 m/s2 peak acceleration). The angle of the two segments was either 45° or 90°. Observers pointed back to their origin by moving an arrow that was superimposed on an avatar presented on the screen.Observers were more likely to underestimate angle size for movement in the horizontal plane compared to the vertical planes. In the frontal plane observers were more likely to overestimate angle size while there was no such bias in the sagittal plane. Finally, observers responded slower when answering based on vestibular-kinaesthetic information alone. Human path integration based on vestibular-kinaesthetic information alone thus takes longer than when visual information is present. That pointing is consistent with underestimating and overestimating the angle one has moved through in the horizontal and vertical planes respectively, suggests that the neural representation of self-motion through space is non-symmetrical which may relate to the fact that humans experience movement mostly within the horizontal plane.

May 2012: This Month in JoVE

The May issue of JoVE (Journal of Visualized Experiments) includes a handful of articles that deal with the senses and perception. Specifically, articles involving gustation (taste), olfaction (smell), nociception (pain), and the vestibular senses (balance and inertial movement) will be released. The vestibular system is important for perceiving inertial movement, and inertial information is an important component of path integration. Path integration is a process by which the brain integrates multisensory information during movement, so that we maintain a sense of our body’s position, relative to a starting point. In nature, many organisms make use of this process, in order to find their way back to their nests or burrows after looking for food. This May, JoVE will publish a method filmed at the Max Plank Institute of Biological Cybernetics , which explores how path integration occurs in three dimensions. Most studies of this phenomenon are conducted in two dimensions, but thanks to a motion simulator with a large range of motion, path integration can be assessed in the horizontal and vertical planes. By controlling the sensory stimuli delivered to subjects in this device, our authors can dissect the relative contributions of visual and inertial information to estimations of starting position. Through an elegantly designed series of experiments, these investigators find that subjects are more likely to overestimate angles of movement in the horizontal plane versus the verticals. They also find that subjects were slower to point to the starting position when they had to rely only on inertial stimuli. The underlying neuronal mechanism behind path integration is poorly understood, and further experiments using this system will provide insight into how humans maintain spatial orientation during movement, which has implications that range from understanding vestibular disorders and training better pilots. Concerning gustation, JoVE will publish a procedure for isolating and culturing human fungiform taste cells this May. Back in 2010, we published an article that dealt with isolation of human fungiform papillae – a subtype of the tiny stuctures on our tongues that contain tastebuds. While papillae collection is suitable for acute experiments, long-term studies of taste cells require them to be isolated and cultured. For the first time ever reported, our authors demonstrate the isolation and culture of human fungiform taste cells and show that they can be maintained in culture for up to 8 passages, or one year. The ability to culture these cells for an extended period of time enables studies of proliferation and regeneration, and obviates the need to repeatedly collect papillae from donors. Regarding olfaction, JoVE will release an article from the Department of Agriculture, which describes an experiment that transforms the antennae of insects into a screening tool for new pesticide alternatives. After isolating plant volatile compounds via gas chromatography and mass spectrometry, these investigators screen the compounds for biological activity using the electroantennagram (EAG). Because not all of the volatile compounds emitted by plants elicit biological responses, such a bioassay is incredibly important for finding candidate molecules that can affect insect behavior. In turn, behavioral experiments, can determine whether or not a plant volatile can attract an insect. Plant volatile attractants can be used to confuse insects and potentially could serve as a safe alternative to pesticides. Thermal nociception, or the perception of noxious thermal stimuli, is the focus of an article from the University of Texas this May. Specifically, thermal nociception is investigated in Drosophila larvae using two methods: the heat probe assay and the heat plate assay. Interestingly, for both methods, larvae must first be treated with UV radiation to induce tissue damage and sensitize thermal nociceptive neurons, which usually respond with a very high threshold. As its name implies, the heat probe assay, uses a custom-built thermal probe to locally administer thermal stimuli. Nociception is quantified by recording the latency between stimulus onset and withdraw behavior. Intuitively, the second method, or heat plate assay, involves placing drosophila larvae on a heating plate within a drop of water to test whole body responses to noxious heat. Upon placement, drosophila exhibit a series of characteristic behaviors including rolling, whipping, or even seizure-like activity. When combined with genetic manipulation, these assays can provide information about the genes underlying thermal nociception – a highly conserved process, from larvae to mammals. Naturally, an exploration of the senses is not all JoVE has to offer this may. Other notable publications involve painting the pancreas to maintain orientation during histology, using an automated operant device to test multi-cognitive functions in mice, examining tamoxifen-induced apoptosis using timelapse video microscopy, and creating a convenient tool for fishing out lost samples from liquid nitrogen tanks. Stay tuned.

Why adductor magnus muscle is large: The function based on muscle morphology in cadavers

The aim of this study was to examine anatomical properties of the adductor magnus through a detailed classification, and to hypothesize its function and size to gather enough information about morphology. Ten cadaveric specimens of the adductor magnus were used. The muscle was separated into four portios (AM1-AM4) based on the courses of the corresponding perforating arteries, and its volume, muscle length, muscle fiber length and physiological cross-sectional area were assessed. The architectural characteristics of these four portions of the adductor magnus were then classified with the aid of principal component analysis. The results led us into demarcating the most proximal part of the adductor magnus (AM1) from the remaining parts (AM2, AM3, and AM4). Classification of the adductor magnus in terms of architectural characteristics differed from the more traditional anatomical distinction. The AM2, AM3, and AM4, having longer muscle fiber lengths than the AM1, appear to be designed as displacers for moving the thigh through a large range of motion. The AM1 appears instead to be oriented principally toward stabilizing the hip joint. The large mass of the adductor magnus should thus be regarded as a complex of functionally differentiable muscle portions.

Design and Modeling of a Large-Range Modular XYZ Compliant Parallel Manipulator Using Identical Spatial Modules

To meet the need for large-range high-precision motion stages, a design methodology of XYZ compliant parallel manipulators (CPMs) is introduced at first. A spatial double four-beam module and a compliant P (prismatic) joint, composed of two spatial double four-beam modules, are then proposed. Starting from a 3-PPPR (R: revolute) translational parallel manipulator, a large-range modular XYZ CPM with identical spatial modules is constructed using the proposed design approach. Normalized analytical models for the large-range modular XYZ CPM are further presented. As a case study, a modular XYZ CPM with a motion range of 10 mm × 10 mm × 10 mm along the positive X-, Y-, and Z-axes is presented in detail, covering the geometrical parameter determination, performance characteristics analysis, buckling check, and actuation force check. The analytical models are compared with the finite element analysis (FEA) models. Finally, the dynamics consideration, manufacturability, and merits are discussed. It is shown that the proposed large-range modular XYZ CPM has the following main merits compared with existing designs: (1) large range of motion up to 20 mm × 20 mm × 20 mm and (2) reduced number of design parameters through the use of identical spatial modules, although the manufacturability is a challenging issue.

Bilateral anterior and posterior glenohumeral stabilization using Achilles tendon allograft augmentation in a patient with Ehlers-Danlos syndrome

Generalized joint hypermobility is a potentially incapacitating manifestation of connective tissue disorders, the commonest of which is Ehlers-Danlos Syndrome (EDS). 9 Diaz J.A. Cohen S.B. Warren R.F. Craig E.V. Allen A.A. Arthrodesis as a salvage procedure for recurrent instability of the shoulder. J Shoulder Elbow Surg. 2003; 1: 237-241https://doi.org/10.1016/S1058-2746(02)86883-5 Abstract Full Text Full Text PDF Scopus (29) Google Scholar EDS is a phenotypically and genetically heterogeneous disorder caused by abnormal collagen synthesis and cross-linking. 4 Beighton P. De Paepe A. Steinmann B. Tsipouras P. Wenstrup R.J. Ehlers-Danlos syndromes: revised nosology, Villefranche, 1997. Am J Med Genet. 1998; 7: 31-37 Crossref Scopus (1337) Google Scholar The cardinal manifestations of EDS consist of hyperextensible skin, joint hypermobility, dystrophic scarring, and connective tissue fragility. 25 Steinmann B. Royce P.M. Superti-Furga A. The Ehlers-Danlos syndrome. in: Royce P.M. Steinmann B. Connective tissue and its heritable disorders: molecular, genetic, and medical aspects. 2nd ed. John Wiley & Sons, Hoboken2003: 431-523 Google Scholar Joint laxity and hypermobility in EDS occurs as a consequence of increased elasticity and length of restraining structures such as joint capsules, ligaments, and tendons. 17 Johnson S.M. Robinson C.M. Shoulder instability in patients with joint hyperlaxity. J Bone Joint Surg Am. 2010; 9: 1545-1557https://doi.org/10.2106/JBJS.H.00078 Crossref Scopus (74) Google Scholar In particular, patients with hypermobility-type EDS (type III) have a larger range of motion and lower level of sports activity compared with controls. 23 Rombaut L. De Paepe A. Malfait F. Cools A. Calders P. Joint position sense and vibratory perception sense in patients with Ehlers-Danlos syndrome type III (hypermobility type). Clin Rheumatol. 2009; 29: 289-295https://doi.org/10.1007/s10067-009-1320-y Crossref Scopus (57) Google Scholar Joint instability with secondary tendonitis and chronic joint pain are common sequelae. 24 Stanitski D.F. Nadjarian R. Stanitski C.L. Bawle E. Tsipouras P. Orthopaedic manifestations of Ehlers-Danlos syndrome. Clin Orthop Relat Res. 2000; 376: 213-221 Crossref PubMed Scopus (72) Google Scholar Hypermobility-type EDS patients have also been proposed to be more prone to joint instability due to altered proprioception and vibratory perception; however, a case-control study did not find any sensory variations between EDS and control patients. 23 Rombaut L. De Paepe A. Malfait F. Cools A. Calders P. Joint position sense and vibratory perception sense in patients with Ehlers-Danlos syndrome type III (hypermobility type). Clin Rheumatol. 2009; 29: 289-295https://doi.org/10.1007/s10067-009-1320-y Crossref Scopus (57) Google Scholar

A Physician's Guide to the Physical Examination of the Shoulder

Shoulder pain is the third most frequent musculoskeletal complaint presented to physicians. Often considered a benign entity by patients and even their physicians, shoulder disorders can have a devastating effect on a patient's ability to function, as well as serve as an indicator of poor general health. For these reasons, it is important for the physician to be able to identify the etiology of a patient's shoulder problem(s). However, making a correct diagnosis is often difficult because there can be many causes for a patient's shoulder pain, weakness, or loss of function. Moreover, the shoulder girdle is an intricate group of structures that work together to allow for the largest range of motion in the body. This complexity makes it difficult to diagnose a patient's condition(s) based on history alone. A thorough and well-performed physical examination is the key to making a correct diagnosis and helping to distinguish different etiologies of shoulder dysfunction. In this article, we review relevant shoulder anatomy and biomechanics, and general shoulder examinations with special tests for various shoulder pathologies. We provide an effective and methodical approach to the physical examination of the shoulder.

A New Flexure Revolute Joint with Leaf springs and Its Application to Large Workspace Parallel Robot

This paper presents a flexure revolute joint with a large range of motion which can be used as a joint in a parallel robot with a large workspace. We proposed a new structure of flexure revolute joint. The joint consists of leaf springs which are symmetrically arranged between two frames. The shape of the frame is like a spiral stairs. Arrangement of leaf springs was proposed taking into consideration the axis drift and stiffness characteristics of the joint while achieving a large range of motion. Characteristics of the proposed joint were investigated by Finite Element Analysis (FEA) and experiments. A planar parallel robot with two degrees of freedom using the proposed joints was designed and fabricated. Its workspace, position repeatability and stiffness were experimentally investigated.

A millimeter-range flexure-based nano-positioning stage using a self-guided displacement amplification mechanism

We propose a mechanism for a single-axis flexure-based nano-positioning stage. A self-guided displacement amplification mechanism enables a large range of motion—up to a millimeter—with a compact stage size. Our device has a skewed double-compound parallelogram structure that acts as a motion guide and provides displacement amplification, thereby eliminating a serial connection. Its structural symmetry improves positioning accuracy by reducing parasitic motion error and thermal deformation. A millimeter-range piezo-actuated nano-positioning stage is implemented using the self-guided displacement amplification mechanism. The stage was designed using design optimization frameworks to obtain the highest fundamental resonance frequency under constraints for predetermined travel range, stress, and size. The effectiveness of the proposed mechanism is experimentally verified. Also, we demonstrate that the fabricated stage has superior volume efficency compared to other stages of similar size.