scholarly journals The passive stiffness of the wrist and forearm

2012 ◽  
Vol 108 (4) ◽  
pp. 1158-1166 ◽  
Author(s):  
Domenico Formica ◽  
Steven K. Charles ◽  
Loredana Zollo ◽  
Eugenio Guglielmelli ◽  
Neville Hogan ◽  
...  
Keyword(s):  
Wrist Joint ◽  
Rehabilitation Robot ◽  
Passive Stiffness ◽  
Ulnar Deviation ◽  
The Past ◽  
Stiffness Matrices ◽  
Flexion Extension ◽  
Stiffness Characteristics ◽  
Wrist Stiffness ◽  
Rotation Dynamics

Because wrist rotation dynamics are dominated by stiffness (Charles SK, Hogan N. J Biomech 44: 614–621, 2011), understanding how humans plan and execute coordinated wrist rotations requires knowledge of the stiffness characteristics of the wrist joint. In the past, the passive stiffness of the wrist joint has been measured in 1 degree of freedom (DOF). Although these 1-DOF measurements inform us of the dynamics the neuromuscular system must overcome to rotate the wrist in pure flexion-extension (FE) or pure radial-ulnar deviation (RUD), the wrist rarely rotates in pure FE or RUD. Instead, understanding natural wrist rotations requires knowledge of wrist stiffness in combinations of FE and RUD. The purpose of this report is to present measurements of passive wrist stiffness throughout the space spanned by FE and RUD. Using a rehabilitation robot designed for the wrist and forearm, we measured the passive stiffness of the wrist joint in 10 subjects in FE, RUD, and combinations. For comparison, we measured the passive stiffness of the forearm (in pronation-supination), as well. Our measurements in pure FE and RUD agreed well with previous 1-DOF measurements. We have linearized the 2-DOF stiffness measurements and present them in the form of stiffness ellipses and as stiffness matrices useful for modeling wrist rotation dynamics. We found that passive wrist stiffness was anisotropic, with greater stiffness in RUD than in FE. We also found that passive wrist stiffness did not align with the anatomical axes of the wrist; the major and minor axes of the stiffness ellipse were rotated with respect to the FE and RUD axes by ∼20°. The direction of least stiffness was between ulnar flexion and radial extension, a direction used in many natural movements (known as the “dart-thrower's motion”), suggesting that the nervous system may take advantage of the direction of least stiffness for common wrist rotations.

Kinematic Analysis of Relative Motion within the Proximal Carpal Row

1993 ◽  
Vol 18 (5) ◽  
pp. 609-612 ◽  
Author(s):  
G. R. SENNWALD ◽  
V. ZDRAVKOVIC ◽  
H. A. C. JACOB ◽  
H. P. KERN
Keyword(s):  
Relative Motion ◽  
Kinematic Analysis ◽  
Wrist Joint ◽  
Helical Axis ◽  
Ulnar Deviation ◽  
Flexion Extension

The motions of the scaphoid and triquetrum relative to the lunate have been studied on cadaver specimens. The helical axis concept was applied. The wrist motions performed were flexion-extension and radial-ulnar deviation. The results showed increased relative motion of the scaphoid towards terminal extension, and to a lesser amount in the case of the triquetrum, towards terminal flexion. The lunate might be considered as a keystone in the proximal carpal row when wrist stability is considered. It is doubly intercalated: longitudinally and transversely. Wrist ligaments co-ordinate the positioning of the bones in the mid-range of carpal motions, and restrict further motion in extreme positions of the wrist joint.

scholarly journals Gender Differences in Capitate Kinematics are Eliminated After Accounting for Variation in Carpal Size

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Michael J. Rainbow ◽  
Joseph J. Crisco ◽  
Douglas C. Moore ◽  
Scott W. Wolfe
Keyword(s):  
Gender Differences ◽  
Wrist Joint ◽  
Carpal Bone ◽  
Ulnar Deviation ◽  
Rotation Axes ◽  
Flexion Extension ◽  
Optical Motion ◽  
Joint Center ◽  
Best Fit

Previous studies have found gender differences in carpal kinematics, and there are discrepancies in the literature on the location of the flexion∕extension and radio-ulnar deviation rotation axes of the wrist. It has been postulated that these differences are due to carpal bone size differences rather than gender and that they may be resolved by normalizing the kinematics by carpal size. The purpose of this study was to determine if differences in radio-capitate kinematics are a function of size or gender. We also sought to determine if a best-fit pivot point (PvP) describes the radio-capitate joint as a ball-and-socket articulation. By using an in vivo markerless bone registration technique applied to computed tomography scans of 26 male and 28 female wrists, we applied scaling derived from capitate length to radio-capitate kinematics, characterized by a best-fit PvP. We determined if radio-capitate kinematics behave as a ball-and-socket articulation by examining the error in the best-fit PvP. Scaling PvP location completely removed gender differences (P=0.3). This verifies that differences in radio-capitate kinematics are due to size and not gender. The radio-capitate joint did not behave as a perfect ball and socket because helical axes representing anatomical motions such as flexion-extension, radio-ulnar deviation, dart throwers, and antidart throwers, were located at distances up to 4.5mm from the PvP. Although the best-fit PvP did not yield a single center of rotation, it was still consistently found within the proximal pole of the capitate, and rms errors of the best-fit PvP calculation were on the order of 2mm. Therefore, the ball-and-socket model of the wrist joint center using the best-fit PvP is appropriate when considering gross motion of the hand with respect to the forearm such as in optical motion capture models. However, the ball-and-socket model of the wrist is an insufficient description of the complex motion of the capitate with respect to the radius. These findings may aid in the design of wrist external fixation and orthotics.

Practical Application of a Biaxial Goniometer to the Wrist Joint

1995 ◽  
Vol 39 (10) ◽  
pp. 558-562
Author(s):  
Bryan Buchholz ◽  
Helen Wellman
Keyword(s):  
Wrist Joint ◽  
Forearm Rotation ◽  
Wrist Movement ◽  
Calibration Technique ◽  
Ulnar Deviation ◽  
Angle Measurements ◽  
Flexion Extension ◽  
Angular Data ◽  
Mathematical Equations ◽  
Goniometric Measurements

The objectives of this study were: 1) to determine errors in wrist angle measurements from a commercially-available biaxial electrogoniometer and 2) to develop a calibration routine in order to correct for these errors. Goniometric measurements were simultaneously collected with true angular data using a fixture that allowed wrist movement in one plane while restricting motion in the orthogonal plane. These data were collected in two sets of trials: 1) flexion/extension with radial/ulnar deviation restricted and 2) radial/ulnar deviation with flexion/extension restricted. During these trials, discrete 30 degree increments of forearm rotation were studied. The results showed the expected cross talk and zero drift errors during forearm rotation. The application of mathematical equations that describe the effect of goniometer twist during forearm rotation resulted in significant error reduction for most trials. The calibration technique employs both a slope and a displacement transformation to improve the accuracy of angular data. The calibration technique may be used on data collected in the field if forearm rotation is measured simultaneously with the goniometer data.

scholarly journals Wrist Position Sense in Two Dimensions: Between-Hand Symmetry and Anisotropic Accuracy Across the Space

2021 ◽  
Vol 15 ◽  
Author(s):  
Giulia A. Albanese ◽  
Michael W. R. Holmes ◽  
Francesca Marini ◽  
Pietro Morasso ◽  
Jacopo Zenzeri
Keyword(s):  
Wrist Joint ◽  
Position Sense ◽  
Two Dimensions ◽  
Joint Position ◽  
Wrist Flexion ◽  
Ulnar Deviation ◽  
Target Direction ◽  
Wrist Position ◽  
Flexion Extension ◽  
Combined Movements

A deep investigation of proprioceptive processes is necessary to understand the relationship between sensory afferent inputs and motor outcomes. In this work, we investigate whether and how perception of wrist position is influenced by the direction along which the movement occurs. Most previous studies have tested Joint Position Sense (JPS) through 1 degree of freedom (DoF) wrist movements, such as flexion/extension (FE) or radial/ulnar deviation (RUD). However, the wrist joint has 3-DoF and many activities of daily living produce combined movements, requiring at least 2-DoF wrist coordination. For this reason, in this study, target positions involved movement directions that combined wrist flexion or extension with radial or ulnar deviation. The chosen task was a robot-aided Joint Position Matching (JPM), in which blindfolded participants actively reproduced a previously passively assumed target joint configuration. The JPM performance of 20 healthy participants was quantified through measures of accuracy and precision, in terms of both perceived target direction and distance along each direction of movement. Twelve different directions of movement were selected and both hands tested. The left and right hand led to comparable results, both target extents and directions were differently perceived according to the target direction on the FE/RUD space. Moreover, during 2-DoF combined movements, subjects’ perception of directions was impaired when compared to 1-DoF target movements. In summary, our results showed that human perception of wrist position on the FE/RUD space is symmetric between hands but not isotropic among movement directions.

Stiffness, not inertial coupling, determines path curvature of wrist motions

2012 ◽  
Vol 107 (4) ◽  
pp. 1230-1240 ◽  
Author(s):  
Steven K. Charles ◽  
Neville Hogan
Keyword(s):  
Realistic Model ◽  
Laser Pointer ◽  
Dominant Term ◽  
Ulnar Deviation ◽  
Inertial Coupling ◽  
Planning And Control ◽  
Flexion Extension ◽  
Path Curvature ◽  
And Control ◽  
Wrist Stiffness

When humans rotate their wrist in flexion-extension, radial-ulnar deviation, and combinations, the resulting paths (like the path of a laser pointer on a screen) exhibit a distinctive pattern of curvature. In this report we show that the passive stiffness of the wrist is sufficient to account for this pattern. Simulating the dynamics of wrist rotations using a demonstrably realistic model under a variety of conditions, we show that wrist stiffness can explain all characteristics of the observed pattern of curvature. We also provide evidence against other possible causes. We further demonstrate that the phenomenon is robust against variations in human wrist parameters (inertia, damping, and stiffness) and choice of model inputs. Our findings explain two previously observed phenomena: why faster wrist rotations exhibit more curvature and why path curvature rotates with pronation-supination of the forearm. Our results imply that, as in reaching, path straightness is a goal in the planning and control of wrist rotations. This requires humans to predict and compensate for wrist dynamics, but, unlike reaching, nonlinear inertial coupling (e.g., Coriolis acceleration) is insignificant. The dominant term to be compensated is wrist stiffness.

Practical Operation of a Biaxial Goniometer at the Wrist Joint

1997 ◽  
Vol 39 (1) ◽  
pp. 119-129 ◽  
Author(s):  
Bryan Buchholz ◽  
Helen Wellman
Keyword(s):  
Wrist Joint ◽  
Forearm Rotation ◽  
Calibration Technique ◽  
Ulnar Deviation ◽  
Angle Measurements ◽  
Practical Operation ◽  
Flexion Extension ◽  
Angular Data ◽  
Mathematical Equations ◽  
Goniometric Measurements

The objectives of this study were (a) to determine errors in wrist angle measurements from a commercially available biaxial electrogoniometer and (b) to develop a calibration routine in order to correct for these errors. Goniometric measurements were collected simultaneously with true angular data using a fixture that allowed wrist movement in one plane while restricting motion in the orthogonal plane. These data were collected in two sets of trials: flexion/extension with radial/ulnar deviation restricted, and radial/ulnar deviation with flexion/extension restricted. During these trials, we studied discrete 30° increments of forearm rotation. The results showed the expected cross talk and zero drift errors during forearm rotation. The application of mathematical equations that describe the effect of goniometer twist resulted in significant error reduction for most forearm rotations. The calibration technique employs both a slope and a displacement transformation to improve the accuracy of angular data. The calibration technique may be used on data collected in the field if forearm rotation is measured simultaneously with the goniometer data.

Influence of Joint Laxity on Scaphoid Kinematics

1995 ◽  
Vol 20 (3) ◽  
pp. 379-382 ◽  
Author(s):  
M. GARCIA-ELIAS ◽  
M. RIBE ◽  
J. RODRIGUEZ ◽  
M. COTS ◽  
J. CASAS
Keyword(s):  
Sagittal Plane ◽  
Wrist Joint ◽  
Frontal Plane ◽  
Joint Laxity ◽  
Lateral Deviation ◽  
Ulnar Deviation ◽  
Flexion Extension ◽  
Out Of Plane ◽  
Kinematic Behaviour ◽  
Mechanical Factors

Excessively lax wrists more frequently become symptomatic if overloaded or injured than normal joints. Whether this is the consequence of biological or mechanical factors or both remains unknown. This study evaluates the relationship between the degree of joint laxity and scaphoid kinematic behaviour during radio-ulnar deviation of the wrist in 60 normal volunteers. There is a significant linear relationship between the direction of scaphoid rotation and the amount of wrist joint laxity. During lateral deviation of the wrist, joints that are more lax have a scaphoid rotating mainly along the sagittal plane of flexion and extension, with little lateral deviation. In contrast, the scaphoid of volunteers with decreased laxity rotate mostly along the frontal plane of radio-ulnar deviation with minimal flexion extension. These results support the concept of increased out-of-plane scaphoid rotation as a factor of increased vulnerability during over-work or injury.

scholarly journals Accuracy and repeatability of wrist joint angles in boxing using an electromagnetic tracking system

2019 ◽  
Vol 23 (1) ◽  
Author(s):  
Ian T. Gatt ◽  
Tom Allen ◽  
Jon Wheat
Keyword(s):  
Wrist Joint ◽  
Tracking System ◽  
Testing Procedure ◽  
Electromagnetic Tracking ◽  
Good Reliability ◽  
Flexion Extension ◽  
In Vivo Testing ◽  
Accuracy And Repeatability ◽  
Electromagnetic Tracking System

AbstractThe hand-wrist region is reported as the most common injury site in boxing. Boxers are at risk due to the amount of wrist motions when impacting training equipment or their opponents, yet we know relatively little about these motions. This paper describes a new method for quantifying wrist motion in boxing using an electromagnetic tracking system. Surrogate testing procedure utilising a polyamide hand and forearm shape, and in vivo testing procedure utilising 29 elite boxers, were used to assess the accuracy and repeatability of the system. 2D kinematic analysis was used to calculate wrist angles using photogrammetry, whilst the data from the electromagnetic tracking system was processed with visual 3D software. The electromagnetic tracking system agreed with the video-based system (paired t tests) in both the surrogate (< 0.2°) and quasi-static testing (< 6°). Both systems showed a good intraclass coefficient of reliability (ICCs > 0.9). In the punch testing, for both repeated jab and hook shots, the electromagnetic tracking system showed good reliability (ICCs > 0.8) and substantial reliability (ICCs > 0.6) for flexion–extension and radial-ulnar deviation angles, respectively. The results indicate that wrist kinematics during punching activities can be measured using an electromagnetic tracking system.

scholarly journals Myoelectric Control Techniques for a Rehabilitation Robot

2011 ◽  
Vol 8 (1) ◽  
pp. 21-37 ◽  
Author(s):  
Alan Smith ◽  
Edward E. Brown
Keyword(s):  
Healthy Subjects ◽  
Sagittal Plane ◽  
Robot Manipulator ◽  
Wrist Joint ◽  
Elbow Flexion ◽  
Myoelectric Control ◽  
Average Error ◽  
Rehabilitation Robot ◽  
Control Scheme ◽  
Central Cord Syndrome

This work examines two different types of myoelectric control schemes for the purpose of rehabilitation robot applications. The first is a commonly used technique based on a Gaussian classifier. It is implemented in real time for healthy subjects in addition to a subject with Central Cord Syndrome (CCS). The myoelectric control scheme is used to control three degrees of freedom (DOF) on a robot manipulator which corresponded to the robot's elbow joint, wrist joint, and gripper. The classes of motion controlled include elbow flexion and extension, wrist pronation and supination, hand grasping and releasing, and rest. Healthy subjects were able to achieve 90% accuracy. Single DOF controllers were first tested on the subject with CCS and he achieved 100%, 96%, and 85% accuracy for the elbow, gripper, and wrist controllers respectively. Secondly, he was able to control the three DOF controller at 68% accuracy. The potential applications for this scheme are rehabilitation and teleoperation. To overcome limitations in the pattern recognition based scheme, a second myoelectric control scheme is also presented which is trained using electromyographic (EMG) data derived from natural reaching motions in the sagittal plane. This second scheme is based on a time delayed neural network (TDNN) which has the ability to control multiple DOF at once. The controller tracked a subject's elbow and shoulder joints in the sagittal plane. Results showed an average error of 19° for the two joints. This myoelectric control scheme has the potential of being used in the development of exoskeleton and orthotic rehabilitation applications.

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