Glenohumeral muscle force and moment mechanics in a position of shoulder instability

Bassett, Rick W.; Browne, Anthony; Morrey, B.F.; An, Kai Nan

doi:10.1016/0021-9290(90)90295-e

Cited by 243 publications

(117 citation statements)

References 11 publications

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“…[12][13][14] Bassett et al measured moment arm data in five specimens with the shoulder in the 908 abduction and 908 external rotation by taking serial crosssections of the joint and geometrically determining distances from joint center to muscle centroids. Kuechle et al measured instantaneous moment arms via the tendon excursion method in 10 specimens in four elevation positions.…”

Section: Introductionmentioning

confidence: 99%

Variation in external rotation moment arms among subregions of supraspinatus, infraspinatus, and teres minor muscles

Langenderfer

Patthanacharoenphon

Carpenter

et al. 2006

Journal Orthopaedic Research

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A rotator cuff tear causes morphologic changes in rotator cuff muscles and tendons and reduced shoulder strength. The mechanisms by which these changes affect joint strength are not understood. This study's purpose was to empirically determine rotation moment arms for subregions of supraspinatus, infraspinatus, and for teres minor, and to test the hypothesis that subregions of the cuff tendons increase their effective moment arms through connections to other subregions. Tendon excursions were measured for full ranges of rotation on 10 independent glenohumeral specimens with the humerus abducted in the scapular plane at 10 and 608. Supraspinatus and infraspinatus tendons were divided into equal width subregions. Two conditions were tested: tendon divided to the musculotendinous junction, and tendon divided to the insertion on the humerus. Moment arms were determined from tendon excursion via the principle of virtual work. Moment arms for the infraspinatus (p < 0.001) and supraspinatus (p < 0.001) were significantly greater when the tendon was only divided to the musculotendinous junction versus division to the humeral head. Moment arms across subregions of infraspinatus (p < 0.001) and supraspinatus (p < 0.001) were significantly different. A difference in teres minor moment arm was not found for the two cuff tendon conditions. Moment arm differences between muscle subregions and for tendon division conditions have clinical implications. Interaction between cuff regions could explain why some subjects retain strength after a small cuff tear. This finding helps explain why a partial cuff repair may be beneficial when a complete repair is not possible. Data presented here can help differentiate between cuff tear cases that would benefit from cuff repair and cases for which cuff repair might not be as favorable. ß

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Section: Introductionmentioning

confidence: 99%

Variation in external rotation moment arms among subregions of supraspinatus, infraspinatus, and teres minor muscles

Langenderfer

Patthanacharoenphon

Carpenter

et al. 2006

Journal Orthopaedic Research

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“…Previous authors have measured muscle architecture (Amis et al, 1979;Bassett et al, 1990;Veeger et al, 1991Veeger et al, , 1997 and moment arms (Otis et al, 1994;Kuechle et al, 1997Kuechle et al, , 2000Hughes et al, 1998) at the shoulder. Due to parameter variability and covariance, it is advantageous to measure parameters in conjunction with one another, rather than to use parameters from different data-sets (Hoffer et al, 1989;Hoy et al, 1990;Loren et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Variability in isometric force and moment generating capacity of glenohumeral external rotator muscles

Langenderfer

Patthanacharoenphon

Carpenter

et al. 2006

Clinical Biomechanics

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Background. Muscles which cause glenohumeral external rotation possess varying ability for generating force and moment due to differences in muscle architecture, moment arm, and the interaction of these two factors. This study's purpose was to determine a complete dataset of muscletendon parameters for predicting the moment generating capacity and force-length dependence for external rotation of infraspinatus, supraspinatus and teres minor muscles.Methods. Muscle fascicle length, sarcomere length, pennation angle, and muscle volume were measured for sub-regions of infraspinatus and supraspinatus, and teres minor from 10 glenohumeral specimens. Tendon excursion was measured for glenohumeral rotation. From these parameter measurements, optimal fascicle length, physiological cross-sectional area, muscle force-length dependence, and maximum isometric moment generating capacity were calculated.Findings. Substantial differences were found for optimal muscle length, physiologic cross-sectional area, and tendon length for the 10 specimens of this study. Muscle sub-region had a significant effect on the force-length relationship for infraspinatus (P < 0.001), but was not significant for supraspinatus (P = 0.49). For infraspinatus and supraspinatus, maximum isometric rotation moment capacity was greater at 10° versus 60° abduction (P < 0.001). Maximum isometric rotation moment capacity for the teres minor was greater at 10° versus 60° abduction (P < 0.01). Sub-regions demonstrated significant differences in isometric moment capacity (P < 0.001).Interpretation. Functional capabilities of these muscles depend on muscle architecture and moment arm as well as their combined effects. The results allow for development of stochastic and deterministic models of glenohumeral external rotation strength which can be used for prediction of muscle forces and joint moments.

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“…Observations of musculoskeletal parameters also exhibit variability. 1,6,61,77 One might hypothesize that the variation in strength can be explained via quantifiable differences in musculoskeletal parameter variability, specifically physiologic cross-sectional areas (PCSA), moment arms and the muscle length-tension relationships.…”

Section: Introductionmentioning

confidence: 99%

A Probabilistic Model of Glenohumeral External Rotation Strength for Healthy Normals and Rotator Cuff Tear Cases

et al. 2006

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The reigning paradigm of musculoskeletal modeling is to construct deterministic models from parameters of an "average" subject and make predictions for muscle forces and joint torques with this model. This approach is limited because it does not perform well for outliers, and it does not model the effects of population parameter variability. The purpose of this study was to simulate variability in musculoskeletal parameters on glenohumeral external rotation strength in healthy normals, and in rotator cuff tear cases using a Monte Carlo model. The goal was to determine if variability in musculoskeletal parameters could quantifiably explain variability in glenohumeral external rotation strength. Multivariate Gamma distributions for musculoskeletal architecture and moment arm were constructed from empirical data. Gamma distributions of measured joint strength were constructed. Parameters were sampled from the distributions and input to the model to predict muscle forces and joint torques. The model predicted measured joint torques for healthy normals, subjects with supraspinatus tears, and subjects with infraspinatus-supraspinatus tears with small error. Muscle forces for the three conditions were predicted and compared. Variability in measured torques can be explained by differences in parameter variability.

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Glenohumeral muscle force and moment mechanics in a position of shoulder instability

Cited by 243 publications

References 11 publications

Variation in external rotation moment arms among subregions of supraspinatus, infraspinatus, and teres minor muscles

Variation in external rotation moment arms among subregions of supraspinatus, infraspinatus, and teres minor muscles

Variability in isometric force and moment generating capacity of glenohumeral external rotator muscles

A Probabilistic Model of Glenohumeral External Rotation Strength for Healthy Normals and Rotator Cuff Tear Cases

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