Roles of deltoid and rotator cuff muscles in shoulder elevation

Liu, J; Hughes, R. E.; Smutz, W. Paul; Niebur, Glen L.; Nan-An, K

doi:10.1016/s0268-0033(96)00047-2

Cited by 157 publications

(134 citation statements)

References 18 publications

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“…The resulting curves corresponded well with published cadaver measurements (e.g. Liu et al, 1997;Otis et al, 1994). Although the humerus was free to translate in any direction, only the translation in the inferior-superior direction was presented here.…”

Section: Discussionsupporting

confidence: 84%

Effect of supraspinatus deficiency on humerus translation and glenohumeral contact force during abduction

Terrier

Reist

Vogel

et al. 2007

Clinical Biomechanics

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Background. Supraspinatus deficiency is the most frequent and important problem associated to rotator cuff pathologies. It reduces shoulder stability and can lead to osteoarthritis. The goal of this study was to develop a numerical model of the shoulder to analyse the biomechanical consequences of this pathology.Methods. A 3D finite element model of the shoulder was developed from a normal cadaver specimen. It included the scapula, the humerus and the major abduction muscles. Instead of the usual ball-socket assumption, which prevents the natural translation of the humerus, shoulder stability was actively achieved by muscles. A feedback algorithm was developed to synchronise muscle forces during abduction. The numerical algorithm was validated against an algebraic model, and the calculated muscle moment arms were compared to the literature. Two cases were considered: a normal shoulder and the same one without supraspinatus.Findings. For the normal shoulder, the model predicted the initial upward migration of the humeral head. The maximal humerus translation occurred at 30°of abduction and was 0.75 mm above its ideal centered position. Without supraspinatus, it was 1.6 times higher and the contact point in the glenoid fossa was more eccentric. For the normal shoulder, the maximal glenohumeral force was 81% of the body weight, at 82°of abduction. Without supraspinatus, it increased by 8%, while the increase of muscle forces was 30%.Interpretation. Supraspinatus deficiency increased the upward migration of the humerus, the eccentric loading, and the joint and muscle forces, which may cause a limitation of active abduction and degenerative glenohumeral changes (osteoarthritis and the rotator cuff tear).

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Section: Discussionsupporting

confidence: 84%

Effect of supraspinatus deficiency on humerus translation and glenohumeral contact force during abduction

Terrier

Reist

Vogel

et al. 2007

Clinical Biomechanics

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“…The reported values of humerus translation, muscle moment arms, and joint forces are consistent with the literature (Graichen et al, 2000;Hughes et al, 1998;Kelkar et al, 2001;Liu et al, 1997;Massimini et al, 2008;Poppen and Walker, 1978;Westerhoff et al, 2009). Using a 2D (axisymmetric) model of the glenoid component, Swieszkowski et al also reported that increasing glenoid thickness reduces the maximal contact pressure (Swieszkowski et al, 2003).…”

Section: Discusionsupporting

confidence: 84%

Importance of polyethylene thickness in total shoulder arthroplasty: A finite element analysis

Terrier

Brighenti

Pioletti

et al. 2012

Clinical Biomechanics

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Background: Articular surfaces reconstruction is essential in total shoulder arthroplasty. Because of the limited glenoid bone support, thin glenoid component could improve anatomical reconstruction, but adverse mechanical effects might appear. Methods: With a numerical musculoskeletal shoulder model, we analysed and compared three values of thickness of a typical all-polyethylene glenoid component: 2, 4 (reference) and 6 mm. A loaded movement of abduction in the scapular plane was simulated. We evaluated the humeral head translation, the muscle moment arms, the joint force, the articular contact pattern, and the polyethylene and cement stress. Findings Decreasing polyethylene thickness from 6 to 2 mm slightly increased humeral head translation and muscle moment arms. This induced a small decreased of the joint reaction force, but important increase of stress within the polyethylene and the cement mantel. Interpretation The reference thickness of 4 mm seems a good compromise to avoid stress concentration and joint stuffing.

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“…This rotational effect of an applied force is called torque or moment. The torque that a muscle generates on the joint is influenced by the moment arm range or the force production capacity of the joint 4,5,6 .…”

Section: Introductionmentioning

confidence: 99%

“…The magnitude of the moment arm represents the mechanical advantage of a muscle in a joint, and its measurement may assist in understanding how the muscle functions 5 .…”

Section: Introductionmentioning

confidence: 99%

Critérios mecânicos para progressão de exercícios de rotação interna e externa do ombro no plano sagital

Toledo

Ribeiro

Loss

2007

Rev. bras. fisioter.

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Introduction: Knowledge of torque and force production capacity and moment arm patterns throughout the movement, and their influence on the torque produced, are essential for understanding human movement and may be of great use for controlling the overload imposed on the muscle-tendon structure. Objective: To present mechanical criteria for progression in internal rotation (IR) and external rotation (ER) exercises of the shoulder in the sagittal plane. Method: Six individuals were assessed using an isokinetic dynamometer and an electrogoniometer. From the data collected, the mean torque, mean resultant force and weighted mean moment arm were calculated using the SAD32 and Matlab ® software. Results: The angles at which the peak ER and IR torque occurred were -34° and 6º with values of 43 Nm and 69 Nm, respectively. The peaks for ER and IR muscle force were at 35º and -14º, and the values at these angles were 10227 N and 8464 N, respectively. The weighted mean moment arm for ER presented an increasing pattern over the whole range of motion (ROM) and the peak was at the end of the ROM, i.e. at -50º (0.91 cm). The weighted mean moment arm for IR was almost constant with its peak at 50º (0.96 cm). Conclusion: The mechanical criteria for progression in internal and external rotation exercises of the shoulder are torque, force and weighted mean moment arm because different overloads on the muscle-tendon structure can be caused according to their patterns over the ROM.

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Roles of deltoid and rotator cuff muscles in shoulder elevation

Cited by 157 publications

References 18 publications

Effect of supraspinatus deficiency on humerus translation and glenohumeral contact force during abduction

Effect of supraspinatus deficiency on humerus translation and glenohumeral contact force during abduction

Importance of polyethylene thickness in total shoulder arthroplasty: A finite element analysis

Critérios mecânicos para progressão de exercícios de rotação interna e externa do ombro no plano sagital

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