An innovative 2D-mesh model to improve deltoid moment arms, muscle forces and glenohumeral joint reaction force estimations

We proposed a 2D-mesh representation of the deltoid muscle to improve a realism of forces and moments predictions in a multibody shoulder model. Our 2D-mesh model was qualitatively compared to a commonly used via-point model during an arm elevation in the scapular plane and to previous in-vitro studies in terms of deltoid moment arms. The most notable improvement was observed for the moment arms of the anterior deltoid, which shows better agreement with in-vitro studies. Consequently, joint reaction force above 90{degrees} of arm elevation was more consistent with in-vivo data, validating the 2D-mesh representation of the deltoid muscle.