Biomechanical model of the human shoulder--I. Elements.

In a first step of a biomechanical modelling of the human shoulder the points of application of muscle forces to the bones were determined in a dissection study on four human shoulder specimens. A kinematic description of the shoulder was presented employing bone fixed coordinate systems. Actions of the shoulder muscles were modelled as a system of forces acting along ideal strings. The shoulder complex was treated as a three rigid body twelve degrees of freedom system.