Sterno-clavicular kinematics : a new measurement system

Abstract

The study of the human motion as a discipline is ancient almost like the man. Early theories and observations on these topics can be found in Hyppocrates' and Galeno's work. More recently Duchenne de Boulogne (1867), Marey (1885), Braune and Fisher (1888), Sherrington (1933), Luria and finally Haken (1996) applied new techniques to the study of movement trying to understand and localise also the main areas of the brain involved during motion. Despite the richness of the literature produced, "man in motion" still represents a fascinating and partially unknown theme to deal with, particularly in the dynamic behaviour of the arms during the execution of specific tasks. Such movement, indeed individual expression of the complex interaction of biological subsystems (brain, muscles, skeleton, etc. ) against the surrounding environment, hides nowadays its features and very few data are available on its kinematic and dynamic response. This gap is largely due to the lack of knowledge on the dynamic movement of the "shoulder complex" and of the related muscles involved during motion. In fact, the large number of degrees of freedom to be measured and the high deformability of skin and soft tissues prevent the direct measurement of skeletal movements and contribute to increment the above described indetermination. Against this complex background, the rehabilitationist faces the pragmatic difficulties to decide which joints require attention as a priority or, in the case of biological damage, to assess the degree of impairment and subsequent recovery. As a result, clinical assessmentis performed by the use of relatively elementary test tasks, which can be monitored either by timing or by some indirect measurement of the success of the execution. The aim of the present research is then to provide new means of measurements to be used for gaining objective information on the motion particularly of "non visible" joints like the shoulder complex in order to characterise properly their motion and, in turn, the workspace of the arm.