Shoulder joint kinematics during elevation measured by ultrasound-based measuring system.

In order to analyze shoulder joint movements, the authors use a ZEBRIS CMS-HS ultrasound-based movement analysis system. In essence, the measurement involves the determination of the spatial position of the 16 anatomical points, which are specified on the basis of the coordinates of ultrasound-based triplets positioned on the upper limb, the scapula, and the thorax; their spatial position is measured in the course of motion. Kinematic characteristics of 74 shoulder joints of 50 healthy persons were identified during elevation in the plane of the scapula. Kinematic characteristics of motion were identified by scapulothoracic, glenohumeral, and humeral elevation angles; range of angles; scapulothoracis and glenohumeral rhythm; scapulothoracic, glenohumeral, and scapuloglenoid ratios; and the relative displacement between the rotation centers of the humerus and the scapula. Motion of the humerus and the scapula relative to each other was characterized by their rotation as well as the relative displacement between the rotation centers of scapula and humerus. The biomechanical model of the shoulder joint during elevation can be described by analyzing the results of the measurements performed.