Three-dimensional kinematics of glenohumeral elevation

A three-dimensional magnetic field monitoring system (3Space$UNK Isotrak$UNK) was used on four fresh cadaveric shoulders to ascertain the plane of maximal humeral elevation and influence of humeral rotation on elevation referable to the scapula. With the source placed near the fixed scapula and sensor on the humeral shaft, a constant load was applied to the humerus affecting elevation in a range of planes anterior and posterior to the scapula. This is the first study to define the plane of maximal humeral elevation and quantitate the interrelationship of elevation with rotation. Without adequate humeral rotation, maximal elevation is impossible. These findings have significance for shoulder examination, rehabilitation, and selection of operative procedures that may limit humeral rotation resulting in a reduction of maximal elevation.