The hinge axis: evaluation of current arbitrary determination methods and a proposal for a new recording method.

A proposed arbitrary method of recording the hinge axis based on the correlation between the profile width of the face and the kinematic axis was compared with three commonly used arbitrary methods. The investigation was carried out on 51 individuals. The kinematic point was recorded by the use of a kinematic locator. The different points of emerging axes were photographed at a fixed distance by using a magnification photoapparatus. The proposed method showed a regular distribution around the kinematic axis. Furthermore, this method clearly illustrated that its highest concentration was in the posteriosuperior quarter around the true axis. The proposed technique was found to be more accurate than the other techniques.