Elements of a general theory of joints. 4. Coupled joints as simple gear systems.

Abstract

In the present article the relative motion in the horizontal plane of 2 adjacent lumbar vertebrae (axial rotation of the lumbar spine) and the cranial border movement of the mandible parallel to the vertical-sagittal plane are examined. The interplay of joints is depicted onto the function of a gear system with positive drive. The limits of this projection are described.