Relative motion of selected carpal bones: a kinematic analysis of the normal wrist.

The relative motion of selected carpal bones and the radius was studied using five cadaver specimens labeled with metal markers to precisely quantitate their motions. Data was obtained by means of a combination of orthoradiography, sonic digitization, and computer analysis. We conclude that the wrist functions as two carpal rows with the distal row bones relatively tightly bound to one another and the proximal row bones less so but still moving together. Therefore, we theorize that the proximal row functions as a variable geometry intercalated segment between the distal row and the radius-triangular fibrocartilage.