抄録
In order to make clear the movement of the carpal bones during active flexion-extension and radial-ulnar deviation of the wrist, a cineradiographic analysis of 60 normal wrists of 30 normal volunteers was carried out. The forearm was fixed in the neutral position with a specially- designed supporting device.
The radio-lunate angle, radio-scaphoid angle and scapho-lunate angle were all measured during flexion-extension of the wrist in the lateral view. The radio-lunate angle showed a large change in the first half of flexion and extension of the wrist from the neutral position to the maximal flexion and extension. The same tendency was observed in the radio-scaphoid angle.
In the antero-posterior view, the lunate angle formed by the ulnar tangent line of the lunate and the longitudinal axis of the radius, the perpendicular distance from the ulnar edge of the lunate to the line parallel to the longitudinal axis of the radius at the ulnar edge of the radius, and the height of the scaphoid were measured, respectively. When the wrist deviated from the radial side to the ulnar side, the height of the scaphoid increased in accordance with the dorsal flexion of the scaphoid. While the lunate was found only to slightly flex ulnarly in the same position from the radial deviation to about 20° of the ulnar deviation of the wrist, the lunate not only flexed ulnarly but slide radially in the remaining ulnar deviation.
The center of rotation described by Youm was also examined and the following result was obtained: The center of rotation existed from maximal radial deviation to 20°of the ulnar deviation. However, in maximal ulnar deviation, the center of rotation moved to the radio-distal direction, coordinating with the radial slide of the lunate bone.
Many authors have reported kinesiological analyses of the wrist based on various methods. Nevertheless, there has been controversy concerning the angular contribution of each carpal row to the total arc of the flexion-extension of the wrist. From our analysis, the mid-carpal joint had a share of 53% during flexion-extension and 59% during radial-ulnar deviation of the wrist, respectively.
Cineradiographic analysis was also made on a representative case with dynamic abnormality of the carpal alignment, showing the usefulness of cineradiography.
