Scaphoid and lunate movement in different ranges of carpal radioulnar deviation.
OBJECTIVE
We aimed to investigate scaphoid and lunate movement in radial deviation and in slight and moderate ulnar deviation ranges in vivo.


METHODS
We obtained computed tomography scans of the right wrists from 20° radial deviation to 40° ulnar deviation in 20° increments in 6 volunteers. The 3-dimensional bony structures of the wrist, including the distal radius and ulna, were reconstructed with customized software. The changes in position of the scaphoid and lunate along flexion-extension motion (FEM), radioulnar deviation (RUD), and supination-pronation axes in 3 parts--radial deviation and slight and moderate ulnar deviation--of the carpal RUD were calculated and analyzed.


RESULTS
During carpal RUD, scaphoid and lunate motion along 3 axes--FEM, RUD, and supination-pronation--were the greatest in the middle third of the measured RUD (from neutral position to 20° ulnar deviation) and the smallest in radial deviation. Scaphoid motion along the FEM, RUD, and supination-pronation axes in the middle third was about half that in the entire motion range. In the middle motion range, lunate movement along the FEM and RUD axes was also the greatest.


CONCLUSIONS
During carpal RUD, the greatest scaphoid and lunate movement occurs in the middle of the arc--slight ulnar deviation--which the wrist frequently adopts to accomplish major hand actions. At radial deviation, scaphoid and lunate motion is the smallest.
Department of Hand Surgery, Hand Surgery Research Center, Affiliated Hospital of Nantong University, Nantong, Jiangsu, China. jinbotang@yahoo.com
Jin Bo
JB
Tang
Jing
J
Xu
Ren Guo
RG
Xie
D000328:Adult; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D012667:Lunate Bone / Q000000981:diagnostic imaging / Q000502:physiology; D008297:Male; D009068:Movement / Q000502:physiology*; D019651:Plastic Surgery Procedures; D021361:Scaphoid Bone / Q000000981:diagnostic imaging / Q000502:physiology*; D014057:Tomography, X-Ray Computed; D014955:Wrist Joint / Q000000981:diagnostic imaging; D055815:Young Adult