Three-dimensional kinematic analysis of the second through fifth carpometacarpal joints

The kinematics of the 2nd through 5th carpometacarpal (CMC) joints was inve stigated by using a 3-dimensional dynamic motion analysis system to delinea te flexion-extension motion, radial-ulnar deviation, and pronation-supinati on motion. Analysis of the axes of rotation revealed that the axes of rotat ion for flexion-extension motion are located within the base of each respec tive metacarpal bone. The axis of rotation for radial-ulnar deviation passe s through the distal carpal bone of each CMC joint except in the 3rd CMC jo int where the axis of rotation is located within the base of the 3rd metaca rpal. The axis of rotation for pronation supination motion passes through t he base of the respective metacarpal except in the 3rd CMC joint where it i s located within the hamate. The overall flexion-extension motions of the 2 nd and 3rd carpometacarpal (CMC) joints were found to be more limited than those of the 4th and 5th CMC joints (11 degrees, 7 degrees to 20 degrees, 2 7 degrees, respectively) and even more so in radial-ulnar deviation (2 degr ees, 4 degrees to 7 degrees, 13 degrees, respectively) and pronation-supina tion motion (5 degrees, 5 degrees to 27 degrees, 22 degrees, respectively). The 5th CMC joint has the greatest overall range of motion with the flexio n-extension motion found to be greatly reduced by 40% to 28 degrees when th e 4th CMC joint was immobilized. Maximum range of motion in flexion-extensi on of the 5th CMC joint is dependent on and contributed by the 4th CMC join t motion. Copyright (C) 2001 by the American Society for Surgery of the Han d.