Purpose: To determine whether the grip of a healthy subject's hand shows certain universal characteristics. To accomplish this, we examined the complex interactions of the fingers during gripping of different-size cylindrical objects.
Methods: A total of 48 subjects (11 women, 37 men) performed 5 cylinder grips with different object sizes. The 14 joint angular profiles of the 5 digits were measured dynamically with a Technische Universität Berlin sensor glove.
Results: Frequently, initial movement was detected before the actual grip. This movement consisted of passive flexion of the fingers the moment the hand rose from the table, followed by active extension of the fingers before gripping the object. Along with the type of joint, the size of the object gripped influenced the frequency of these initial movements (p<.001). During actual grip, the proximal interphalangeal joints' flexion was significantly greater than the flexion of the metacarpophalangeal and distal interphalangeal joints (p<.001). The mean flexion of the proximal interphalangeal joints was 43 degrees , that of the metacarpophalangeal joints was 28 degrees , and that of the distal interphalangeal joints was 26 degrees. Apart from these findings, the larger the flexion angle was, the more time tended to be needed to fulfil the motion.
Conclusions: The results show that there is a universal motion pattern with the cylinder grip in healthy individuals concerning the range of movement of the finger joints. However, to fully understand the cylinder grip in healthy individuals, our next step will be to analyze the dynamics of the cylinder grip as well. For that purpose, we examine the dynamic interactions between the fingers--that is, their chronological sequence during the cylinder grip.
Copyright 2010 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.