An Ellipsoidal Representation of Human Hand Anthropometry

Abstract

The goal of this study was to collect anthropometric data that describe the geometry of the surface of the hand and to model this anthropometry as a function of gross external hand measurements. The depth and breadth of each segment of the hand were measured at points that were spaced at approximately equal distances between the joints of the hand. Linear models using hand breadth as the independent variable explained from 12% to 47% of the variation in segment breadths and from 6% to 74% in segment depths. Ellipsoids are used in biomechanical models as an efficient mathematical description of the shape of kinematic segments for use in the determination of contact with other objects. Therefore the primary objectives of this study were to approximate the semiaxis dimensions for these hand segment contact bodies using a linear model of the gross anthropometry and to evaluate the accuracy with which ellipsoids describe the geometry of the hand segments. Graphical comparisons showed that differences between the ellipsoidal approximations and the breadth and depth measurements were largest near the joints. Data collected in this study could be used to create a set of overlapping ellipsoids that would provide a more accurate representation of hand geometry, and this representation could be adapted to biomechanical models that use ellipsoids to define segment geometry.