Patterns of variability of the shape of the human hand

Abstract

The differences between the hands of men and women are mainly observed in the difference in the ratio of the lengths of the index and ring fingers (ratio 2d:4d) or in the difference in the proportional ratios of longitudinal and transverse dimensions, identified using classical morphometry methods, which give only indirect ideas about variations in the shape of the hand. The object of this study was digital images of radiographs of the right hands of 50 men and 50 women, on which 20 landmarks were located, the configuration and two-dimensional coordinates of which were studied using geometric morphometry methods. The predominance of the general variability of the hand’s shape was associated with a combined multidirectional transformation in the space of the elements of the II-V rays of the hand relative to the longitudinal axis with simultaneous compression or stretching of the shape relative to the transverse axis. At the same time, men have a stretching of the shape of the hand from the IV-V rays and compression from the II-III rays, while women have reverse changes. The relationship between the shape and size of the hand, regardless of gender, is minimal – 5.82% and 3.93% of hand allometry were detected in men and women, respectively. This study shows that the shape of the hand is markedly different in men and women, which indicates a significant sexual dimorphism affecting this trait. Based on the detected sexual differences, it is possible to distinguish the male and female morphological type of the hands.