Moscow University
Anthropology
Bulletin
Anthropology
Bulletin
1) Human Anatomy Dept. of the Medical Faculty of Ulyanovsk State University; 2) Applied Mathematics Dept. of the Mathematics and Information Technology Faculty of Ulyanovsk State University
Khayrullin R.M., e-mail: prof.khayrullin@gmail.com; Filippova E.N., e-mail: anat@ulsu.ru; Butov A.A., e-mail: pm@ulsu.ru; Kasterina A.V., e-mail: anat@ulsu.ru; Khayrullin F.R., e-mail: pm@ulsu.ru; Zerkalova Y.F., e-mail: anat@ulsu.ru
Introduction: 2:4 Digit ratio or Manning index (MI), the ratio between the length of index and ring fingers as the original morphometric parameters of human hand, according to some views, correlated with the level of prenatal testosterone levels, programming, along with the length of the fingers to the development of the brain and related behaviors. A number of studies allowed an uncritical interpretation of the variability is not completely unambiguous in fact this morphometric parameter. This casts doubt on the diagnostic value of the average values of the index in different groups of people. The purpose of this study was the values of MI in 477 males aged 15-49 years, homogeneous in ethnic composition, the territory of residence, social and gender characteristics of the left and right hand. From these results it follows that the dispersion of the resulting variability in the length of the ring finger as the own side or as the opposite side is much lower than its dispersion, due to variability in the length of the index finger. The overall variability of MI to a greater depends on the length of the index finger, rather than anonymous finger, despite the large absolute length of the latter. Over 60% of variability of index finger lengths is due to the correlative variation of ring finger length and vice versa. Varying component is small in value in 10% (+5% to -5%) of the MI in 80% of persons with the difference in the length of the fingers of no more than 4 mm. Accordingly, the authors believe that the average value of the index can be adequately replaced by constant values of equations of the linear dependence obtained by the method of graphic models of smoothing the surface. For the left hand, it is 0.973 for the right hand – 0.988. It is shown that the membership of the different hand types, ulnar (male) or radial (feminine), determines only about 30% of the variance of MI. The authors believe that the growth of bones in both pre-and postnatal development, is determined not only and not the level of prenatal or postnatal testosterone, it is known that the invariant growth of hand bones, especially the middle and distal phalanges, goes to men 70–79 years of age. Thus, the growth of tubular bones of the hand uneven across its rays throughout ontogeny can cause significant fluctuations in the values ??of different morphometric indices, including MI. Conclusion: legitimacy of reliable judgments about the level of prenatal testosterone and the degree of masculinization effects on fetal brain the digit ratio of the length of the definitive structure of the body, which has its own patterns of quantitative age dynamics throughout ontogeny unlikely. It can lead only to long-known in the morphology and physiology of human and animal phenomenon – the correlation of associative characteristics.
hand morphology, fingers biometry, digit ratio, bio-information models
Цит.: Khayrullin R.M., Filippova E.N., Butov A.A., Kasterina A.V., Khayrullin F.R., Zerkalova Y.F. Linear dependence of male 2D:4D digit ratio values // Moscow University Anthropology Bulletin (Vestnik Moskovskogo Universiteta. Seria XXIII. Antropologia), 2011; 2/2011; с. 16-24
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