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Cross‐sectional data on soft tissue morphometry of the growing hand and fingers of dextral individuals 5–65 years old
Author(s) -
Mayhew T. M.
Publication year - 2012
Publication title -
journal of anatomy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 118
eISSN - 1469-7580
pISSN - 0021-8782
DOI - 10.1111/j.1469-7580.2012.01553.x
Subject(s) - sexual dimorphism , sinistral and dextral , numerical digit , demography , anatomy , biology , mathematics , endocrinology , arithmetic , paleontology , tectonics , sociology
This study examines both hands of right‐handed (dextral) subjects 5–65 years old in order to define the separate growth trajectories of digit lengths (2 D –5 D ) and hand widths; to assess how 2 D : 4 D and other digit ratios also vary with age; and to test whether lengths are influenced by gender dimorphism and lateral (right/left) asymmetry. Calliper measurements were made from hand photocopies. Growth patterns were analysed by linear regression and correlation, main and interaction effects of age and gender were resolved by analysis of variance, and lateral asymmetries were identified by paired tests. All digits, and hand width, grew in a biphasic pattern in both hands, and inflection points between phases showed gender dimorphism. In the early fast‐growing phase, male digits grew over a longer period than those in females, before switching to a slower growth phase during which gender dimorphism became more exaggerated. In right hands, age differences in digit ratios were confined to 2 D : 4 D and, except for 4 D : 5 D , females tended to show larger ratios than males. In left hands, all ratios (except 3 D : 5 D ) varied with age and gender influenced only 2 D : 4 D , 2 D : 5 D and 3 D : 5 D . Again, ratios were greater in females. In females, 2 D was longer in the right hand of older subjects, whilst 3 D , 4 D and 5 D tended to be shorter in the right hand of younger subjects. No asymmetries were seen in 2 D , 3 D or 4 D in males, but 5 D tended to be shorter on the right in the group 9–12 years old. Finally, hand width tended to be greater in females on the right at 9–65 years old, and in males on the right at 18–23 years old. A further novel finding was that certain relationships (inflection points, correlation coefficients and gender differences in digit lengths) seemed to follow gradients running from 2 D to 5 D . It is tempting to speculate that these are manifestations of the antero‐posterior gradients established by signalling events that control digit development and patterning in utero .