Digit ratio and laterality indices: the Chuvashian study
The aim of the present study was to evaluate the association between digit ratio indices (representing the prenatal androgen and estrogen exposure) and different laterality indices, handedness (HDD), the dominant eye (DE), hand clasping (HCL) and arm folding (ARMF) in a large (N=1,586) Chuvashian population-based sample.
HDD showed a significant association with the right phalangeal length ratio, the right and the left metacarpal ratio and the right ray ratio. Subjects with a right dominant hand had lower right phalangeal, right and left metacarpal and right ray ratios than those with a left dominant hand. This is the first study showing a significant association between the eye dominance and the left metacarpal and the left ray ratios. Subjects with a right DE had lower left metacarpal and left ray ratios than those with the left DE. HCL and ARMF showed no association with radiologically measured digit ratios.