Second to Fourth Digit Ratio(2D:4D) in North-West Indians: Sexual Dimorphism

Abstract

The index (2D) to ring finger (4D) ratio less than one (2D:4D < 1) has been considered as a “male finger pattern” and 2D:4D more than or equal to one (2D:4D≥1) has been considered as a “female finger pattern”. The present study was conducted on 100 young adults (m=56, f=44) from northwest population of India to find out the sexual dimorphism and right-left asymmetry in WAD ratio by three different methods namely visual, direct and scan methods. Visual method showed that significantly more number of males were having Type 3 hand i.e. index finger smaller than ring finger compared to females who more often had Type 1 hand i.e. index finger longer than ring finger (p< 0.001). The mean 2D:4D ratios in males were observed to be 0.97 by direct method and 0.96 by scan method. In females the ratio was 1.00 and 0.99 by direct and scan methods respectively; sex difference being statistically significant (p <0.001).Mean values by direct method were slightly higher than scan method but the difference was statistically insignificant. In both sexes there was no significant right left asymmetry.