Variations in count and width of the human middle phalangeal hair: A microscopic study
The aim of the present pilot study was to analyze human middle phalangeal hair (MPH) size at a microscopic level and to study relationships between MPH and prenatal androgens through a statistical combination with a 2D:4D ratio, which have not been studied so far.
The pilot sample consisting of 28 volunteers (16 males) was subjected to hand scans, counting their MPH numbers and collecting hair samples. The MPH widths were measured at the microscopic level, and their variations related to sex, body side, ﬁnger and the 2D:4D ratio, as measured based on the hand scans, were studied by means of a linear mixed-effects model.
In the 3rd and the 4th ﬁngers, we found signiﬁcant sex differences with higher counts in males, and signiﬁcant asymmetry in the counts in males with higher counts on the 4th right ﬁnger. Males had wider MPH shafts than females. In both sexes, signiﬁcantly wider hair shafts were found on the 4th ﬁnger compared with the 2nd ﬁnger. No signiﬁcant relationship was found between MPH shaft width and the 2D:4D ratio.
The present study found that MPH shaft width was signiﬁcantly different between the sexes and between the 2nd and 4th ﬁngers of both hands.