Document Type



Principal components analysis using radial and ulnar digital ridge counts was performed using a sample of 167 male and 196 female unrelated White Americans from Southwestern Ohio. Components representing three regions separately for radial and ulnar ridge counts were obtained in a terminal solution, following varimax rotation. The relationships, consistent across sex and hand; suggest the presence of three distinct digital regions; digit I, digits II and III, and digits IV and V. Hypotheses relating to “developmental fields” and “volar pad distorting forces” in the development of dermal ridges are brought together and discussed in light of the reported findings. The digital regions identified are considered to correspond to underlying developmental fields providing differing local environments that interact with a gene set specifically involved with the formation of volar pads and dermal ridges.