Topological variability of fingerprint ridge density in a sub-Saharan population sample for application in personal identification.

Variability in ridge density in a sub-Saharan population sample was studied by counting ridges in three fingerprint areas (two distal regions, radial and ulnar, and one proximal region) on the epidermal surface of the distal phalanx. Study material was obtained from the fingerprint impressions of 100 male sub-Saharan subjects aged between 18- and 48-years old. The results were compared with those obtained from a Spanish population sample. Sub-Saharan males presented lower ridge density than Spanish males in the distal regions (radial and ulnar) of all fingers, whereas differences in the proximal region were only observed on some fingers. Using the differences observed between these populations, the likelihood ratio for inferring membership of one of the populations from a fingerprint of unknown origin was calculated; therefore, a ridge density of 14 or less for both areas (ulnar and radial), support an origin sub-Saharan versus Spanish population.