Bilateral Fingerprint and Toeprint Ridge Characteristics among Ijaw and Ibibio Adults in Southern Nigeria: A Descriptive Cross-Sectional Study

Background: Bilateral friction-ridge measurements may provide descriptive information about digit-specific variation, but population-specific data that include both fingers and toes remain limited for adults from the Niger Delta region of Nigeria. Objective: To describe left- and right-sided fingerprint and toeprint ridge-count means and image-derived ridge-density measures separately in Ijaw and Ibibio adult samples. Methods: A community-based cross-sectional sample comprised 565 participants aged 18–40 years: 250 Ijaw adults (120 males and 130 females) and 315 Ibibio adults (150 males and 165 females). Bilateral impressions were acquired using a flatbed scanner and examined digitally. For each sex-by-population subgroup, mean values for corresponding digits and arithmetic left-minus-right mean differences were summarised. Results: The largest displayed fingerprint ridge-count difference was in the Ijaw male thumbs (left 12.52; right 14.81; difference −2.29 ridges). Ibibio male little-finger ridge counts were 13.16 on the left and 14.62 on the right (difference −1.46). In contrast, the corresponding mean index-finger density indices among Ibibio males were 14.13 and 14.38, respectively (difference −0.25). Toeprint mean differences were generally smaller than the largest finger ridge-count differences, although their size varied by digit and subgroup. Conclusions: These descriptive summaries document digit-specific left–right variation in the examined samples. Without calibrated ridge-density measurement and participant-level paired-difference analysis, the observations do not establish equivalence, statistical asymmetry, between-population contrasts, or identification performance.