Preliminary evaluation of palmar tri-radii-related measurements for sex estimation in an Arabian Gulf population sample

This cross-sectional study assessed the utility of the distance between palmar tri-radii for sex estimation in an Arabian Gulf population. We enrolled 125 citizens of the Arabian Gulf residing in Alexandria Governorate, Egypt, aged 18-30 years. The palmprints were obtained using fingerprint ink strips. Software (AutoCAD 2025) was used to analyze the 600 dots per inch (dpi)-scanned images of the inked palmprints. We investigated five palmar tri-radii present at the base of the fingers (a, b, c, d) and axial tri-radius 't' situated near the base of the fourth metacarpal. Four distances were measured, including the a-t, b-t, c-t, and d-t distances. Combined abcd-t distance was calculated for each palmprint. With excellent intra- and interobserver agreement, the measured variables exhibited significant sexual dimorphism, with males having larger values. Sex could be predicted from individual measurements, with modest performance. The most significant sex-predictive model incorporated bilateral palmprint measurements: log-odds of being male =-7.710 + 1.074 × (Right d-t) - 0.946 × (Right b-t) + 0.774× (Left a-t) + 0.590 × (Left c-t) - 0.334 × (Left d-t). The model achieved 82.7% sensitivity and an area under the curve of 76.2%. The palmar tri-radii-related measurements could guide sex estimation, alongside other evidence.