Forensic evaluation of sex estimation via measurements of adult index and ring finger lengths using postmortem computed tomography

Abstract

Background: Sex estimation from fragmented or isolated human bones found during excavations is imperative not only in the field of forensics but also paleoanthropology. This study investigated the possibility of sex estimation from computed tomography (CT) data for the lengths of the index and ring fingers. The scans were obtained using a multislice ECLOS-16 CT scanner (Hitachi Medical Co., Tokyo, Japan), and the images were analyzed using a SYNAPSE VINCENT volume analyzer (Fujifilm Medical Co., Tokyo, Japan). For 205 cases, the authors measured the total length of the distal, middle, and proximal phalanges (P) and of the metacarpal bones for the index and ring fingers of both hands. Right heart serum testosterone and estradiol levels in 92 cases were also measured by an electrochemiluminescence immunoassay and a chemiluminescence immunoassay, respectively. Result: The difference in P between the index and ring fingers was significantly greater in men than in women for both hands; receiver operating characteristic analysis showed an optimal cutoff of 6.0 mm (sensitivity, 0.64 and specificity, 0.64). Blood testosterone levels were moderately correlated with this difference. Conclusion: A value of 6.0 mm for the ring finger–index finger difference for the left hand distinguished men from women, and these results are affected by testosterone levels. The findings from this report in the field of forensics and paleoanthropology indicated that the CT data-assessed morphometry of the phalanges could be used as an objective index for sex estimation.