A New Ultrasonographic Method for Forensic Age Estimation: Distal Ulna Epiphysis and Sesamoid Bone Analysis

Aim: Forensic age estimation plays a crucial role in various criminal and civil law contexts. In present study, we evaluated a cohort of 107 female and 109 male, aged 4 to 21 years. Ultrasonographic (USG) assessments were conducted on the sesamoid bone of the first metacarpophalangeal (MCP) joint and the distal epiphysis of the ulna. Material and Methods: We developed a USG staging system for the distal ulna comprising six stages, as well as criteria to determine the ossification of the sesamoid bone. Results: Notably, Stage 5 of the ulna epiphysis was absent in all individuals under 12 years of age, while Stage 6 was not observed in any individual under 15 years. In male, the earliest appearances of stages 2 through 6 occurred at ages 6.4, 8.2, 9.5, 13.8, and 17.2 years, respectively. For female, the earliest appearances of the same stages were noted at ages 4.7, 7.5, 8.6, 12.0, and 15.2 years, respectively. The inter-rater reliability for the ulna measurements demonstrated a high level of agreement (ICC=0.941, p<0.001), while the agreement for the sesamoid bone was substantial (Kappa=0.784) between the two researchers. Conclusion: These findings could provide a valuable tool for distinguishing between age groups pertinent to forensic age estimation. Specifically, stage 5 may serve as a quick test to verify that an individual is older than 12 years, while stage 6 could be utilized to indicate that an individual is over 15 years. Moreover, this method could function as a supplementary analytical tool within age estimation procedures.