The distal femoral epiphysis used as a fetal maturity marker: Implications of extant medical data for bioarcheological analysis

The distal epiphysis of the femur is classically reported as a marker of fetal maturity and is thus identified in a bioarcheological context as an indicator that an individual died at or around the time of birth; it thus provides crucial information in the creation of the biological profile and associated burial practices. The aim of the present study was to re-evaluate this use by investigating an extant sample to assess (i) the age-related frequencies of both distal femoral and proximal tibial epiphyses and (ii) the influence of factors such as sex, vitality, and morbidity on the maturation of both epiphyses. The study was conducted on medical CT scans acquired in utero and ex utero between 2008 and 2017 in the hospital of Marseille (France). The final sample included 248 individuals aged between 26 and 42 completed gestational weeks (GW). Based on the results obtained in this study, 11% of the individuals from the sample aged between 26 and 33 completed GW had already developed a distal femoral epiphysis, whereas individuals aged between 38 and 42 GW had already developed both femoral and tibial epiphyses. According to these observations and current obstetrical practice, this maturation indicator cannot therefore be considered a precise estimator of whether a fetus is at term or not in an archeological context. Similarly, no delayed ossification was found among individuals who did not survive to 42 GW, or among those with severe developmental abnormalities, which does not support the hypothesis that delayed epiphysis maturation of the distal femur may be a morbidity marker for this age group in past populations.