The clavicle plays an important role for forensic age estimation in living individuals, particularly with regard to the age of majority. The present prospective study aims to evaluate the age-dependent ossification process of the medial clavicular epiphysis in order to establish the clavicular sub-stages introduced in 2010 as well as the advantages and possibilities of thin-slice computed tomography (CT). For this purpose, 0.6 mm thin-slice CT scans of sternoclavicular joints of 572 bodies aged between 10 and 40 years were evaluated by means of two complementary classification systems: a five-stage system and a sub-staging system for the main stages 2 and 3. Assessment was possible in 493 cases. The results for stages 4 and 5 are in line with previous studies that found the ages of 21 years and 26 years, respectively, as minimum ages for these stages. Sub-stage 3c was first found at the age of 19 years in both sexes, thereby corroborating the value of this sub-stage as to statements about the age of majority. In comparison to other CT studies, stage 3a was first observed ~1 year earlier (16.4 years in males and 15.5 years in females). Stage 2c only occurred in 3 cases. In conclusion, the data corroborate the significance of diagnosing sub-stages as well as the value of thin-slice CT. For forensic practice, the concomitant and complementary use of both classification systems applied in this study can be recommended.
