Forensic age estimation by morphometric analysis of the manubrium from 3D MR images.

Forensic age estimation research based on skeletal structures focuses on patterns of growth and development using different bones. In this work, our aim was to study growth-related evolution of the manubrium in living adolescents and young adults using magnetic resonance imaging (MRI), which is an image acquisition modality that does not involve ionizing radiation. In a first step, individual manubrium and subject features were correlated with age, which confirmed a statistically significant change of manubrium volume (Mvol:p<0.01, R2¯=0.50) and surface area (Msur:p<0.01, R2¯=0.53) for the studied age range. Additionally, shapes of the manubria were for the first time investigated using principal component analysis. The decomposition of the data in principal components allowed to analyse the contribution of each component to total shape variation. With 13 principal components, ∼96% of shape variation could be described (Mshp:p<0.01, R2¯=0.60). Multiple linear regression analysis modelled the relationship between the statistically best correlated variables and age. Models including manubrium shape, volume or surface area divided by the height of the subject (Y∼MshpMsur/Sh:p<0.01, R2¯=0.71; Y∼MshpMvol/Sh:p<0.01, R2¯=0.72) presented a standard error of estimate of two years. In order to estimate the accuracy of these two manubrium-based age estimation models, cross validation experiments predicting age on held-out test sets were performed. Median absolute difference of predicted and known chronological age was 1.18 years for the best performing model (Y∼MshpMsur/Sh:p<0.01, Rp2=0.67). In conclusion, despite limitations in determining legal majority age, manubrium morphometry analysis presented statistically significant results for skeletal age estimation, which indicates that this bone structure may be considered as a new candidate in multi-factorial MRI-based age estimation.

Factors affecting the rate and pattern of the first costal cartilage ossification.

In the present study, the extent of costochondral ossification of the first rib was determined from 78 chest roentgenograms of 13 healthy male soldiers subjected to a periodic follow-up. Roentgenography was performed at a mean interval of 2.9 years over a 15-year period. Mean subject age was 24 years at the commencement of the study and 37 years at its termination. Our results show that ossification of the first costal cartilage may start early in adult life and progress at individual rates. The ossification process proceeded from the costal toward the sternal end of the cartilage in an anteromedial direction. The morphological age-related changes ranged from the formation of small osseous islands in the cartilage to a complete ossification between the first rib and the sternum. The main conclusion of the study is that the degree of ossification of the first costal cartilage as an indicator of age does not provide the precision necessary for anthropological or forensic studies.

Radiology of postnatal skeletal development. II. The manubrium and sternum.

Thirty-six manubriosternal composites from skeletally immature cadavers were examined morphologically and radiographically. Sternebral ossification followed certain patterns. The manubrium (first sternebra) usually had one primary ossification center and one or two smaller centers. These usually were caudad to the major center (longitudinally bifid). The second sternebra invariably had only one ossification center. The third and fourth sternebrae had latitudinal (right-left) bifid ossification centers, undoubtedly a result of the original formation of the sternum from two longitudinal mesenchymal anlagen. Occasionally the fourth sternebra exhibited longitudinally bifid ossification. The usual pattern was ossification of four sternebrae, although a fifth was intermittently present. The xiphisternum (not a true sternebra) was infrequently ossified.