Postnatal maturation of the sternum in a Portuguese skeletal sample: a variable ossification process

The timing of skeletal maturation is one of the common indicators used to estimate age at death of juvenile skeletal remains. Skeletal maturation of the sternum has received less attention than other anatomical locations, and there is a general lack of detailed information about the fusion timing in the dry sternum that can be used for the estimation of age. The objective of this study is to document the age variation in the fusion of the body sternebrae, and both clavicular and intercostal notches. A three stage scale scheme was used (unfused elements, partial, and complete fusion) to quantify fusion of primary and secondary ossification centres in a sample of 68 individuals of both sexes from the identified skeletal collection housed at the National Museum of Natural History and Science in Lisbon, Portugal. Analysis was performed only for the pooled sex sample due to small sample size. Wide age intervals were obtained for fusion stages at all of the sternal centres. Primary ossification centres start to fuse between 1 and 27 years of age, with sternebrae 3 and 4 completing their fusion first. Secondary ossification centres fuse between 5 to 25 years of age. Results reflect considerable variability among individuals in the maturation of the sternum.