Developmental Ossification Patterns in the Human Sternum from Fetus to 19 Years of Age: A Cross Sectional Study Based on Radiographic Analysis

The developmental ossification patterns in the sternal radiographs of 479 autopsy cases were analyzed in an attempt to determine the variation of ossification patterns in relation to age, sex and race. This study population consisted of 302 fetuses or newborns ranging in gestational age from 18 to 38 weeks, and 177 children or subadults ranging in age from 1 month to 19 years of age. Examination of the sternal radiographs revealed that the number and patterning of ossification centers in the sternum varied with age.

Variation in ossification patterning was found to be greatest during pre-natal and early post-natal development. Also with the increase of age, the mean number of ossification centers in the sternum increased. This increase in the number of ossification centers continued up to approximately 140 weeks after birth, after which there was a leveling due to fusion of adjacent centers. Also observed in this study were various sternal anamolies, primarily pre-mature ossification and fusion.

Statistical analysis of age, sex and race differences in the number of ossification centers in the sternum revealed variation as to age and sex. It was found that during early sternal development (18 weeks gestation to 140 weeks post birth) the mean number of ossification centers was greater in males than in females. Racial variation in the number of ossification centers, was found not to be statistically significant.

Application of this data can be used to up-date present anatomical literature concerning the development of the sternum. The findings pertaining to the sex differences in the developing sternum may provide an insight to sexual dimorphism in the adult sternum in future research.