"Missing" Sternal Ossification Center: Potential Mimicker of Disease in Young Children

Purpose: To evaluate the frequency of "missing" sternal ossification center (asynchronous non-ossification) in young children.

Materials And Methods: Lateral chest radiographs obtained in 229 children (mean age, 3.7 years) were retrospectively evaluated for sternal ossification. Four superior sternal segments were considered normal if they were ossified to a similar degree. A segment was considered asynchronous if decreased ossification, as compared with the remaining sternal segments, was demonstrated or if ossification was absent. Asynchronous ossification of inferior sternal segment 5 was recorded separately. Logistic regression analysis was applied to determine if there was a statistically significant relationship (P <.05) between age or sex and pattern of sternal ossification (normal vs asynchronous).

Results: Of the 916 superior four sternal segments (four segments in each of 229 patients) evaluated, 32 (3.5%) showed asynchronously decreased or absent ossification. Locations of these 32 segments follow: segment 1, two (0.2%) instances; segment 2, 14 (1.5%) instances; segment 3, two (0.2%) instances; and segment 4, 14 (1.5%) instances. Inferior segment 5 was not ossified in 73 (31.9%) patients. There was a statistically significant relationship between decreased age and increased likelihood of occurrence of asynchronous ossification of one of the sternal ossification centers 1-4 (P >.003) and of occurrence of asynchronous ossification at sternal segment 2 (P <.018).

Conclusion: Missing sternal ossification centers occur most commonly at segments 2 and 4. Such asynchronous non-ossifications become less common in older children.