Sternal Development in the Pediatric Population: Evaluation Using Computed Tomography

Background: The normal development of the sternum using CT imaging is not known.

Objective: To describe the normal development of the sternum in children on chest CT imaging.

Materials And Methods: CT imaging of 300 patients (150 male, 150 female), mean age: 4.97 years (range: 0.01-9.9 years), were evaluated retrospectively. The presence and number of ossification centers in the manubrium, each individual mesosternal segment and the xiphoid were reviewed. Additionally, the vertical and horizontal fusion between ossification centers was evaluated. Differences among age and gender were calculated. Descriptive statistics, analysis of variances (ANOVA), chi-square and Fisher exact tests were performed for statistical analysis.

Results: Manubrium: A single ossification center was seen in 88% of cases and two or three ossification centers were seen in 12%. More manubrial ossification centers were correlated to a younger age (P < 0.001, R = -0.2). Mesosternum: Majority of patients had a single ossification center in the first segment (85%). The majority of patients had double ossification centers in the second and third segments (51% and 64%, respectively). No ossification center was seen in the fourth segment in 38% of patients. No significant difference among the age of vertical ossification between mesosternal segments was found. (ANOVA; P > 0.05). Xiphoid: Absence was seen in 67% of the patients. Bifid xiphoid was seen in 1% of the patients.

Conclusion: The normal development of the different components of the sternum is a process with wide variation among children. The large variability of mesosternal ossification center types should not be confused with pathology.