Sternum length norms in Han youngsters in central China

The sternum is one of the most important components of the chest wall. However, to the best of our knowledge, at present there is no reference value of the sternum length in normal Han Chinese children that has been published in the literature. The aim of the present study was therefore to establish the reference value of sternum length in a normal Han Chinese population of different ages and sex groups. Chest computed tomography scans and three-dimensional reconstruction images of 1,080 individuals who were younger than 18 years old and without congenital or acquired structural anomalies or congenital metabolic diseases were retrospectively reviewed. The length of the sternum was measured for each individual and comparisons of the sternum length according to sex were conducted using the Mann-Whitney test. Age or region group comparisons were performed using the ANOVA test, and the association between the length of the sternum and age was assessed by regression analysis. A significant association between the age (x) of the individual and the length of the sternum (y) was confirmed, although different regression patterns were identified for the sexes (the regression equation for males was y=5.616x+60.408; P<0.001; R(2)=0.890, whereas that for females was y=-0.134x(2)+6.543x+56.805; P<0.001, R(2)=0.890). No significant differences in sternum length were identified between the sexes for subjects aged 1-13 years old, whereas significant differences were observed comparing the sexes of the subjects aged 14-18 years old. In conclusion, the present study revealed that the length of the sternum in normal Han Chinese children can be precisely estimated by the age of the child using our formulae for the different sexes (where the most-fit formulae for the two sexes are different). This knowledge can be applied clinically in chest wall deformity assessment, and in surgery planning.