Bone cortical mass in newborn infants: a comparison between standards in the femur and humerus.

The total bone width (T) and medullary width (M) of the humerus and femur of 216 and 138 Nigerian newborn infants, respectively, were measured in order to determine the normal standards for cortical bone mass in the newborn. The cortical width (C), cortical area (CA), and percentage cortical area (PCA) were calculated for each bone and correlated with gestational age and birth weight. In both the femur and humerus, the values of the cortical measurements were higher in males. The strongest correlation coefficients were obtained between T(0.84), C(0.79), and CA(0.84) and birth weight in the humerus. The correlation with gestational age was, however, similar in both bones. The values of humeral cortical width (C) obtained in this study is less than had been reported in North American white newborn infants. Cortical measurements of the humerus, which is invariably included in the newborn chest radiograph, is a more reliable method of evaluating the status of bone mineralisation than the femur.