Roentgenographic cranial-base and calvarial measurements of Jamaican children between one month and five years.

Three-hundred-and-thirty lateral skull-films obtained from apparently healthy normocephalic Jamaican children between the age of one month and five years were studied, using bony reference points nasion (N), tuberculum sellae (Ts), internal occipital prominence (IOP), inion (I), bregma (B) and lambda (L). Cranial-base length was measured between N-Ts, Ts-IOP and N-I. Calvarial height was measured between Ts-B (anterior calvarium) and Ts-L (posterior calvarium). All the measurements showed an increase with age and were higher in boys. Significant correlations were seen between N-Ts and Ts-IOP, N-Ts and N-I, N-Ts and Ts-B, N-Ts and Ts-L and N-I and Ts-L at all the ages and in both sexes. Ratios between lengths of anterior and posterior cranial-base, as well as between cranial-base lengths and anterior cranial heights, were nearly constant at all the ages and in both sexes. These observations support the view that there is definite proportionality between the growth of anterior and posterior cranial-base lengths, and between anterior calvarial height and cranial-base lengths. On the other hand, a significant increase with age was seen in the ratios N-Ts/Ts-L, N-I/Ts/L and Ts/B/Ts-L, suggesting a progressive decrease in growth of posterior calvarial height. A comparison of the data with previously published figures for Indian and Norwegian populations suggests a racial difference in the various cranial-base and calvarial ratios.