SUTURAL BONE FREQUENCY IN SYNOSTOTIC RABBIT CRANIA

This study tests the hypothesis that crania with synostosed sutures wi ll have a significantly higher incidence of calvarial sutural bones th an normal crania. Sutural bones were counted in seven calvarial suture s and compared among four groups of adult New Zealand white rabbit sku lls: normal in-colony (NI) controls (N = 14), normal out-colony (NO) c ontrols (N = 12), skulls with familial delayed onset (DO) coronal syno stosis (N = 25), and skulls with experimentally immobilized coronal su tures (EI) (N = 20). Comparisons among groups were made with a Kruskal -Wallis one-way ANOVA and between groups with a Mann-Whitney U-test, u sing a Bonferroni correction for multiple comparisons. Significant dif ferences (P < 0.05) were noted only in the coronal and sagittal suture s, with EI crania having the greatest number of coronal sutural bones; between group differences were undetectable for sagittal sutural bone s. A post hoc two-sample binomial test for equal proportions showed th at the distribution of coronal sutural bones among individuals across groups was even, while the distribution of sagittal sutural bones was significantly higher in FI crania. These results suggest that altered sutural forces of the calvaria contribute to an increased occurrence o f sutural bones. However, the influence of inheritance on increased oc currence of sutural bones cannot be discounted, as reflected in the eq uivalent number of individuals across groups that possessed coronal su tural bones. (C) 1997 Wiley-Liss, Inc.