Sutural bone frequency in synostotic rabbit crania

Abstract

This study tests the hypothesis that crania with synostosed sutures will have a significantly higher incidence of calvarial sutural bones than normal crania. Sutural bones were counted in seven calvarial sutures and compared among four groups of adult New Zealand white rabbit skulls: normal in-colony (NI) controls (N = 14), normal out-colony (NO) controls (N = 12), skulls with familial delayed onset (DO) coronal synostosis (N = 25), and skulls with experimentally immobilized coronal sutures (EI) (N = 20). Comparisons among groups were made with a Kruskal-Wallis one-way ANOVA and between groups with a Mann-Whitney U-test, using a Bonferroni correction for multiple comparisons. Significant differences (P < 0.05) were noted only in the coronal and sagittal sutures, with EI crania having the greatest number of coronal sutural bones; between group differences were undetectable for sagittal sutural bones. A post hoc two-sample binomial test for equal proportions showed that the distribution of coronal sutural bones among individuals across groups was even, while the distribution of sagittal sutural bones was significantly higher in EI crania. These results suggest that altered sutural forces of the calvaria contribute to an increased occurrence of sutural bones. However, the influence of inheritance on increased occurrence of sutural bones cannot be discounted, as reflected in the equivalent number of individuals across groups that possessed coronal sutural bones.

The Incidence and Topographic Distribution of Sutures Including Wormian Bones in Human Skulls

“…10 The external mechanical factors that increase the sutural width and dural strain may cause the formation the WBs. 15 WBs are usually found in lambdoid sutures, followed by coronal, sagittal, and metopic sutures. In the present study, the sutures including WBs were determined in descending order of frequencies: lambdoid, pterion, asterion, squamous, lambda, sagittal, coronal, occipitomastoid, and bregma.…”

Rescue of coronal suture fusion using transforming growth factor‐beta 3 (Tgf‐β3) in rabbits with delayed‐onset craniosynostosis

“…It is thought that this continuum ranges from 1) normal growing sutures in affected genotypes on one end to 2) delayed-onset and single-suture synostosis in the middle of the continuum, and then to 3) early-onset and multiple-suture synostosis at the other extreme. Although the pathogenesis of delayed-onset synostosis is unknown, dense collagen bundles, small bony bridges, and an increased number of sutural bones have all been observed in the coronal sutures of rabbits with delayed-onset synostosis (Mooney et al, 1994a(Mooney et al, ,b, 1996aBurrows et al, 1995Burrows et al, , 1997Losken et al, 1998Losken et al, , 1999. These bundles, bridges, and supernumerary bones probably immobilize the suture and result in neurocranial growth restrictions and altered neurocapsular growth vectors, as observed in both the rabbit model (Mooney et al, 1994b;Burrows et al, 1995;Losken et al, 1998) and clinically (Reddy et al, 1990;Hoffman and Reddy, 1991;Cohen et al, 1993;Cohen and MacLean, 2000).…”

Mechanical Influences on Suture Development and Patency

“…Intrauterine constraint is usually considered as placing most sutures under compression [70,71]. Positional lambdoid suture plagiocephaly in humans may also be an example of quasi-static compression [72], as may artificial deformation of human or animal skulls, although in these cases compression at one suture may lead to tension at others [73,74]. The results of these disparate compression studies were essentially identical.…”