Sanchez-Lara Pedro A, Graham John M, Hing Anne V, Lee John, Cunningham Michael
Medical Genetics Institute, Cedars-Sinai Medical Center, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
Am J Med Genet A. 2007 Dec 15;143A(24):3243-51. doi: 10.1002/ajmg.a.32073.
Wormian bones are accessory bones that occur within cranial suture and fontanelles, most commonly within the posterior sutures. They occur more frequently in disorders that have reduced cranial ossification, hypotonia or decreased movement, thereby resulting in deformational brachycephaly. The frequency and location of wormian bones varies with the type and severity of cranial deformation practiced by ancient cultures. We considered the hypothesis that the pathogenesis of wormian bones may be due to environmental variations in dural strain within open sutures and fontanelles. In order to explore this further, we measured the cephalic index (CI) in 20 purposefully deformed pre-Columbian skulls: 10 from Chichen Itza, Mexico, and 10 from Ancon, Peru, as well as 20 anatomically normal skulls used for medical school anatomy classes. We tested for a direct correlation between the CI and the number of wormian bones in skulls with varying degrees of brachycephalic cranial deformation and found no significant correlation. When the CI was grouped into three categories (normal (CI < 81), brachycephalic (CI 81-93), and severely brachycephalic (CI > 93)) there was a trend toward increasing number of wormian bones as the skull became more brachycephalic (P = 0.039). A second part or our study tabulated the frequency and location of large wormian bones (greater than 1 cm) in 3-dimentional computerized tomography (3D-CT) scans from 207 cases of craniosynostosis and compared these data with published data on 485 normal dry skulls from a manuscript on wormian bones by Parker in 1905. Among cases of craniosynostosis, large wormian bones were significantly more frequent (117 out of 207 3D-CT scans) than in dry skulls (131 out of 485). There was a 3.5 greater odds of developing a wormian bone with premature suture closure (P < 0.001). Midline synostosis, specifically metopic or sagittal synostosis, has more wormian bones in the midline, whereas unilateral lambdoidal or coronal synostosis more often had wormian bones on the contralateral side. Taken together, these data suggest that wormian bones may arise as a consequence of mechanical factors that spread sutures apart and affect dural strain within sutures and fontanelles.
缝间骨是出现在颅缝和囟门内的附属骨，最常见于后颅缝。它们在颅骨骨化减少、肌张力减退或活动减少从而导致变形性短头畸形的疾病中更常见。缝间骨的出现频率和位置因古代文化所施行的颅骨变形类型和严重程度而异。我们考虑了这样一种假说，即缝间骨的发病机制可能是由于开放颅缝和囟门内硬脑膜应变的环境变化。为了进一步探究这一点，我们测量了20个有意变形的前哥伦布时期颅骨的头指数（CI）：10个来自墨西哥奇琴伊察，10个来自秘鲁安孔，以及20个用于医学院解剖学课程的解剖学正常颅骨。我们测试了不同程度短头畸形颅骨的CI与缝间骨数量之间的直接相关性，未发现显著相关性。当将CI分为三类（正常（CI < 81）、短头畸形（CI 81 - 93）和严重短头畸形（CI > 93））时，随着颅骨变得更加短头畸形，缝间骨数量有增加趋势（P = 0.039）。我们研究的第二部分列出了207例颅缝早闭的三维计算机断层扫描（3D - CT）中大型缝间骨（大于1厘米）的出现频率和位置，并将这些数据与1905年帕克关于缝间骨的一篇手稿中485个正常干燥颅骨的已发表数据进行比较。在颅缝早闭病例中，大型缝间骨明显比干燥颅骨更常见（207例3D - CT扫描中有117例）（485例中有131例）。过早缝合导致出现缝间骨的几率高出3.5倍（P < 0.001）。中线早闭，特别是额缝或矢状缝早闭，中线处缝间骨更多，而单侧人字缝或冠状缝早闭时，对侧更常出现缝间骨。综合来看，这些数据表明缝间骨可能是由于机械因素导致颅缝分开并影响颅缝和囟门内硬脑膜应变而产生的。
