Sliwonik Iwona
Katedry i Zakładu Anatomii Prawidłowej Pomorskiej Akademii Medycznej w Szczecinie, al. Powstańców Wlkp. 72, 70-111 Szczecin.
Ann Acad Med Stetin. 2002;48:145-62.
Seventy-two parietal bones from human fetuses aged 15 to 29 weeks were studied. Three age groups were formed: I--15-19 weeks; II--19-24 weeks, III--25-29 weeks. The width and length of each parietal bone was determined. Microradiological studies were done with the Unipan 401 X-ray apparatus. Subsequently, pulverized bone for biochemical studies was prepared. Calcium, magnesium, zinc and iron content was determined using atomic spectrophotometry. Phosphates were measured with a colorimetric method and fluorine was assayed using an ion-selective electrode. The dimensions of fetal parietal bones changed almost linearly with age until the 20th week of life when a deceleration in the growth rate was noted (Tables 1, 2, 3, 4). This finding could be useful for estimation of fetal age when other methods are unavailable. The parietal bone is formed from one or two primary ossification centers lying in the same plane or one above the other (Figs. 1, 2, 3). Fusion of primary ossification centers was observed between 15 and 19 weeks of life (Fig. 3). Trabeculae radiate from the primary ossification center to the periphery of the parietal bone and take the form of a "coral reef" within the tuber (Figs. 2 and 5). Transverse ossification which was not coordinated with the growth of trabeculae from the primary ossification center was observed between week 15 and 19 of intrauterine life (Fig. 2). Fusion of peripheral trabeculae with those from the ossification center takes place at a later stage of osteogenesis (Fig. 4). Parietal bones of 29-week-old fetuses consisted of two layers of trabeculae and a distinct tuber, except for the sagittal and coronal sutures and the anterior fontanel, where a single layer of trabeculae was observed. Trabeculae were well developed and densely packed (Fig. 5). Analysis of the mineral composition of fetal parietal bones confirmed that the major elements are calcium and phosphorus and that their content increases with age (Figs. 6 and 7). Fluorine content differed widely and was unrelated to age (Fig. 9, Tab. 1). The importance of fluorine in the process of mineralization of parietal bones requires further study. Magnesium content increased with age (Fig. 8) and did not correlate with calcium or phosphorus. Apparently, these elements play different roles in the process of mineralization. The content of zinc and iron, two labile components of bone, decreased with age (Figs. 10 and 11). Some of these changes could have taken place during storage of the bones.
对72块来自15至29周龄人类胎儿的顶骨进行了研究。形成了三个年龄组：I组——15 - 19周；II组——19 - 24周；III组——25 - 29周。测定了每块顶骨的宽度和长度。使用Unipan 401 X射线设备进行了微放射学研究。随后，制备了用于生化研究的粉碎骨。使用原子分光光度法测定钙、镁、锌和铁的含量。用比色法测量磷酸盐，并用离子选择性电极测定氟。胎儿顶骨的尺寸在出生后第20周之前几乎随年龄呈线性变化，之后生长速率出现减速（表1、2、3、4）。当其他方法不可用时，这一发现可能有助于估计胎儿年龄。顶骨由位于同一平面或一个在另一个之上的一个或两个初级骨化中心形成（图1、2、3）。在出生后15至19周观察到初级骨化中心的融合（图3）。小梁从初级骨化中心向顶骨周边辐射，并在结节内呈“珊瑚礁”形式（图2和5）。在子宫内生活的第15至19周观察到与初级骨化中心小梁生长不协调的横向骨化（图2）。周边小梁与骨化中心小梁的融合发生在成骨的后期（图4）。29周龄胎儿的顶骨由两层小梁和一个明显的结节组成，矢状缝、冠状缝和前囟除外，在这些部位观察到单层小梁。小梁发育良好且密集排列（图5）。对胎儿顶骨矿物质成分的分析证实，主要元素是钙和磷，且它们的含量随年龄增加（图6和7）。氟含量差异很大，且与年龄无关（图9，表1）。氟在顶骨矿化过程中的重要性需要进一步研究。镁含量随年龄增加（图8），且与钙或磷无相关性。显然，这些元素在矿化过程中发挥不同作用。锌和铁这两种骨的不稳定成分的含量随年龄下降（图10和11）。其中一些变化可能在骨储存过程中发生。
