Nakao T
Department of Orthopaedic Surgery, Saga Social Insurance Hospital, Japan.
Fukuoka Igaku Zasshi. 1998 Feb;89(2):56-63.
A number of studies on sexual differences in the ilium have been reported. However, most of these studies have focused on the adult ilium. With regard to sexual differences in the fetal ilium, few studies have been carried out. Especially, there have few studies regarding sexual differences in the fetal ilium using dry bones. In the present study, sexual differences in the morphological characteristics of the greater sciatic notch were investigated using dry fetal iliac bones. We examined 212 fetuses (106 males and 106 females) measuring 20.0 cm or more in fetal length with free of gross malformations or deformities which were collected at Saga Medical School. The iliac bones were excised from these fetuses and dried as materials for study. Fetal length was measured in the fully extended position and was classified into six groups each for males and females in 5-cm increments, giving a total of twelve groups. The inner lateral surface of the greater sciatic notch was magnified 25x using projector, traced, and the tracings were inputted to a computer (7600/120: Apple Co. Ltd) using a flatbed scanner. The width and height of the greater sciatic notch were measured, as well as the area of the greater sciatic notch. No sexual differences were noted regarding the increase in the width of the greater sciatic notch in fetuses up to 39.9 cm in fetal length. In fetuses measuring between 40.0 anf 44.9 cm, a significant sexual difference was observed, with the increase in greater sciatic notch width markedly greater in females. With respect to the increase in the height of the greater sciatic notch, no significant differences were noted. No significant differences were observed in the total area of the greater sciatic notch in fetuses up to 39.9 cm in fetal length. On the other hand, a significant sexual difference was observed in fetuses measuring 40.0 cm or more, with the total area markedly increased in females. In addition, no significant differences were found in the area between the two sides of the greater sciatic notch in fetuses up to 39.9 cm in fetal length, although significant differences were observed in fetuses measuring 40.0 cm or more. In female fetuses 40.0 cm or more in fetal length, the greater sciatic notch was found to be wider than in males, and the peak of the greater sciatic notch was displaced in the anteroinferior direction, farther from the auricular surface of the ilium and nearer the pubic bone. Thus these female fetuses show morphological characteristics of the adult female pelvic bone. Based on the results obtained, it is concluded that sexual differences can be identified in fetuses from the 8th month of pregnancy (fetal length 40.0 cm or more).
已有多项关于髂骨性别差异的研究报道。然而，这些研究大多聚焦于成人髂骨。关于胎儿髂骨的性别差异，相关研究较少。特别是，使用干燥骨骼研究胎儿髂骨性别差异的研究更是寥寥无几。在本研究中，我们使用干燥的胎儿髂骨对坐骨大切迹的形态特征性别差异进行了研究。我们检查了212例胎儿（106例男性和106例女性），这些胎儿采自佐贺医科大学，胎儿身长20.0厘米及以上，无明显畸形或发育异常。从这些胎儿身上切除髂骨并干燥，作为研究材料。胎儿身长在完全伸展位测量，并按5厘米增量将男性和女性各分为六组，共十二组。使用投影仪将坐骨大切迹的内侧表面放大25倍，进行描绘，然后使用平板扫描仪将描绘图输入计算机（7600/120：苹果公司）。测量了坐骨大切迹的宽度、高度以及面积。在胎儿身长39.9厘米及以下时，坐骨大切迹宽度增加方面未发现性别差异。在身长40.0至44.9厘米的胎儿中，观察到显著的性别差异，女性坐骨大切迹宽度增加明显更大。关于坐骨大切迹高度的增加，未发现显著差异。在胎儿身长39.9厘米及以下时，坐骨大切迹总面积未观察到显著差异。另一方面，在身长40.0厘米及以上的胎儿中观察到显著的性别差异，女性的总面积明显增加。此外，在胎儿身长39.9厘米及以下时，坐骨大切迹两侧的面积未发现显著差异，而在身长40.0厘米及以上的胎儿中观察到显著差异。在胎儿身长40.0厘米及以上的女性胎儿中，发现坐骨大切迹比男性更宽，且坐骨大切迹的峰值向前下方向移位，离髂骨耳状面更远，离耻骨更近。因此，这些女性胎儿表现出成年女性骨盆骨的形态特征。根据所得结果，得出结论：在妊娠8个月（胎儿身长40.0厘米及以上）的胎儿中可以识别出性别差异。
