Okumura Misaki, Ishikawa Aoi, Aoyama Tomoki, Yamada Shigehito, Uwabe Chigako, Imai Hirohiko, Matsuda Tetsuya, Yoneyama Akio, Takeda Tohoru, Takakuwa Tetsuya
Human Health Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Congenital Anomaly Research Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
PLoS One. 2017 Apr 6;12(4):e0173852. doi: 10.1371/journal.pone.0173852. eCollection 2017.
The pelvic skeleton is formed via endochondral ossification. However, it is not known how the normal cartilage is formed before ossification occurs. Furthermore, the overall timeline of cartilage formation and the morphology of the cartilage in the pelvis are unclear. In this study, cartilage formation in the pelvic skeletons of 25 human fetuses (crown-rump length [CRL] = 11.9-75.0 mm) was observed using phase-contrast computed tomography and 7T magnetic resonance imaging. The chondrification center of the ilium, ischium, and pubis first appeared simultaneously at Carnegie stage (CS) 18, was located around the acetabulum, and grew radially in the later stage. The iliac crest formed at CS20 while the iliac body's central part remained chondrified. The iliac body formed a discoid at CS22. The growth rate was greater in the ilium than in the sacrum-coccyx, pubis, and ischium. Connection and articulation formed in a limited period, while the sacroiliac joint formed at CS21. The articulation of the pubic symphysis, connection of the articular column in the sacrum, and Y-shape connection of the three parts of the hip bones to the acetabulum were observed at CS23; the connection of the ischium and pubic ramus was observed at the early-fetal stage. Furthermore, the degree of connection at the center of the sacrum varied among samples. Most of the pelvimetry data showed a high correlation with CRL. The transverse and antero-posterior lengths of the pelvic inlet of the lesser pelvis varied among samples (R2 = 0.11). The subpubic angle also varied (65-90°) and was not correlated with CRL (R2 = 0.22). Moreover, cartilaginous structure formation appeared to influence bone structure. This study provides valuable information regarding the morphogenesis of the pelvic structure.
骨盆骨骼通过软骨内成骨形成。然而，在骨化发生之前正常软骨是如何形成的尚不清楚。此外，软骨形成的总体时间线以及骨盆中软骨的形态也不清楚。在本研究中，使用相衬计算机断层扫描和7T磁共振成像观察了25例人类胎儿（顶臀长[CRL]=11.9-75.0mm）骨盆骨骼中的软骨形成。髂骨、坐骨和耻骨的软骨化中心首先在卡内基阶段（CS）18同时出现，位于髋臼周围，并在后期呈放射状生长。髂嵴在CS20形成，而髂骨体的中央部分仍为软骨状态。髂骨体在CS22形成盘状。髂骨的生长速度大于骶尾骨、耻骨和坐骨。连接和关节在有限的时期内形成，而骶髂关节在CS21形成。在CS23观察到耻骨联合的关节、骶骨关节柱的连接以及髋骨三部分与髋臼的Y形连接；在胎儿早期观察到坐骨和耻骨支的连接。此外，骶骨中心的连接程度在不同样本中有所不同。大多数骨盆测量数据与CRL高度相关。小骨盆骨盆入口的横径和前后径在不同样本中有所不同（R2=0.11）。耻骨下角也有所不同（65-90°），且与CRL无关（R2=0.22）。此外，软骨结构的形成似乎会影响骨骼结构。本研究为骨盆结构的形态发生提供了有价值的信息。
