目的　探讨妊娠早期胎儿鼻后三角区的正常超声解剖，对比二维超声图像和三维容积数据重建的图像。  方法　对89名进行胎儿颈后透明层（NT）筛查的健康孕妇，留取胎儿鼻后三角区的正中矢状切面、冠状切面和横切面的二维超声图像，留取断层超声显像（TUI）技术重建的各切面超声图像，对比分析各解剖结构。  结果    （1）二维超声和TUI均可获得各切面，正中矢状切面可显示胎儿鼻骨和腭，冠状切面可显示双侧上颌骨额突和原发腭组成的鼻后三角，横切面可显示鼻后三角和腭的解剖关系；（2）二维超声和TUI比较，鼻后三角区正中矢状切面和冠状切面图像的合格率和质量无明显差别(P>0.05)，但是TUI重建的横切面质量要优于二维超声(P<0.05)。  结论　二维和TUI均可良好显示妊娠早期胎儿的鼻后三角区解剖，为腭裂的早期诊断提供参考依据。

Objective　To investigate and compare two-dimentional and multiplanar sonograms of fetal retronasal triangles during the first trimester of pregnancy.　Methods　Sonographic data from 89 healthy pregnant women at the time of first-trimester period were collected. The mid-sagittal, coronal, transverse and multiplanar views of fetal retronasal triangle were evaluated and analyzed.　Results　Both 2D and TUI views showed the retronasal triangle clearly. The fetal nasal bone and palate showed clearly on the mid-sagittal views, retronasal triangle composed with processus frontalis maxillae and palate showed on coronal views, the relationship of retronasal triangle and palate showed clearly on the transverse views. The qualified rate and scores in the mid-sagittal and coronal views showed no difference between 2D and TUI views (P>0.05), but  was more better on TUI than 2D, for transverse views (P<0.05).　Conclusions　Both 2D and TUI could determine the retronasal triangle during the first trimester of pregnancy. The sonographic examination of retronasal triangle may be useful in the early diagnosis of cleft palate.