目的　利用三维超声及MRI观测未育女性静息状态及屏气最大用力时盆底断层解剖结构变化并探讨其临床意义。  方法　30例未育健康妇女进行盆腔三维超声及MRI扫描，观测盆腔器官的位置、运动和盆底肌形态并对其进行测量。  结果　不同断层影像上可获得盆底各结构清晰显像，肛提肌厚度为（8.2±1.8）mm，肛提肌裂孔面积为（11.82±2.25）cm2,静息时及屏气用力时盆底形态变化不明显, 盆腔用力时膀胱颈、子宫颈及肛直肠连接较静息状态下均有不同程度的下降，其中膀胱颈(6.1±2.0) mm, 子宫颈(8.9±4.2)mm, 肛直肠连接(14.9±6.1) mm。  结论　断层显像可清晰显示盆底静息及动态解剖结构，为诊断盆底功能障碍性疾病的提供重要依据。

Objective　To evaluate tomographic imaging in pelvic floor anatomy of nulliparous woman both at rest and during pelvic strain and discuss the clinical significance.　Methods　Thirty asymptomatic nulliparous volunteers were enrolled for 3D  sonography and dynamic MRI； all tomographic imagings were used to observe position and movement of pelvic organs and the shape of pelvic floors, and to measure the thickness of muscle 1ayers and the dimensions of the levator hiatus．Results　A normal pelvic floor could be demonstrated by tomographic image in the axial , coronary  and sagittal planes. Measurements of levator ani and the hiatal area was (8.2±1.8) mm and (11.82±2.25) cm2 at rest, respectively．Compared with the rest state, the bladder neck, cervix and the anorectus were lower during maximaI pelvic strain (the difference is 6.1±2.0、8.9±4.2and 14.9±6.1mm, respectively ).   Conclusions    Tomographic imaging can show the morphological characters of the pelvic floor both at rest and during pelvic strain and may be useful in the diagnosis of female pelvic floor disorders.