Orientation of the uterine fundus in reference to the longitudinal axis of the body: a 3-dimensional sonographic study.

OBJECTIVES: The aim of this pilot study was to measure the angle of rotation of the uterus at the fundus from horizontal using 3-dimensional sonography in women presenting for annual gynecologic examinations. METHODS: A total of 51 patients participated in the study. All patients underwent transvaginal sonography, and 3-dimensional volumes were acquired. The cervicouterine angle and the angle of rotation at the fundus were measured. RESULTS: The uteri were noted to be anteverted in 64.7%, retroverted in 25.5%, and euverted in 9.8%. They were noted to be pointing toward the right side of the pelvis in 49.0%, to the left side in 39.2%, and at the midline in 11.8%. The median cervicouterine angle was 122° (interquartile range [IQR], 105°-137°). The median angle of rotation at the fundus away from horizontal in either a clockwise or counterclockwise direction on the transverse B-plane was 10.4° (IQR, 7.1°-19.0°), with a maximal angle of 43°, and on the coronal C-plane, it was 10.0° (IQR, 3.0°-20.0°), with a maximal angle of 43°. Noneuverted uteri were more likely to be rotated at the fundus. CONCLUSIONS: Our study reveals that, contrary to traditional thinking, the uterus can be rotated at the fundus in relation to the body (z-axis) along the longitudinal axis of the cervical canal.