Orientation of the Uterine Fundus in Reference to the Longitudinal Axis of the Body

Abstract

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. 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. 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. 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.