Anatomic relationship between the vaginal apex and the bony architecture of the pelvis: A magnetic resonance imaging evaluation

Objective: This study was undertaken to define anatomic relationships between the vaginal apex and the ischial spines and sacrum for nulliparous women with normal support. Study design: We retrospectively evaluated the magnetic resonance images of 11 consecutive women who underwent pelvic imaging at Johns Hopkins. Coordinates were recorded for the posterior fornix, sacrum, ischial spines, and cervical vaginal junctions. We calculated vector distances with means, SDs, and 95% CIs. Intraclass correlation coefficients tested interobserver reliability and the Wilcoxon signed rank test compared right- and left-sided measurements. Results: Mean age was 30.4 ± 9.1 years. The cervical vaginal junction was 1.6 ± 0.5 cm superior, 1.1 ± 0.5 cm anterior, and 4.7 ± 0.4 cm medial to the ipsilateral ischial spine. The posterior fornix was 1.0 ± 1.0 cm anterior and 5.3 ± 0.8 cm inferior to the second sacral vertebra. There was excellent interobserver reliability (interclass correlation coefficients = 0.997, P < .001) and no detectable difference between sides. Conclusion: Consistent relationships exist betweem the vaginal apex and ischial spines and sacrum, which may be useful in reconstructive pelvic surgery.