Vaginal Anatomy on MRI: New Information Obtained Using Distention

OBJECTIVES: To demonstrate and confirm the presence of three anatomic zones of the vagina (a superficial sphincteric zone; a central wedge shaped transition zone; and a deep, expanded forniceal zone) using pelvic magnetic resonance imaging with contrast distention of the vagina. METHODS: A total of 107 consecutive female pelvic magnetic resonance imaging scans using vaginal contrast distention were retrospectively reviewed. The images were observed for the three-zone configuration. Anteroposterior and transverse diameter measurements were taken in the proximal, mid, and distal sphincteric, transition, and forniceal zones. Means and standard deviations were calculated at each site. Adjacent sites were compared using paired t tests. RESULTS: The three-zone configuration was observed in all of the cases but one. Statistically significant increases and decreases of mean anteroposterior diameters occurred at all levels expected by visual observation. CONCLUSIONS: The three-zone configuration of the distended vagina was confirmed by this study. The configuration of the vagina is more complex than has been reported previously. This configuration may facilitate parturition and may be useful in the design of intravaginal devices.