Original Article

OPEN: Vaginal Anatomy on MRI: New Information Obtained Using Distention

Authors: Alan H. Appelbaum, MB BCh BAO, Jeffrey K. Zuber, MA, Roberto Levi-D’Ancona, MD, Harris L. Cohen, MD


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.

Full Article

Having trouble viewing the article content below? Click here to open it directly.


Fig. 1. Sagittal T2 fast relaxation fast spin echo section of the pelvis performed with vaginal distension by endoluminal contrast. This image shows a more complex contour of the vagina than has been described previously. The distended vagina demonstrates three zones: a narrow tubular sphincteric zone at the introitus, a wedge-shaped transition zone, and an expanded forniceal zone.

Download Image

Fig. 2. Sagittal T2 fast relaxation fast spin echo section of the pelvis performed with vaginal distension by endoluminal contrast. Measurements of the proximal, mid, and distal sphincteric transition and forniceal zones were taken as illustrated above. S1, introitus; S2, midpoint between S1 and S3; S3, transition between sphincteric and transition zones; T1, 1 cm above S3; T2, origin of the urethra; T3, midpoint between T2 and F1; F1, anterior fornix; F2, cervical os; F3, posterior fornix.

Download Image

Table 1. Patient characteristics (N = 100)

Download Image

Fig. 3. Compressed reconstruction image of the pelvis performed with vaginal distension by endoluminal contrast. This image better demonstrates the overall funnel-like configuration of the vagina and again shows the three-zone configuration. Free intraabdominal fluid and the urinary bladder also are visible.

Download Image

Fig. 4. A, Axial T2 fast relaxation fast spin echo section of the pelvis performed with vaginal distension by endoluminal contrast. In the sphincteric zone the puborectalis muscle forms a sling around the urethra, vagina, and rectum. The lateral walls of the vagina are fused with the puborectalis, the anterior wall is fused with the urethra, and the posterior wall is fused with the perineal body. B, Coronal T2 fast relaxation fast spin echo section of the pelvis performed with vaginal distension by endoluminal contrast. Coronal images demonstrate the paracolpium connecting the lateral walls of the vagina to the pubococcygeus muscles. This determines the contour of the lateral walls of the vagina in the transition zone. Note the large endometrioma visible superior and to the left of the uterus.

Download Image

Table 2. Vaginal diameters (N = 89)

Download Image

Table 3. Comparisons of vagina diameter levels (N = 89)

Download Image


1. Standring S. Gray’ Anatomy: The Anatomical Basis of Clinical Practice. 41st ed. London:Elsevier;2016.
2. Sinnatamby CS. Last’ Anatomy: Regional and Applied. 12th ed. London:Churchill Livingstone;2011.
3. Pendergrass PB, Reeves CA, Belovicz MW, et al. The shape and dimensions of the human vagina as seen in three-dimensional vinyl polysiloxane casts. Gynecol Obstet Invest 1996;42:178-182.
4. Pendergrass PB, Reeves CA, Belovicz MW, et al. Comparison of vaginal shapes in Afro-American, caucasian and hispanic women as seen with vinyl polysiloxane casting. Gynecol Obstet Invest 2000;50:54-59.
5. Morgan KF, Jr. Casts of the vagina as a means of evaluating structural changes and treatment. Calif Med 1961;94:30-32.
6. Jung SA, Pretorius DH, Padda BS, et al. Vaginal high-pressure zone assessed by dynamic 3-dimensional ultrasound images of the pelvic floor. Am J Obstet Gynecol 2007;197:52.e1-7.
7. Barnhart KT, Izquierdo A, Pretorius ES, et al. Baseline dimensions of the human vagina. Hum Reprod 2006;21:1618-1622.
8. Suh DD, Yang CC, Cao Y, et al. Magnetic resonance imaging anatomy of the female genitalia in premenopausal and postmenopausal women. J Urol 2003;170:138-144.
9. Tunn R, DeLancey JO, Quint EE. Visibility of pelvic organ support system structures in magnetic resonance images without an endovaginal coil. Am J Obstet Gynecol 2001;184:1156-1163.
10. Chen L, Ramanah R, Hsu Y, et al. Cardinal and deep uterosacral ligament lines of action: MRI based 3D technique development and preliminary findings in normal women. Int Urogynecol J 2013;24:37-45.
11. Ramanah R, Berger MB, Chen L, et al. See it in 3D!: researchers examined structural links between the cardinal and uterosacral ligaments. Am J Obstet Gynecol 2012;207:437.e1-7.
12. Umek WH, Morgan DM, Ashton-Miller JA, et al. Quantitative analysis of uterosacral ligament origin and insertion points by magnetic resonance imaging. Obstet Gynecol 2004;103:447-451.
13. DeLancey JO. Anatomic aspects of vaginal eversion after hysterectomy. Am J Obstet Gynecol 1992;166:1717-1728.
14. Delancey J. Surgical anatomy of the female pelvis. In: Rock JA, Jones HW, , eds. Te Linde’ Operative Gynecology. 10th ed. Philadelphia:Wolters Kluwer Health;2008;: 82-112.
15. Posner GD, Black A, Jones GD, et al. Oxorn Foote Human Labor and Birth. 6th ed. New York:McGraw-Hill Education;2013.
16. Bamberg C, Rademacher G, Gü F, et al. Human birth observed in real-time open magnetic resonance imaging. Am J Obstet Gynecol 2012;206:505.e1-6.
17. McGowan L. Peritonitis following the vaginal douche and a proposed alternative method for vaginal and vulvar care. Am J Obstet Gynecol 1965;93:506-509.
18. Egenolf GF, McNaughton RH. Chemical peritonitis resulting from vaginal douche report of a case. Obstet Gynecol 1956;7:23-24.