Three-dimensional imaging of the human vagina demonstrates that the cross section can be a "W," rather than an "H," and that intravaginal gel can ascend into the endocervix and presumably into the endometrium. © 2004 by American Society for Reproductive Medicine.
Barnhart, K. T., Pretorius, E. S., & Malamud, D. (2004). Lesson learned and dispelled myths: Three-dimensional imaging of the human vagina. Fertility and Sterility, 81(5), 1383–1384. https://doi.org/10.1016/j.fertnstert.2004.01.016