Figure 10.

Cervical development. (A–D) are sagittal sections of the female reproductive tract of a 16 week fetus (A=H&E, B=ISL1 immunostain, C-D=keratin 19 immunostain). Boundaries between the vagina, cervix and uterus are nebulous up to 18 weeks, when vaginal fornices become apparent (F). (B) ISL1 immunostaining is strong in vaginal stroma, absent in uterine stroma, with a sharp fall off in staining intensity at the mid-point of the uterovaginal canal (red arrow in B). Keratin 19 immunostaining (C–D) may also be indicative of vaginal-exocervical boundary. Cervical glands are prominent at 21 weeks of gestation (E). Epi. = Epithelium, Mes. = mesenchyme, Strat. Sqm. = Stratified squamous, Vag. Plate = vaginal plate, Endo-Cx = endocervix. From Robboy et al (2017) with permission.