Structure and histology of the cervical TZ.

A. Schematic representation of the cervix showing the TZ between ectocervix and endocervix. B. Histology of the cervical TZ showing the stratified squamous epithelium and underlying Nabothian cysts. C. Schematic showing the surface features of ectocervix, endocervix and TZ that aid in tissue dissection. The ectocervix is easily identified because the surface is smooth, white, and shiny with no mucous. The endocervix surface is rough, red in color, and covered with mucous. The TZ contains Nabothian cysts (swollen glands due to occlusion of ducts by squamous metaplasia). These large cysts are easily visible and diagnostic for the TZ. D. Photograph of a typical cervical specimen showing each region.