Cervix

The portion of the cervix that projects into the vagina (vaginal part or ectocervix), like the vagina is covered with stratified squamous epithelium. This epithelium is changed abruptly to simple columnar epithelium of the cervical canal in the transformation zone.

• The transformation zone for women in reproductive age is just outside the external os, while in prepubertal and menopausal women it is in the cervical canal.

Metaplastic changes in the transformation zone constitute precancerous lesions of the cervix.