The Squamocolumnar Junction (SCJ) is located at the point where the columnar epithelium and the squamous epithelium meet. Its location varies throughout life as a result of
metaplastic changes in the columnar epithelium of the cervix. Before puberty the SCJ is usually located at the external os; in the parous women it may be on the ectocervix; after the menopause the SCJ is usually within the endocervical canal.