The term endocervical refers to the inner part of the cervix, the lower, narrow end of the uterus that connects to the vagina. The endocervix forms the endocervical canal, a small channel that serves as a passageway between the uterus and vagina. This canal is about 4 centimeters long.
The Endocervix and Its Function
The endocervix is lined with a mucous membrane containing glandular cells. The primary role of these cells is to produce cervical mucus, a fluid that changes in consistency throughout the menstrual cycle in response to hormonal fluctuations.
Around the time of ovulation, the mucus becomes thin and watery, which helps facilitate the movement of sperm into the uterus for potential fertilization. At other times in the cycle and during pregnancy, the mucus becomes thick, creating a protective plug. This barrier helps prevent bacteria and other pathogens from entering the uterus.
Role in Medical Screenings
Routine medical screenings like the Pap smear and HPV test involve collecting cells from the cervix. A complete sample includes cells from both the outer cervix (ectocervix) and the inner endocervical canal. The presence of endocervical cells on a test result indicates a comprehensive sample was collected from this inner area.
The area where the outer squamous cells and the inner glandular cells meet is called the transformation zone. This region is where most abnormal cellular changes linked to HPV infection tend to develop. Healthcare providers use a small brush or swab to sample cells from the endocervical canal to ensure any changes in this area are detected early.
An adequate sample from the transformation zone allows for a more accurate analysis of cervical health. While a test lacking endocervical cells is not automatically inadequate, their presence confirms a thorough collection was performed. This is particularly relevant when monitoring previous abnormal results.
Common Endocervical Conditions
Several conditions can affect the endocervix, many of which are benign. Endocervical polyps are common, benign growths that develop within the cervical canal, often resulting from chronic inflammation (endocervicitis). While most are asymptomatic, they can sometimes cause irregular bleeding or discharge.
Inflammation of the endocervix, known as endocervicitis, can be caused by infections or other irritants. Pap smear results may show “reactive cellular changes,” which describe how cells respond to irritation and do not indicate malignancy. These findings can be associated with infections or the presence of an intrauterine device (IUD).
Test results may show atypical glandular cells (AGC), which are found in less than 0.5% of Pap tests and require further investigation. This can be a sign of a more significant precancerous condition called adenocarcinoma in situ (AIS). AIS is a precursor to endocervical adenocarcinoma and is often associated with high-risk HPV types. A finding of AIS requires an excisional procedure to remove the abnormal tissue.