The cervix is a narrow structure connecting the vagina and the uterus, often described as the neck of the uterus. This anatomical gateway is designed as a protective, restrictive barrier. Understanding the cervix’s anatomy clarifies what kinds of objects and materials might pose a problem in this area.
Understanding the Cervical Barrier
The cervix is a cylinder-shaped tissue, approximately three to five centimeters long, that projects into the top of the vagina. It contains the endocervical canal, a central passage connecting the uterine cavity to the vagina. This canal has two openings: the internal os, which opens into the uterus, and the external os, which opens into the vagina.
The external os is typically very small, often described as a pinhole in people who have not given birth. The structure is muscular and fibrous, making it rigid compared to the rest of the uterus. This rigidity maintains its barrier function, preventing the passage of substantial objects into the uterus.
During menstruation, the external os opens slightly to allow blood to pass, and it softens and changes position around ovulation to facilitate sperm entry. Because of its small size, large foreign objects cannot physically enter the cervical canal. However, objects can become lodged high in the vaginal vault, resting firmly against the external opening of the cervix. This position creates the sensation of something being trapped or difficult to retrieve.
Foreign Objects That Can Become Lodged
Instances of an object becoming “stuck” usually involve items placed in the upper vagina, resting near the cervix. A forgotten tampon or a menstrual cup positioned too high can become wedged against the cervix, making removal difficult. The object is trapped in the narrow space surrounding the cervix, not penetrating the canal itself.
Contraceptive barriers, such as diaphragms or cervical caps, are intentionally placed to cover the cervix. They create a suction seal that can make them challenging to dislodge. Similarly, a vaginal pessary used to support pelvic organs, if improperly sized or shifted, can become lodged and cause discomfort against the cervix.
Intrauterine devices (IUDs) are an exception, as the device is placed inside the uterus. The strings attached to the IUD extend through the cervix into the top of the vagina for checking and removal. If these strings retract into the cervical canal or curl up, retrieval becomes inaccessible. This requires a healthcare provider’s intervention to locate the strings or remove the device.
Natural Materials That Pass Through or Rest Near the Cervix
The cervix manages the passage of natural biological materials, which can sometimes feel like an obstruction. During pregnancy, the cervix forms the cervical mucus plug, a thick collection of mucus that acts as an infection barrier. The expulsion of this plug, often near the end of pregnancy, is a sudden discharge of material that was temporarily resting in the canal.
Menstrual processes require the cervix to manage the movement of tissue and blood clots. Large blood clots, common during heavy flow, must pass through the external os. The temporary presence of a large clot can cause pelvic cramping as the cervix contracts to expel the material.
Following a miscarriage or abortion, the body expels products of conception, including tissue and blood. Retained tissue in the uterine cavity or cervical canal can cause prolonged bleeding and pain. The presence of retained material necessitates medical evaluation to ensure the passage is clear.
Recognizing Signs of a Problem and Medical Intervention
When material is retained, it creates an environment where bacteria multiply, leading to infection. The most common symptom is a foul-smelling vaginal discharge, which may appear yellowish, greenish, or gray. This is often accompanied by pelvic pain, pressure, or discomfort.
Fever, chills, or flu-like symptoms indicate a progressing infection and require immediate medical attention. Other signs include unusual vaginal bleeding outside of the normal menstrual cycle or difficulty with urination. Delaying care risks complications like pelvic inflammatory disease or, in rare cases with retained tampons, toxic shock syndrome.
A healthcare provider performs a pelvic examination, often using a speculum to visualize the upper vagina and the cervix. If a foreign object is present, specialized tools, such as long forceps, are used for safe retrieval. For retained biological material, an ultrasound confirms the presence of tissue. A procedure like a dilation and curettage may be necessary to ensure the uterus is empty and the cervical canal is unobstructed.