An introitus is an opening to a hollow tube or a hollow organ. In anatomy, the introitus is the name for the opening of the vaginal orifice, or vaginal canal, in females. The word is derived from two compound Latin words meaning "to go" and "into." Introitus is also a medical term for describing the various degrees of cervical or uterine prolapse into the vaginal canal.
The vagina is a hollow, tube-shaped organ, with the uterus and cervix at the top, nestled deep in the abdominal cavity, with the vulva, the external genitalia protruding out from the introitus. A system of muscles and ligaments surrounding the vaginal wall and the interior reproductive organs uphold the vagina, the uterus and other internal organs, such as the bladder and rectum. For some women, the vaginal muscles are unable to hold the weight of the internal reproductive organs, and they droop or collapse, called a "prolapse."
Cervical prolapse is more common in older women past their childbearing years, but can occur in younger women from trauma or as a result from surgical procedures. In prolapse, the muscles of the vaginal canal become slackened or damaged, unable to hold up the uterus at the topmost end of the vaginal canal. The cervix, which constitutes the base of the uterus, drops into the vagina canal in varying degrees of prolapse.
Medical practitioners have classified the various degrees of cervical and uterine prolapse into three degrees. A first degree prolapse is the condition when the bottom of the uterus — the cervix — has dropped into the vaginal canal. Second degree prolapse occurs when the cervix has dropped to the area of the introitus. A third degree prolapse occurs when the cervix protrudes out of the vagina through the introitus. Uterine procidentia, also called pelvic organ prolapse is a very serious medical emergency in which the uterus drops completely out of the vaginal canal, distending out from the introitus.
Surgical correction of prolapse and procidentia includes the insertion of pessaries, which are small rings fitted into the vaginal or abdominal cavity. These rings provide uterine and vaginal support and relieve symptoms such as incontinence. Uterine prolapse and procidentia can be prevented by strengthening the muscles of the vagina and introitus. Kegel exercises, a technique of contracting and relaxing the pelvic floor muscles, have been shown to strengthen the muscle tone surrounding the genitalia.