Literature search
The medical literature was searched electronically and manually for the gross and topographic anatomy of the vaginal introitus, vaginal vestibule, vaginal orifice, and vaginal outlet. In addition, anatomy articles, conference proceedings, and specializing websites were also included. The Medical Subject Headings (MeSH) were applied. The following keywords or phrases were used: the human vagina, vaginal outlet gross human vaginal outlet topographic anatomy, human vaginal introitus gross anatomy, human vaginal topographic anatomy, human vaginal orifice gross anatomy, human vaginal orifice topographic anatomy, perineal body location, vaginal posterior-distal laceration, vaginal outlet (vaginal introitus, and vaginal orifice) histology, posterior vaginal colporrhaphy.
Results Anatomy
The vaginal outlet wall was in the anatomical region of the external genitalia between the membranous urethral sphincter anteriorly, the fossa navicularis posteriorly, and laterally. It was connected to the labia minora. The deep segment (the hymeneal plate) of the vaginal outlet wall fused directly with the vaginal wall and was topographically positioned in the vertical orientation in the direction of a) superiorly towards the vaginal canal; b) inferiorly to the fossa navicularis; c) anteriorly towards the posterior perineal urethra; d) laterally to the surface of the inner labia, Fig. 1B.
Grossly, the vaginal outlet wall was the distal ending of the vaginal wall and showed a different anatomical structure than the vaginal wall. Furthermore, it was the narrowest part of the vagina. The vaginal outlet wall was naturally slightly projecting outward, and it appeared as a “belt-like” structure surrounding all vaginal walls (the anterior, posterior, and lateral), Fig. 1B. The crease separated the vaginal outlet wall a) anteriorly by the inferior membranous urethral sphincter; b) posteriorly by the fossa navicularis; c) laterally by the labia minora. The vaginal outlet wall was a monolithic structure composed of three layers, Fig. 1, Fig. 2. The vaginal outlet ring layer demonstrated much less elasticity to palpations than the vaginal walls and the hymeneal plate. After dissecting the soft tissue of the hymen, the hymeneal ring looked like smooth, white tissue and macroscopically resembled cartilage. Superiorly, this elastic cartilage was fused with the soft tissues of the hymeneal membrane and inferiorly with the hymal plate. Such a subdivision of the vaginal outlet wall into the layers was somewhat arbitrary but valuable for comprehension. The hymeneal ring rested on the hymeneal plate, and both structures created a protuberance. The hymeneal plate was a mixture of soft to palpation, elastic, muscular, connective tissues, and reddish, and had more stretchable tissues than the hymeneal ring, Fig. 1B.