There are three levels of vaginal support as described by DeLancey (Fig. 5.23) (40). Level I support consists of paracolpium that suspends the apical portion of the vagina and is comprised of the cardinal-uterosacral ligament complex. Level II support comprises the paracolpium that is attached to the vagina laterally via the arcus tendineus fasciae pelvis and superior fascia of the levator ani. Level III support consists of the distal vaginal attachments: anteriorly, via fusion of the urethra to the vagina, laterally, to the levators, and posteriorly, with the perineal body.
Figure 5.23 DeLancey levels of support. (Modified from DeLancey JOL. Anatomic aspects of vaginal eversion after hysterectomy. Am J Obstet Gynecol 1992;166:17–28, with permission.)
Disruption of level I support may lead to prolapse of the uterus or vaginal vault, while damage to level II and III supports predispose to anterior and posterior vaginal prolapse. All levels of defective support should be repaired during reconstructive surgery.
Blood Supply The blood supply to the vulva is as follows: 1.
External pudendal artery (from femoral artery), internal pudendal artery 2.
The blood supply to the superficial and deep perineal compartments is as follows: 1.
Internal pudendal artery, dorsal artery of the clitoris 2.
Venous drainage—internal pudendal veins, which are richly anastomotic 3.
Innervation The innervation to the vulva is from branches of the following nerves: 1.
2.
3.
Lateral femoral cutaneous nerve of the thigh (perineal branch) 4.
Perineal nerve (branch of pudendal) 5.
Superficial and deep perineal compartments, innervated by the perineal nerve
Perineal Body The perineal body or central perineal tendon is critical to the posterior support of the lower aspect of the anterior vaginal wall. It is a triangle-shaped structure separating the distal portion of the anal and vaginal canals that is formed by the convergence of the tendinous attachments of the bulbocavernosus, the external anal sphincter, and the superficial transverse perinei muscle. Its superior border represents the point of insertion of the rectovaginal (Denonvilliers) fascia, which extends to the underside of the peritoneum covering the cul-de-sac of Douglas, separating the anorectal from the urogenital compartment (41). The perineal body plays an important anchoring role in the musculofascial support of the pelvic ﬂoor. It represents the central connection between the two layers of support of the pelvic ﬂoor—the pelvic and urogenital diaphragm. It also provides a posterior connection to the anococcygeal raphe. Thus, it is central to the definition of the bilevel support of the ﬂoor of the pelvis.
Anal Triangle The anal triangle includes the lower end of the anal canal. The external anal sphincter surrounds the anal triangle, and the ischiorectal fossa is on each side. Posteriorly, the anococcygeal body lies between the anus and the tip of the coccyx and consists of thick fibromuscular tissue (of levator ani and external anal sphincter origin) giving support to the lower part of the rectum and the anal canal.