Defects of this support structure may include tears or attenuation of the vaginal fibromuscular wall, or detachment from the pelvic sidewalls, the cervix or cardinal ligament complex, or from the pubis. Specific sites of fibromuscular tears are frequently difficult to recognize.
Physical examination may reveal the following findings: 1.
The presence of a central ballooning-type defect 2.
Descent of the area of the vaginal wall below the bladder neck 3.
Descent of the cervix or apical vaginal area 4.
The presence or absence of sulci extending lateroanteriorly, which would indicate that lateral detachment to the arcus is maintained or lost.
Posterior Compartment The support of the rectum and posterior vagina includes the pelvic ﬂoor musculature and connective tissue posteriorly and Denonvillier’s (pararectal) fascia, which is the fibromuscular layer of the posterior vaginal wall and its lateral attachments to the lateral pelvic ﬂoor (levator) musculature and its fascia (Fig. 27.8). This lateral attachment site, the fascia levator ani, fuses with the arcus tendineus fascia pelvis at the middle to upper level of the vagina
Figure 27.8 Sagittal oblique view of the distal midvagina illustrating lateral connection of the posterior musculoconnective tissue wall to the fascia levator ani and anterior wall to the arcus tendineus pelvis. The attachment sites fuse together at a point closer to the ischial spine where the vagina assumes a more oval shape. (Modified by J. Taylor from illustration by Lianne Krueger Sullivan. From Cundiff GW, Fenner D. Evaluation and treatment of women with rectocele: focus on associated defecatory and sexual dysfunction. Obstet Gynecol 2004;104:1403– 1421, erratum in Obstet Gynecol 2005;105:222, with permission.) and continues to the level of the ischial spine. Less dense, areolar, connective tissue surrounds the rectum and vagina and may supply some support to these structures as well.
The fibromuscular layer at the upper vagina fuses with the paracervical fascia and the fan-shaped cardinal ligament structure. The integrity of the attachment of this posterior vaginal layer to the anterior rectal wall just below the rectal sigmoid junction prevents enterocele formation. In the distal vagina, the fibromuscular layer fuses laterally with the fascia of the puborectalis and then the bulbocavernous muscle and centrally with the perineal connective tissue. Thus, normal posterior support includes a plate of connective tissue that is attached laterally as noted, posteriorly toward sacral segments 2 to 4, and inferiorly to the perineum. This fibromuscular plane not only holds the rectum in place posteriorly, but also aids in preventing perineal descent by suspending the perineum to the sacrum. The constant resting tone of the pelvic ﬂoor muscles, particularly the puborectalis, serve to close the genital hiatus, pulling the distal vagina and anorectal junction toward the pubic symphysis and creating an anorectal angle and a posterior deﬂection of the rectum, vagina, and bladder base.
It has been hypothesized, based on careful cadaveric dissections, that most rectoceles were due to discrete tears in the Denonvillier’s fascia at its lateral, apical, and perineal attachments and centrally within the fascia itself (14). Perineal detachment, along with a defect in the perineal membrane, has been described as a perineal rectocele, which is most commonly associated with reports of difficulty with defecation. Apical attachment defects are generally associated with enteroceles and occasionally sigmoidoceles.