The position of the vagina and uterus depends on various fascial supports and ligaments derived from specific thickening of areas of the fascial support (Figs 21.1–21.4). There has been a paradigm shift in our understanding of the anatomy of pelvic floor supports and with it the pathophysiology of development of pelvic organ prolapse. There are three levels of pelvic organ support that are clinically relevant and conceptually easier to grasp. The uterosacral ligaments responsible for providing level I support to the upper vagina and the cervix (and by extension to the uterus) have a broad attachment over the second, third and fourth sacral vertebrae arising posteriorly from the junction of the cervix and the upper vagina running on each side lateral to the rectum towards the sacral attachments. The other important structure is the arcus tendineus fasciae pelvis (ATFP; see Figs 21.3 and 21.5) also known as the ‘white line’ – a condensation of pelvic cellular tissue on the pelvic aspect of the obturator internus muscle. The ATFP runs from the ischial spines to the pubic tubercle and its terminal medial end is known as the iliopectineal ligament (Cooper’s ligament), well known to general surgeons that operate on inguinal and femoral hernias. Extending medially from the white lines are condensed sheets of pelvic cellular tissue suspending the anterior and posterior vaginal walls and the organs underlying these, namely the urinary bladder and the rectum providing level II support. The anterior support to the bladder was previously referred to as the pubovesicocervical fascia or ‘bladder pillars’, whereas the posterior support to the rectum was termed the rectovaginal fascia.

Fig. 21.1 The pelvic diaphragm viewed from below.

Fig. 21.2 Muscles of the pelvic floor, lateral view.

Fig. 21.3 The lateral attachments of the pubocervical fascia (PCF) and the rectovaginal fascia (RVF) to the pelvic sidewall. Also shown are the arcus tendineus fascia pelvis (ATFP), arcus tendineus fasciae rectovaginalis (ATFRV) and ischial spine (IS).

Fig. 21.4 Three-dimensional view of the endopelvic fascia. Notice the location of the cervix in the proximal anterior vaginal segment.

Fig. 21.5 The endopelvic fascia of a post-hysterectomy patient divided into DeLancey’s biomechanical levels: level I, proximal suspension; level II, lateral attachment; level III, distal fusion. (Modified with permission from DeLancey JO (1992) Anatomic aspects of vaginal eversion after hysterectomy. Am J Obstet Gynecol 166:1717. © Elsevier.)

Level III support is provided by the perineal body posteriorly and the pubourethral ligaments anteriorly. The perineal body is a complex fibromuscular mass in to which several structures insert. It is bordered cephalad by the rectovaginal septum (Dennonviller’s fascia), caudad by the perineal skin, anteriorly by the wall of the anorectum, and laterally by the ischial rami. The three-dimensional form has been likened to the cone of the red pine (Pinus resinosa) and it forms the keystone of the pelvic floor a 4 cm × 4 cm fibromuscular structure providing support not just to the lower third of the vaginal wall (part of the genital hiatus) anteriorly but also to the external anal sphincter posteriorly. Attaching laterally to the perineal body are the superficial and deep perineal muscles.

The anterior vaginal wall is supported by the pubovesicocervical fascia, which extends from the ATFP on one side to the ATFP of the other providing a hammock-like level II support. The posterior vaginal wall is supported by the fibrous tissue of the rectovaginal septum that is well defined only in the midline; laterally the hammock-like supports arise from the ATFP.

The uterus is supported indirectly by the supports of the vaginal walls but directly by the uterosacral ligaments. The round and broad ligaments provide weak if any support to the vagina and uterus. Indirect support of the lower third of the vagina and uterus is provided by the intact levator ani (pelvic floor). The role of the latter has always been in doubt, but the puborectalis portion of the levator ani plays a significant role in the distension of the genital hiatus in labour and delivery making it very prone to injury. Injury to this muscle has been postulated to be the cause for vaginal prolapse later in life.

Definitions

Vaginal prolapse

Prolapse of the anterior vaginal wall may affect the urethra (urethrocele), and the bladder (cystocele, Fig. 21.6). On examination, the urethra and bladder can be seen to descend and bulge into the anterior vaginal wall and, in severe cases, will be visible at or beyond the introitus of the vagina. An urethrocele is the result of damage to level III (anterior) support, i.e. the pubourethral ligaments. Cystoceles usually result due to a loss of level II support and usually due to a midline defect in pubovesicocervical fascia. A rectocele is formed by a combination of factors: a herniation of the rectum through a defect in the rectovaginal fascia as well as a lateral detachment of the level II support from the ATFP. This can usually be seen as a visible bulge of the rectum through the posterior vaginal wall. It is often associated with a deficiency and laxity of the perineum. This is the classical level III defect (posterior) affecting the perineal body.

An enterocele is formed by a prolapse of the small bowel through the rectouterine pouch, i.e. the pouch of Douglas, through the upper part of the vaginal vault (Fig. 21.6). The condition may occur in isolation, but usually occurs in association with uterine prolapse. An enterocele may also occur following hysterectomy when there is inadequate support of the vaginal vault. This represents damage to level I support.

Uterine prolapse

Descent of the uterus, which occurs when level I support is deficient, may occur in isolation from vaginal wall prolapse but more commonly occurs in conjunction with it. First-degree prolapse of the uterus often occurs in association with retroversion of the uterus and descent of the cervix within the vagina. If the cervix descends to the vaginal introitus, the prolapse is defined as second degree. The term procidentia is applied to where the cervix and the body of the uterus and the vagina walls protrude through the introitus. The word actually means ‘prolapse’ or ‘falling’ but is generally reserved for the description of total or third-degree prolapse (Fig. 21.7).

Fig. 21.7 Procidentia: a third-degree prolapse of the uterus and vaginal walls.

Symptoms and signs

Symptoms generally depend on the severity and site of the prolapse (Table 21.1).

Table 21.1

Levels of supports, with diagnosis and co-relation with symptoms

Level of pelvic organ support	Organ affected	Type of prolapse	Symptoms
Level I – uterosacral ligaments	Uterus/vaginal vault (post-hysterectomy)	Uterocervical/vault prolapse/enterocele	Vaginal pressure, sacral backache, ‘something coming down’, dyspareunia, vaginal discharge
Level II – arcus tendineus fascia pelvis (ATFP)	Urinary bladder	Cystocele	‘Something coming down’, double voiding, occult stress incontinence, recurrent urinary tract infection
Level II – arcus tendineus fascia pelvis (ATFP)	Rectum	Rectocele	‘Something coming down’, difficult defecation, manual digitation
Level III – anterior (pubourethral ligaments)	Urethra	Urethrocele	‘Something coming down’, stress incontinence
Level III – posterior (perineal body)	Lower third of the vagina/vaginal introitus/anal canal	Enlarged genital hiatus	Vaginal looseness, sexual dysfunction, vaginal flatus, needing to apply pressure to the perineum to evacuate faeces

Mild degrees of prolapse are common in parous women and may be asymptomatic.

There are some symptoms that are common to all forms of prolapse; these include:

• A sense of fullness in the vagina associated with dragging discomfort.

• Visible protrusion of the cervix and vaginal walls.

• Sacral backache is usually relieved on lying down.

Symptoms are often multiple and related to the nature of prolapse. It is important to note that the symptoms (and signs) of prolapse are worse at the end of the day. It is, therefore, of some value, to schedule examination of patients that have typical symptoms of prolapse without its obvious signs a little later in the day.

Staging/grading of prolapse

Baden–Walker halfway system (Fig. 21.8 and Table 21.2)

This system was developed in an effort to introduce more objectivity into the quantification of pelvic organ prolapse. For example, measurements in centimetres are used instead of subjective grades. Nine specific measurements are recorded as indicated in Figure 21.9.

Table 21.2

Primary and secondary symptoms at each site used in the Baden–Walker halfway system

Anatomic site	Primary symptoms	Secondary symptoms
Urethral	Urinary incontinence	Falling out
Vesical	Voiding difficulties	Falling out
Uterine	Falling out, heaviness, etc.
Cul-de-sac	Pelvic pressure (standing)	Falling out
Rectal	True bowel pocket	Falling out
Perineal	Anal incontinence	Too loose (gas/faeces)