**4. Important connective tissue structures at the pelvic floor (figures 2 and 8)**

At the pelvic floor at least 9 sites of connective tissue can be defined as loose. With regard to its function, P. Petros (2010) divides the connective tissue defects in three zones (figure 2).

The **anterior zone**, which reaches from the external meatus of the urethra to the bladder neck, embraces three important structures:

The extraurethral ligament runs from the pubis anteriorly to the meatus urethrae anterior to the perineal membrane.

The pubourethral ligament, a ligament with key relevance for stress urinary continence, originates from the lower end of the posterior surface of the pubic symphysis and descends

1. The anterior and medial portions of the pubococcygeus muscle (PCM) arise on either side from the inner surface of the pubic bone and attach to the lateral walls of the distal vagina (Zacharin 1963, Petros und Ulmsten 1997, Corton 2009). This muscle portion, called pubococcygeus muscle (PCM) by Petros and Ulmsten (1993) and pubovaginal muscle by Corton (2009) can pull the distal vagina forward to close the distal urethra during effort (coughing or straining). This muscle needs intact pubourethral ligaments

2. The levator plate in the upper layer runs horizontally, goes into the posterior wall of the rectum, and thus plays a major role in any backward movement of this organ. This muscle needs intact pubourethral and uterosacral ligaments and an intact perineal body

3. The conjoint longitudinal muscle of the anus (LMA) is a striated muscle which constitutes the middle layer. It is vertically oriented, creates the downward force for bladder neck closure during effort and stretches open the outflow tract during micturition. It takes fibers superiorly from the levator plate (LP), the lateral part of the pubococcygeus and puborectalis muscle. It is well anchored by extra-anal sphincter (Courtney 1950). This muscle needs intact uterosacral ligaments for optimal action. 4. The puborectalis muscle (PRM) originates just medially to PCM and traverses all three muscle layers. It is orientated vertically and runs forward medially below PCM. It is closely applied to the lateral walls of the rectum and surrounds them (Courtney 1950). The lower layer of pelvic floor muscles is an important anchoring layer. It consists of perineal membranes and component muscles - bulbocavernosus, ischiocavernosus and the deep and superficial transverse perinei muscles. The deep transverse perinei muscle anchors the upper part of the perineal body to the descending pubic ramus. It is a strong muscle and it stabilizes the perineal body laterally. The external anal sphincter acts as a tensor of the perineal body and represents the principal insertion point of the LMA. The bulbocavernosus muscle stretches and anchors the distal part of the urethra. The ischiocavernosus muscle helps stabilize the perineal membrane and may act to stretch the external urethral meatus laterally via its effect of the bulbocavernosus. Between the extra-anal sphincter and the coccyx lies the postanal plate, a tendinous structure which also contains striated muscles

The striated rhabdosphincter of the urethra surrounds the urethra in the middle third of its

**4. Important connective tissue structures at the pelvic floor (figures 2 and 8)**  At the pelvic floor at least 9 sites of connective tissue can be defined as loose. With regard to its function, P. Petros (2010) divides the connective tissue defects in three zones (figure 2).

The **anterior zone**, which reaches from the external meatus of the urethra to the bladder

The extraurethral ligament runs from the pubis anteriorly to the meatus urethrae anterior to

The pubourethral ligament, a ligament with key relevance for stress urinary continence, originates from the lower end of the posterior surface of the pubic symphysis and descends

for optimal action.

to optimize its various actions.

inserting into the extra-anal sphincter (Petros 2010).

length for approximatly 1,5 cm (Oelrich 1983).

neck, embraces three important structures:

the perineal membrane.

like a fan to insert into the pubococcygeus muscle and lateral part of the mid urethra (Zacharin 1963, Petros 1998).

The suburethral vagina acts as a hammock for the urethra. The antero-medial portion of the pubococcygeus muscles is attached laterally on each side of the hammock

In the **middle zone**, which reaches from the bladder neck to the cervix, three further structures are important:

PCM: pubococcygeus muscle, LP: levator plate, LMA: longitudinal muscle of the anus PRM: puborectalis muscle, EAS: extraanal sphincter PUL: pubourethral ligament, ATFP: Arcus tendineus fasciae pelvis, CL: cardinal ligament CX-Ring: cervical ring, USL: uterosacral ligament, RVF: rectovaginal fascia PB: perineal body, B: bladder, Ut: uterus, R: rectum N: stretch receptor at bladder base

Fig. 2. Important muscles and connective tissue structure at the pelvic floor (from P. Petros 2010, by permission)

The arcus tendineus fascia pelvis (ATFP) are horizontal ligaments which arise just superior to the pubourethral ligaments at the pubis symphysis and insert into the ischial spine. The vagina is suspended from the ATFP by its fascia, much like a sheet slung across two

The Role of Altered Connective Tissue in the Causation of Pelvic Floor Symptoms 9

abdominal forces stretch loose tissues in the anterior zone (pubourethral ligament, extraurethral ligament, hammock), leading to overlengthening of the rhabdosphincter. According to Gordon`s relation between muscle length and muscle force, as soon as the muscle force diminishes … (by half/etc), the patient is stress incontinent. Overstretched connective tissue leads also to an increased radius within the rhabdosphincter and the urethra. According to Laplace's law, the pressure within the urethra correlates inversely to the radius within the rhabdosphincter. In loose connective tissue, the pressure within the urethra thus diminishes in line with the increasing radius. The Hagen-Poiseuille`s law is also helpful in describing continence. The resistance to flow within the urethra in stress situations correlates directly to the length of the urethra and indirectly to the radius within the urethra in the 4th power (Bush et al. 1997). Stress in patients with loose connective tissue will open the urethra. The stress flow then correlates to the radius of the

In other words, loose connective tissue can lead to reduced muscle force by overstretching the muscle, reduced urethral pressure by increasing the radius within the rhabdosphincter,

These correlations have a major impact on interpretation of urodynamic results and should

Petros has been developing the midurethral sling since 1986 based on research on the laxities of the vagina and supporting ligaments and loose connective tissue. (Petros and

a) b) c) B=bladder; U=urethra; V=vagina; CX=cervix; R=rectum; PUL=pubourethral ligament; Bv=attachment

Fig. 3. Directional movements of bladder and urethra during effort. a) Lateral xray in resting position, sitting. b) Lateral xray during straining, same patient, shows forward movement of distal vagina and urethra and backward/downward rotation of proximal vagina and urethra ,around the pubourethral ligament (PUL) at the midurethral point. c) Muscle actions during effort- schematic view. PCM pulls the distal vagina forwards to close the distal urethra; LP/LMA stretch the proximal vagina and urethra backwards/downwards to close

of bladder base to vagina; LMA= conjoint longitudinal muscle of the anus; LP=levator plate;

off the proximal urethra. (From PPetros 2010, by permission).

and reduced resistance to flow by widening the urethral radius.

urethra in 4th power.

be considered in the future.

Ulmsten 1990, 1993)

USL=uterosacral ligament.

washing lines (Nichols 1989). The cardinal ligaments are attached to the cervical ring and pubocervical fascia and extend laterally towards and above the ischial spine. The cervical ring surrounds the cervix and acts as an attachment point for the cardinal and uterosacral ligaments as well as the pubocervical and rectovaginal fascia. It consists mainly of collagen. The "pubocervical fascia" – a term still used by surgeons - stretches from the lateral sulci of the vagina to the anterior part of the cervical ring, it is a vaginal muscularis and fibromuscular wall (Corton 2009).

In the **posterior zone**, which reaches from the cervix to the anal canal, the following 3 structures can be loose.

The uterosacral ligaments arise from the sacral vertebrate S2,3,4 and attach to the cervical ring posteriorly. It is an effective insertion point of the downward muscle force, the longitudinal muscle of the anus (LMA). The rectovaginal fascia extends as a sheet between the lateral rectal pillars, from the perineal body below to the levator plate above. It is attached to the uterosacral ligaments (USL) and the fascia surrounding the cervix. The perineal body lies between the distal third of the posterior vaginal wall and the anus below the pelvic floor. It is 3-4 cm long. According to DeLancey (1999), it is formed primarily by the midline connection between the halves of the perineal membrane. It is the insertion point of bulbocavernosus muscle and deep and superficial transverse perinei muscles.

**Micturition** Broken line below bladder signifies relaxation of PCM; LP/LMA vectors actively open out the urethra exponentially decreasing frictional resistance to micturition

**Defecation** Broken line behind rectum signifies relaxation of PRM; LP/LMA vectors actively open out the anorectum, exponentially decreasing frictional resistance to defecation
