**3. Pelvic floor muscles and their functions (figure 2)**

In many studies morphology of pelvic floor muscles has been explained with only few limited reference to muscle action. There is no doubt that the pelvic floor muscles and ligaments have immense importance for stress incontinence, micturition and anorectal functions. It was P. Petros who explained the directional muscle forces (Petros and Ulmsten 1993, Petros and Ulmsten 1997) and their significant role in pelvic floor dysfunctions.

From a functional and clinical aspect, it is important to consider 4 major muscle groups of the pelvic floor which are able to move the vaginal wall and pelvic floor organs (Petros 2010):

The Role of Altered Connective Tissue in the Causation of Pelvic Floor Symptoms 7

like a fan to insert into the pubococcygeus muscle and lateral part of the mid urethra

The suburethral vagina acts as a hammock for the urethra. The antero-medial portion of the

In the **middle zone**, which reaches from the bladder neck to the cervix, three further

pubococcygeus muscles is attached laterally on each side of the hammock

PCM: pubococcygeus muscle, LP: levator plate, LMA: longitudinal muscle of the anus

CX-Ring: cervical ring, USL: uterosacral ligament, RVF: rectovaginal fascia

PUL: pubourethral ligament, ATFP: Arcus tendineus fasciae pelvis, CL: cardinal ligament

Fig. 2. Important muscles and connective tissue structure at the pelvic floor (from P. Petros

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

PRM: puborectalis muscle, EAS: extraanal sphincter

PB: perineal body, B: bladder, Ut: uterus, R: rectum

N: stretch receptor at bladder base

2010, by permission)

(Zacharin 1963, Petros 1998).

structures are important:


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

The striated rhabdosphincter of the urethra surrounds the urethra in the middle third of its length for approximatly 1,5 cm (Oelrich 1983).
