PELVİC FLOOR

The pelvic floor muscles form the “floor” of the pelvis and perform four important functions:

   Supportive: by counteracting passive gravitational pull and dynamic intraabdominal pressures impacting the pelvic viscera in conjunction with the inner core muscles forming the canister theory of core stabilization.
   Sphincteric: by shortening in an anterosuperior direction, these muscles squeeze off the urethra,
vagina, and anorectal junction to maintain urinary and fecal continence.
   Sexual: by rhythmically contracting during orgasm to enhance sexual satisfaction.
   Postural stabilizer: by working with the transverse abdominus, multifidi, and pulmonary diaphragm,
the pelvic floor creates the bottom of the inner core
“canister”.
   Poor pelvic floor strength is associated with pelvic organ prolapse and urinary or fecal incontinence. Ninetyseven percent of women will experience some level of supportive dysfunction in their lifetime, leading to “falling” of the bladder, rectum, uterus, or small intestine.Urinary or fecal incontinence is experienced by as many as 72% of women of all ages. Fecal incontinence is thought to be grossly underreported because of the associated social stigma. However, urinary incontinence
is amenable to treatment, with reports of an 84% success rate using the Kegel exercise (controlled voluntary contractions used to strengthen the pelvic floor).
   Sexual dysfunction may be related to weak pelvic floor musculature and urinary incontinence. Thirty-one percent of men and 43% of women between the ages of 18 and 59 years report concerns during physical intimacy, some of which are related to urinary incontinence and a weak pelvic floor. Up to 80% of aging women have similar concerns. The pelvic floor muscles can become weakened from childbirth, poor patterns of muscle recruitment, medical comorbidities such as diabetes, abdominopelvic surgical procedures, constipation, chronic cough, hormonal changes, and loss of muscle mass with aging. Because of the frequency of pelvic floor weakness, pelvic floor muscle strength should be routinely assessed to rule out muscle weakness, spasm, or dyscoordination in the presence of lumbopelvic, urologic, gynecologic, sexual, or gastrointestinal dysfunction.
  
     

The pelvic floor muscles include the following:

   • Presence of pelvic floor muscle activation: clinical observation, external perineal palpation, vaginal or rectal digital palpation, EMG, and pressure gauges.

   • Quantification of pelvic floor muscle strength: manual muscle testing with rectal or vaginal palpation, vaginal cones, and vaginal squeeze pressure.

   • Additional visualization of the pelvic floor musculature may be done with abdominal or pelvic twodimensional ultrasound, ultrasound, and magnetic resonance imaging.

Anatomy of the Pelvic Floor

    Muscles of the pelvic floor are difficult to visualize, particularly because most students do not have the opportunity to dissect this region in anatomy class. In both males and females, there are five muscles of the urogenital region that differ in size and disposition in relation

to the male and female external genitalia. These five muscles are grouped into superficial and deep layers. Superficial muscles include three portions of the levator ani (puborectalis, pubococcygeus, iliococcygeus) and the ischiococcygeus. Connective tissue and the deep transverse perinei comprise the deep layer.

     The superficial layer is the outermost layer; it resembles a sling and is shaped like a figure eight. Although the superficial layer is relatively thin in terms of mass, it is highly sensitive.        This area is responsible for controlling the anal and urethral sphincters, so these muscles play an important role in continence. In order to work effectively the sphincters need the support of the rest of the pelvic floor, particularly the connective tissue elements. Additionally, because the abdominals share the same connective tissue attachments as the pelvic floor musculature, in

many women they too need to be strengthened, along with the pelvic floor musculature.

     The deep layer of the pelvic floor is the real workhorse of the pelvic floor. The deep pelvic floor muscles have the highest resting muscle tone in the body and play a vital role in movement, posture, and breathing. These muscles must continuously support the weight of the pelvic and abdominal organs when the person is upright. The deep pelvic floor is sometimes

called the pelvic diaphragm. Like its companion, “the roof” or the pulmonary diaphragm, it has minimal sensory innervation and its movement is not felt directly.

     When it works well, the pelvic floor functions like a wellbalanced trampoline and has amazing tensile strength and elasticity. It plays a crucial role in ensuring spinal stability and free locomotion. Deep abdominal muscles in front, the multifidi around the spine, and the pulmonary diaphragm all must work together synergistically with the pelvic diaphragm. Thus “there is no core without the floor”.

MUSCLES OF THE PELVIC FLOOR (PERINEUM)

   The levator ani forms the main part of the pelvic diaphragm, the cranial layer of the pelvic floor. It is primarily supplied by direct branches of the sacral plexus (S3-S5). To a small degree the pudendal nerve contributes to its innervation as well. The levator ani is made up of the following three muscles:

• Puborectalis muscle: originates lateral from the symphysis on both sides and encircles the rectum (anorectal junction) which causes a ventral bend between rectum and anal canal. Partly it is interwoven with the external anal sphincter.
• Pubococcygeus muscle: runs from the pubic bone (lateral of the origin of the puborectalis muscle) to the tendinous center of the perineum, anococcygeal body and tailbone. In men, medial muscle fibers are partly connected to the prostate.
• Iliococcygeus muscle: extends more laterally from the fascia of obturator internus muscle to the tailbone. As a whole the levator ani builds a V-shaped structure. Both levator arms limit a triangle opening (levator hiatus) which is divided by prerectal fibers into the urogenital hiatus (ventral) and anal hiatus (dorsal). The urogenital hiatus is the pathway for the urethra and, in women, the vagina. The rectum runs through the anal hiatus.