Pelvic Floor

PELVIC FLOOR

Dr.Shailaja Shetty, Professor & HOD, Dept. of Anatomy, MSRMC, Bangalore OUTLINE

 INTRODUCTION  UROGENITAL DIAPHRAGM  PELVIC DIAPHRAGM  PERINEAL BODY  PELVIC PERITONEUM INTRODUCTION  The outlet of the true pelvis is called the pelvic floor.

 It is gutter shaped.

 Inclined at an angle of 5-15 degrees from the horizontal. UROGENITAL DIAPHRAGM  It is a musculo-fascial partition across the pubic arch, between the ischial tuberosities and the pubic symphysis.  Lies superficial to the pelvic diaphragm  In female the U-G diaphragm is less defined due to the presence of vagina. Hence it is also called triangular ligament UROGENITAL DIAPHRAGM Consist of:  2 muscles: Sphincter urethrae and Transversus perinei profundus  2 fasciae: Superior and inferior fasciae of urogenital diaphragm  2 structures piercing it: vagina behind and urethra in front UROGENITAL DIAPHRAGM MUSCLES FORMING U-G DIAPHRAGM 1. SPHINCTER URETHRAE: 2. TRANSVERSE PERINEI  It encircles the membranous PROFUNDUS: urethra  Situated behind the sphincter  It has a superficial part and urethrae deep part. SPHINCTER URETHRAE Superficial part:  Arise from the transverse perineal ligament and adjacent pubic arch  Passes backwards by the side of the urethra  Inserted into the perineal body Deep part:  Arise from the inner side of the ischio-pubic ramus and pudendal canal.  It encircles the urethra and is continuous with similar fibers of opposite side TRANSVERSE PERINEI PROFUNDUS  Arises from the inner surface of the ischial ramus .  Inserted into the perineal body where it intermingles with the opposite side muscles. NERVE SUPPLY: Both muscles are supplied by muscular branches of the perineal nerve. RELATIONS Below: Contents of the superficial perineal pouch Above:  Neck of the urinary bladder in female  Anterior fibres of the levator ani muscles  Anterior recesses of the ischiorectal fossae In front:  Triangular gap between arcuate pubic ligament and transverse perineal ligament .  Transmits the dorsal vein and nerve of clitoris

Behind:  Ischio-rectal fossa and its contents. ACTIONS OF U-G DIAPHRAGM

1. Supports the bladder. 2. Constricts the vagina. 3. Fixes the perineal body. 4. Sphincter urethrae exerts voluntary control of micturition. Expels last drops of urine after bladder stops contraction. PELVIC DIAPHRAGM

 Separates the pelvis from the perineum.  It is slung like a hammock around the midline pelvic effluents-the urethra, vagina and the anal canal. Consist of:  2 muscles: levator ani and coccygeus.  2 fasciae: superior and inferior fasciae of pelvic diaphragm. PELVIC DIAPHRAGM PELVIC DIAPHRAGM LEVATOR ANI  Consists of iliococcygeus and pubococcygeus.  Both arises in continuity from the : 1. Pelvic surface of the body of the pubis. 2. Tendinous arch or the white line of the pelvic fascia. 3. Pelvic surface of the ischial spine.  ILIOCOCCYGEUS: Gets inserted into the lower 2 pieces of the coccyx and ano-coccygeal raphe

 PUBOCOCCYGEUS: 1. PUBOCOCCYGEUS PROPER: Gets inserted into ano-coccygeal raphe and the tip of coccyx 2. PUBORECTALIS: the fibres wind around the posterior aspect of the ano-rectal junction and are continuous with the fibres of opposite side – puborectal sling  PUBOANALIS: Inserted into the walls of the anal canal, between the external and internal anal sphincters  PUBOVESICALIS/ PUBOVAGINALIS: Pass around the vagina and gets inserted into the perineal body. COCCYGEUS  This muscle is also called ischiococcygeus.  Triangular in shape.  Situated behind the levator ani.  The muscle arises from the apex of the ischial spine and the sacrospinous ligament.  Inserted into the first 2 pieces of coccyx and last piece of sacrum NERVE SUPPLY:

LEVATOR ANI:  posterior part is supplied by S2 from the pelvic surface.  Anterior part is supplies by S3 & S4 from the perineal surface. COCCYGEUS:  Supplied by S4 and S5 sacral nerves PECULIARITIES OF PELVIC DIAPHRAGM 1. Gutter shaped and slopes towards the anterior part of pelvic outlet 2. Anterior fibres of levator ani overlap with the posterior fibres and forms the ano-coccygeal raphe. 3. Most fibres of iliococcyeus and ischiococcygeus disintegrate hence the major brunt of support of pelvic viscera falls on the pubococcygeus. OPENINGS OF THE PELVIC DIAPHRAGM  HIATUS UROGENITALIS:  HIATUS RECTALIS:  HIATUS OF SCHWALBE: Abnormal opening when the levator ani fails to arise from the obturator fascia. The pelvic viscera may herniate into the corresponding ischiorectal fossae. HIATUS OF SCHWALBE WITH INTESTINAL HERNIATION FUNCTION OF PELVIC DIAPHRAGM

1. Counteracts the downward thrust of the pelvic viscera during raised intra-abdominal pressure.

2. The anterior fibres act as sphincter vaginae 3. Coccygeus pulls the coccyx forwards after it displaced backwards during defecation and parturition 4. During defecation the puborectal sling relaxes and the anal and rectal canal forms a straight tube. At the same time the puboanalis elevates the anus. 5. In parturition, the fetal head rests on the puborectal sling , this helps in the forward rotation of the head into the lower part of the birth canal.

6. In micturition, the pubo-coccygei relax and the bladder neck descends, this stimulates the contraction of the detrusor and helps in voiding the urine. PERINEAL BODY  It is a pyramidal fibromuscular node intervening between the urogenital and the anal diaphragm.  The perineal body is tethered into the central perineal skin, and is often puckered over it.  In females it lies directly posterior and is attached to the posterior commissure of the labia majora and the introitus of the vagina. PERINEAL BODY  It receives the perineal muscles in three strata; 1. Deep stratum: levator ani 2. Intermediate stratum: muscles of deep perineal pouch and deep part of external sphincter 3. Superficial stratum: bulbospongiosus, transverse perinei superficialis, superficial part of external sphincter APPLIED ANATOMY  Perineal body maybe torn in females during parturition.  If not properly repaired, the hiatus urogenitalis becomes wider when the levator ani muscles contract.  Through this gap the pelvic viscera maybe displaced downwards producing prolapse of uterus. Peritoneum Peritoneal cavity

Abdomen Pelvic proper cavity

Supracolic Infracolic

Right Left Suprahepatic Subhepatic part part Supracolic compartment

Intraperitoneal Extraperitoneal

Left Left Right Right anterior posterior anterior posterior

Left Left Right Right Suprahepatic subhepatic suprahepatic subhepatic Supracolic compartment

Intraperitoneal Extraperitoneal

Right Left Extraperitoneal Extraperitoneal space space Infracolic compartment

Right part Left part

b/w b/w Asc.colon & desc.colon & mesentry mesentry Paracolic gutters

Right paracolic gutter Left paracolic gutter Pelvis-Peritoneum

Rectovesical pouch Rectouterine pouch(pouch of Douglas)  Between rectum and posterior wall of uterus  Scottish anatomist, James Douglas  Dependent pouch in pelvis of females Rectouterine pouch(pouch of Douglas) Pouch of Douglas Clinical importance:  Dependent pouch- e.g: Infection, abscess, peritonitis, Ruptured ovarian cyst, pelvic abscess, endometriosis, haemoperitoneum: preferentially fluid collects here.  The rectouterine pouch is often reached through the posterior fornix of the vagina- called as culdocentesis  Peritoneal dialysis in end stage renal failure. Vesicouterine pouch  Between anterior wall of uterus & superior surface of the urinary bladder Pararectal fossa Paravesical fossa  The peritoneum of the anterior pelvic wall covers the superior surface of the bladder and on either side of this viscus forms a depression, termed the paravesical fossa

Space of Retzius  The retropubic space (also known as the prevesical space or cave of Retzius)  It is an extraperitoneal space located posterior to the pubic symphysis and anterior to the urinary bladder.

Space of Retzius  Floor- endopelvic fascia, perivesical fascia & levator ani fibres  Function: support for bladder & proximal urethra(cushion).  Contents : Vesical venous plexus and fat. Presacral space  The presacral space is a space in the pelvis, behind the rectum and in front of the coccyx and sacrum.  It is lined by presacral fascia  Widening of the presacral space is one of the diagnostic indicators of the diseases involving pelvic pathology and rectal involvement Presacral space Boundaries: 1. Superiorly - peritoneal reflections 2. Laterally - ureter, iliac vessels 3. Inferiorly - levator ani and coccygeus muscles Presacral space

 Contents of Presacral space:  Fat  Mesenchymal tissue  Lymph nodes  Nerve plexuses  Blood vessels