Week 5.1 - The Pelvic floor Flashcards
How does the pelvic floor contribute to continence?
-Exerts a sphincter action on rectum and vagina
What is the pelvic floor composed of?
- Pelvic diaphragm -> levator ani, coccygeus and fascial coverings
- Superficial muscles -> anterior and posterior perineum
Describe levator ani
-Paired muscles extending from posterior pubis, obturator internus fascia and ischial spines consisiting of puborectalis, pubococcygeus and iliococcygeus
What structures pierce the perineal membrane?
-Urethra/vagina
What is the anterior perineum? What does it contain?
- Anterior triangle of the perineum bounded by the pubic symphysis, ischiopubic rami and an imaginary line between the ischial tuberosities
- Contains the deep perineal pouch, perineal membrane, superficial perineal pouch and deep and superficial perineal fascia
Where in the perineum are the bulbourethral glands?
-Within the urogenital diaphragm
What is the perineal body?
- Fibromuscular junction between anterior and posterior perineum
- Site of attachment for anal sphincter, bulbospongiosus, transverse perineal muscles, levator ani and external urethral sphincter
What is the result of damage to the perineal body in women?
-Vaginal prolapse
What is the posterior perineum? What does it contain?
- Posterior triangle of the perineum bounded by the coccyx, sacrotuberous ligament and imaginary line between the ischial tuberosities
- Contains the anal apeture, external anal sphincter and ischioanal fossa
What is the ischiorectal fossa? What is its clinical significance?
- Fat filled space lateral to anal canal and inferior to pelvic diaphragm which allow expansion of anal canal during defecation
- Infection can track back to the glutes
What is the perineum?
-Diamond shaped area below the pelvic diaphragm which is divided into the anterior and posterior triangles by an imaginary line between the ischial tuberosities
Name the ‘gaps’ which are present in the pelvic floor
- Urogenital hiatus
- Rectal hiatus
What are the functions of the pelvic floor?
- Support the pelvic viscera
- Resistance to increasing intra-abdominal pressures such as coughing
- Urinary and fecal continance
What innervates levator ani?
-Pudendal nerve (S2-S4)
Describe puborectalis
What is its main function
- U shaped muscle extending from posterior pubis, past urogenital hiatus, around the anal canal
- Maintain position of rectoanal junction and fecal continence (relaxes during defecation
Describe pubococcygeus
- Main constituent of levator ani
- Arise from posterior pubis and obturator internus fascia to coccyx and anococcygeal body
- Also surround the vagina or prostate
Describe iliococcygeus
-From the ischial spines and obturator internus fascia to coccyx and anococcygeal body
Describe coccygeus
- Smallest and most posterior muscle of pelvic diaphragm
- From ischial spines to lateral coccyx/sacrum along sacrospinous ligament
What innervates coccygeus?
-S4/S5
Primary damage to the pelvic diaphragm leads to what problems?
-Urinary and fecal incontinence
What is an episiotomy?
- Mediolateral cut to the perineum to widen the vestibule during childbirth
- Mediolateral cut is more painful in short term but better in ling term -> midline cut risks fecal incontinence
State the boundaries of the perineum
- Anterior = pubic symphysis
- Posterior = tip of coccyx
- Lateral = ischial tuberosities
- Roof = pelvic diaphragm
- Floor = skin and fascia
What is the purpose of the perineal membrane?
- Site of attachment for superficial external genitalia muscles
- Support the pelvic viscera
What is the deep perineal pouch?
-Potential space between the pelvic diaphragm superiorly and perineal membrane inferiorly
(contains the urogenital diaphragm)
What is the superficial perineal pouch? What does it contain?
- Located in the anterior perineum
- Potential space between the perineal membrane superiorly and perineal fascia inferiorly
- Contains erectile tissue of penis/clitoris, ischiocavenosis, bulbospongiosus and superficial transverse perineum, and bartholin glands
Where is the deep perineal fascia?
-Fascia covering the superficial perineal muscles in the anterior perineum
Describe the innervation of the perineum
-Pudendal nerve
-S2,3 and 4 keeps your guts off the floor
Describe the levels of endopelvic fascia in women
- Level 1 -> uterosacral ligament supports uterus from above
- Level 2 -> Sheets of fascia at either side of the vagina keep the vagina attached to the side walls
- Level 3 -> Perineal membrane and Perineal body
Describe how a weak pelvic floor leads to urinary incontinence
- Normally pressure is exerted on internal urethral sphincter by the pelvic floor muscles in such a way that an increase in intraabdominal pressure is matched by an increase in sphincter pressure = continence
- When the pelvic floor is weak, increase in intraabdominal pressure is not matched by the sphincter and the bladder neck falls through the hiatus -> pressure is not matched by the sphincter = incontinence
Describe the effects of childbirth on the pelvic floor
- Stretches/damage to pelvic floor and perineal muscles -> muscle weakness
- Stretches pudendal nerve -> neuropraxia and muscle weakness
- Stretch/rupture of supporting ligaments
What is the urogenital diaphragm?
- Located in the deep perineal pouch
- Consists of the deep transverse perineum and sphincter urethrae (external urethral sphincter) between two layers of fascia
- The inferior layer of fascia is the perineal membrane
