Lecture 16: Pelvic Walls, Muscles & Fascia Flashcards
Where does piriformis exit the pelvis?
Greater sciatic foramen on posterior wall
Where is obturator interns located?
Lateral pelvic wall, moves out via lesser sciatic foramen
What is the pathway of the pelvic fascia?
Lines surface of obturator interns and follows it down to bony attachment, thickens in the middle to form tendinous arch
What is found in the tendinous arch?
Attachment for levator ani
What is the function of levator ani?
Separated pelvis and perineum, pressure maintenance, continence, support pelvic viscera, increase intra-abdominal pressure
What is present between levator ani and obturator internus?
Pudendal/olcax canal - passage for NVB supplying pelvic floor
What viscera lies over the obturator nerve?
Ovary
What is formed in the middle of the pelvic floor and what is its function?
Raphe - site for muscle attachment
What structures pierce levator ani?
Vagina, urethra, rectum
What are the 3 muscles that made up levator ani?
Pubococccygeus, iliococcygeus, coccygeus
What are the features of puborectalis?
- Inferior to pubococcygeus
- Maintains fecal continence
- Under reflex control as a child and as nervous system develops we take voluntary control
- At rest these fibres kink rectum towards pubis
- Merges with deep part of external anal sphincter
Where does coccygeus attach?
Ischial spine, muscle on pelvic side and sacrotuberous ligament on perineal side
When is the pelvic floor under high pressure?
Post partum
What is the midline fibrous nodule in the perineum and what is its function?
Perineal body - muscle fibres merge here to stabilise the pelvic floor
What is the nerve supply for the pelvic floor?
Segmental supply via S3-4 from above and pudendal nerve below S2-3
Why is the nerve supply above the pelvic floor less dense than below?
Reduced susceptibility to entrapment, irritation
What is the pathway of the pudendal nerve?
Moves into gluteal region through greater sciatic foramen with gluteal artery and then quickly exits pelvis through lesser sciatic foramen – well protected unless there is trauma to the perineal region
What is the key landmark of the pudendal nerve?
Ischial spine
What happens to the uterus/bladder if there is weakness of the pelvic floor?
Prolapse of uterus through vagina or herniation of bladder into urethra
What is cystocoele/urethrocoele?
Hernitation of bladder and urethra into anterior vaginal wall
What is rectocele?
Herniation of rectum into posterior vaginal wall
