Pelvic Walls Flashcards
What are the subdivisions of the pelvis?
Two lateral walls, a posterior wall, and a floor
The bony framework of the lateral wall is what part of the hip bone?
That which lies below the pelvic brim
What two things primarily cover the lateral wall of the pelvis?
Obturator internus muscle and obturator fascia
What makes up the bony framework of the posterior wall of the pelvis?
Sacrum and coccyx
Is the posterior wall convex or concave anteriorly?
Concave
What covers the lateral portion of the posterior wall of the pelvis?
Piriformis muscle and coccygeus (ischiococcygeus) muscle
Why is the floor of the pelvis more important among humans than other mammals?
Because we walk upright
What two things make up the pelvic floor?
Peritoneum (above) and pelvic diaphragm (below)
What is the space located between the rectum and bladder called?
Rectovesical pouch
What is the lowest point in the peritoneum of the male?
Rectovesical pouch
What is the space located between the rectum and uterus?
Rectouterine pouch
What is the space located between the bladder and uterus?
Vesicouterine pouch
What is a less common but possible site for ectopic pregnancy of the pelvic wall area?
Rectouterine pouch
Ascites and blood can pool in which downward reflections of the peritoneum?
Rectovesical or rectouterine pouch
What is the major support structure for pelvic viscera?
Pelvic diaphragm
The pelvic diaphragm consists of which muscles?
Coccygeus (ischiogoccygeus) and levator ani muscles
What is the major constituent of the pelvic diaphragm?
Levator ani muscle
What is the opening of the pelvic diaphragm that transmits the urethra in males and both the urethra and vagina in females?
Urogenital hiatus
What is the opening of the pelvic diaphragm that is found in both sexes?
Anal aperture
What is the origin of the coccygeus muscle?
Ischial spine and sacrospinous ligament
What is the insertion of the coccygeus muscle?
Coccyx and lower part of sacrum
What is the nerve supply of the coccygeus muscle?
Anterior primary rami of 3rd and 4th sacral nerves
What is the function of the coccygeus muscle?
Supports pelvic viscera, draws coccyx forward
What is the origin of the levator ani muscle?
Body of pubis, tendinous arch, ischial spine
What is the insertion of the levator ani muscle?
Coccyx and anococcygeal ligament
What is the nerve supply of the levator ani muscle?
Anterior primary rami of 3rd and 4th sacral nerves, perineal branch of pudendal nerve
What is the function of the levator ani muscle?
As a whole, supports pelvic viscera. Specialized parts of the levator ani perform other functions
What is the shape of the levator ani muscle?
Funnel-shaped
What are the three parts of the levator ani muscle?
Iliococcygeus, pubococcygeus, and puborectalis
What is the most posterior part of levator ani?
Iliococcygeus
What is the main part of levator ani?
Pubococcygeus
What part of the levator ani is located around the urogenital hiatus?
Pubococcygeus
What part of the pubococcygeus forms a sling around the urethra beneath the prostate in the male?
Puboprostaticus
What part of the pubococcygeus forms a sling around the urethra and vagina in the female?
Pubovaginalis
What part of the pubococcygeus attaches to the anorectal junction?
Puboanalis
Which parts of the pubococcygeus function in micturition?
Puboprostaticus and pubovaginalis
What is micturition?
“Bladder emptying”
What is the most important muscle for maintaining fecal matter (other than the anal sphincter)?
Puborectalis
Where is puborectalis located?
Behind the anorectal junction as a sling
What is the function of puborectalis?
Maintains angle at the anorectal junction (perineal flexure)
When is puborectalis relaxed?
During defecation
What is an extra function of puborectalis?
Directs the fetal head forward during parturition
What is the tendinous arch of levator ani?
Curved thickening of the obturator fascia which gives origin to parts of the pubococcygeus and iliococcygeus
What can misaligment of the sacrum affect when it comes to the pelvis?
Urinary continence, bowel/fecal continence, parturition, and integrity of the pelvic floor