anatomy of the pelvic floor Flashcards
what muscles make up the superficial layer of the pelvic floor
anteriorly we have; ischiocavernosus, bulbospongiosus, superficial traverse muscles
posteriorly we have the external anal sphincter
where is the ischiocavernosus located?
it ranges from the ischial tuberosity and ischiopubic ramus all the way to the crus of the clitoris on either side
what is the main function of the ischiocavernosus muscle?
maintains erection of the clitoris
what nerve provides innervation to all of the anterior muscles of the perineum?
the perineal branch of pudendal nerve (S2-S4)
Where is bulbospongiosus muscle located?
can be found directly on either side of the labia and ranges from the central tensdon of the perineum to the inferior fascia of the uro-genital diaphragm
what is the function of bulbospongiosus muscle
it allows to decrease the vaginal opening and contributes to the erection of the clitoris
where is the superficial transverse muscle of the perineum found?
found b/w the vaginal and anal opening; it ranges from the ischial tuberosity to the central tendon of the perineum
where is the external anal sphincter located?
it ranges from the ano-coccygeal raffee to the central tendon of the perineum
what muscles/types of muscles make up the external anal sphincter?
round muscles made up of circular fibers
what is the role of the ano-coccygeal rafee for the EAS?
it immobilizes the sphincter front and back
what is the role of the EAS?
It maintains the anal canal closed
what nerves provide innervation to the EAS?
sacral nerve root 4 and inferior rectal branch of the pudendal nerve (S2-S4)
What muscles make up the urgo-genital diaphragm
external urinary sphincter and the deep transverse muscles
where is the external urinary sphincter located
its found in the urogential diaphragm and ranges from the inferior pubic ramus all the way to the vaginal wall
what is the function of the EUS?
helps to maintain continence and expulses the last few drops of urine in males
what provides innervation to the EUS?
perineal branch of the pudendal nerve
how is the innervation of the EUS?
Its both somatic and autonomic since its made up of both smooth and striated muscles
where is the deep transverse muscles of the pelvic floor located?
located in the urogenital diaphragm and ranges from the ischiopubic ramus near the ischial tuberosity and attaches to the central tendon of the perineum
what is the function of the deep transverse muscles of the pelvic floor?
expulses the last few drops of urine and helps to support the neck of the bladder
what provides innervation to the deep transverse muscles of the pelvic floor
perineal branch of the pudendal nerve
what muscles make up the pelvic diaphragm
the pelvic diaphragm is the deepest layer of the PFM and it is made up of pubovaginalis muscles, puborectalis muscle, pubococcygeus muscle, iliococcygeus muscle
what muscles make up the levator ani
pubovaginalis, puborectalis, pubococcygeus
where is pubovaginalis located
in the pelvic diaphragm; it ranges from the most medial portion of the posterior surface of the pelvic bone and attaches to the urethra and central canal of the perineum
what is the role of the pubovaginalis muscle
supports, elevates the PFM
supports changes of intraabdominal pressure
decreases the diameter of the vaginal hiatus
what nerves innervates all of the muscles that make up the pelvic diaphragm
sacral nerve root 3 and 4 and perineal branch of the pudendal nerve
where it the puboractalis muscle found
it ranges from the posterior surface of the pubis and lateral to the pubovaginalis muscle and attaches to the lateral portion of the anal canal and rectum junction to insert onto the ano-coccygeal raffee
what is the role of the puborectalis muscle
supports and slightly elevates the pelvic floor. allows support to intraabdominal pressure changes
approximates anus to pubis and closes anus
what happens when the ano-rectal angle is greater than 90 degrees
generally associtated with constipation
what determines the ano-rectal angle
the tone of the puborectalis muscle; high tone generally leads to constipation
where is the pubococcygeus muscle located
posterior surface of the pubis and attaches to the posterior surface of the anorectal junction and anococcygeal raffee ranging from the anus to coccyx
its found lateral to puborectalis muscle
what is the role of the pubococcygeus muscle
supports and slightly elevated the pelvic floor
resists changes of intraabdominal pressure
approximates anus to pubis and closes anus
will function to pull everything anteriorly
where is the iliococcygeus muscle found
ranges from the ischial spine and tendinous arch of levator ani to the distal portion of the coccyx and anococcygeal raffee
what is the role of iliococcygeus muscle
supports and elevates the pelvic floor
resists intra-abdominal pressure
approximates anus to pubis and elevates anus
where does the pudendal nerve pass
b/w piriformis and coccygeus muscle and will cross over the lateral part of the sacrospinous ligament to then re-enter via the lesser foramen
what is the alcox canal
canal made of fascia found in the obterator internus muscle where the pudendal nerve exits
how does the pudendal nerve branch out after the alcox canal
inferior rectal nerve
perineal branch
dorsal nerve of the clitoris
