Lecture 18 RH Flashcards
What are the different layersof the pelvic walls?
Bones, Joints, and connecting ligaments
Muscles
Pelvic fascia (parietal layer of peritoneum)(somatic nerves and parietal vessels)
Pelvic viscera
Where does piriformis originate and insert?
Piriformis goes from the middle 3 parts of the sacrum and goes through the greater sciatic foramen and attaches to the lower limb.
Which muscles are involved in the rotation of the hip?
obturator internis
piriformis
Where does the obturator originate and insert?
Starts at the obturator foramen and goes aroung the lesser sciatic foramen between the ischial spine and the iscial tuberosity and also attaches to the lower limb.
What covers the surface of obturator internis?
pelvic fascia covers the surface of obturator internis
Where does the levator ani get its fascia from?
Obturator internis fascia has an extension from the middle which forms the tendinous arch covering the levator ani.
What is the significance of the levator ani’s position?
It separates the pelvic cavity and the perineum
What is the perineum?
perineum is the location through which tubular viscera pass. (rectum, vagina, urethra)
What are the other names of the levator ani muscles?
pelvic floor or pelvic diaphragm
What is found between the levator ani and the obturator internis?
between levator ani and obturator internis is the pudental canal (aka alcox canal)
What are the contents of the pudental canal?
Pudental vein
Pudental artery
Pudental nerve
these vessels innervate and supply the pelvic floor and perineum.
What kinds of nerves can be found in the pelvis? Where are they found?
posterior pelvic wall contains the sacral plexus and nerves from the lumbar plexus pass through the pelvic cavity.
What major artery supplies the pelvis?
internal iliac artery supplies the pelvic cavity
What connects the levator ani and the obturator internis?
a raphe is formed where the levator ani meets the obturator internus.
What is the result if there is disruption in the levator ani muscles?
incontinence of urine and feces.
What are the components of levator ani muscles?
pubococcygeus (puborectalis)
iliococcygeus
(ischio) coccygeus
Under reflex and voluntary control.
What is interesting about the puborectalis?
Inferior to the pubococcygeus is the puborectalis. In a child it is under reflex control but then becomes voluntary during adulthood.
What is the function of the puborectalis?
puborectalis forms a sling around the rectal canal and is important for fecal continence.
What other structures does the levator ani muscles work on?
These muscles act on the anal canal, vagina, and urethra as well and form puboanalis, pubovescialis, and pubourethralis.
levator ani is always under pressure especially after childbirth. In females pelvic outlet is wider.
What is the structure of the ischiococcygeus muscle?
ischio coccygeus on the left side is made up of muscle
On the perineal (right) side it is the sacrotuberous ligament
In animals it is called agitator chordae which moves the tail. In humans it is very variable.
What is the perineal body?
perineal body is found in both males and females in females it is much larger than it is in males.
What is the function of the perineal body?
muscles originate from the perineal body.
How does the arrangement of the viscera in the perineum influence where they rest?
urethra and vagina rest against the pubis due to the tilt of the pelvis as a result of the lumbar lordosis
How does puborectalis assist the rectum in fecal continence?
puborectalis merges with the external anal sphincter. This is important for fecal continence because it produces a kink in the rectum.
How does the pubococcygeus muscle assist in urinary continence?
Prostate has the urethra passing through it (prostatic urethra). Some fibers go to anal canal and bladder and these help maintain continence of the urine.
What is the perineal body? What is its function?
In both males and females is a midline fibrous nodule called the perineal body, it is important for the attachments of the muscles (including puborectalis) of the pelvis and its larger in females than in males.
What are the functions of the pelvic floor?
Support pelvic viscera
raises pelvic floor (increases intrabdominal pressure)
important for continence
Important for defacation
important for childbirth (rotation and flexion of fetal head).
What sacral spinal nerves are responsible for levator ani innervation?
“spinal segments 2, 3, and 4 keep the ass off the floor.”
What is the origin of the segmental nerve supply of levator ani from above?
Segmental supply is from S3 and S4 from above.
Where does the pudendal nerve originate from?
Pudendal nerve from below from S2 and S3
What is the difference in density between the segmental and pudental pelvic floor nerves?
Segmental pelvic floor nerves from above are less dense than the ones from below. Reason for this is that if all nerve supply was from pelvic cavity then they are more susceptible during injury.
How does the pudental nerve travel before it reaches the levator ani muscles?
From pelvic cavity to gluteal region with superior gluteal artery and then back through the lesser sciatic foramen into the perineum. This region is typically anaesthatised during childbirth near the ischial spine (landmark)
How is the uterus arranged relative to the bladder?
the uterus kinks over the bladder wall from above.
What are some problems that can arise if there is weakness in the pelvic floor?
Weakness of pelvic floor may result in prolapse of pelvic viscera through the vagina.
Herniation of the bladder may occur into the urethra or the anterior vaginal wall (cystocoele).
Rectum can herniate into the posterior vaginal wall. (rectocoele)
