Lecture 18 - Pelvic muscle and fascia Flashcards
The obturator foreamen is closed off by what?
obturator membrane - leaves only the obturator canal
where are these 3 muscles located:
obturator internus
levator ani
piriformis
obturator internus - lateral wall
levator ani - pelvic floor
piriformis - posterior wall
where does obturator internus arise from?
internal surface of obturator membrane - extends to the margins of the obturator foreamen
exits via the lesser sciatic foramen - converges and goes to the gluteal region
Piriformis arises from the middle 3 pieces of the sacrum on the _____ surface
anterior surface of the middle 3 pieces
where does piriformis exit?
via the greater sciatic foramen - heads for the greater trochanter
levator ani is basically the..
pelvic floor
levator ani is suspended from the side wall - what is its lateral origins (3 parts)
A thickening of the fascia overlying obturator internus
With levator ani, there is a large opening _____ -_______to the region below called the perineum
There is a large opening antero-medially to the region below called the perineum
half of obturator internus is above ___ ___
levator ani
other half is below in the perineum
The rectum becomes the anal canal at the level of the ___ ___
pelvic floor - lev ant. interdigitate at the midline rafe, at the ano-rectal junction
what are 2 componenets of levator ani?
pubicoccygeus
iliococcygeus
pubicoccygeus arises from what?
pubic bone - most anterior part
pubicoccygeus has a sling that extends where? whats it called?
why is it important?
from the pubic bone, around the anal- rectal junction and blends with the fibres of the ano-rectal junction
defacation can only ocur when puborectalis is relaxed
In the male/female what is the most anterior slight for pubococcygeus?
pubo-prostaticus
The non-slight parts of pubococcygeus (the hammock) is from where to where?
side wall of the pelvis and insert on the ano-coccygeal rafe - as we would expect from levator ani
how is pubococcysegeus delineated from iliococcygeus?
pubococcysegeus is the ANTERIOR fibres, overlaps iliococcygeus when you look down on the pelvic floor
Pubo.c has the slights
ilio.c is a simple hammock
iliococcygeus+pubococcysegeus =
LEVATOR ANI (LIFT THE ANUS)
What muscle extends from the ishial spine to the coccyx/sacrum?
ishiococcygeus (ishio.c)
What is the significance of ishiococcygeus ?
disappearing from the species - used to wag tail
not part of levator ani because its not functional in lifting the anus
what are levatorani’s functions?
increasing intra abdomino-pelvic pressure alongside with the diaphragm - assists all evacuation processes/
To maintain and support the position of pelvic viscera
rotation during childbirth
The parietal fascia is not as dense over which muscle in the pelvis, why?
levator ani - it has to lift up
the parietal fascia of the pelvis is a continuation of the….
anterior abdominal wall (fascia transveraslis anteriorly, posterior ado. wall posteriorly)
The visceral fascia in the pelvis is continuous with..
the extrperitoneal fat layer of the abdomen
There are thickening (ligametns )visceral fascia around what in the pelvis?
vessels and nerves
condensation of visceral fascia - when they become engorged - create strong support
The nerves and vessels are “glued to the muscle” by…
fascia
Obturator nerves comes off the _____ _____ and now crosses the ______ _____and runs on the side wall, through the _____ canal
Obturator nerves comes off the lumbar plexus and now crosses the pelvic brim and running on the side wall, through the obturator canal
What fascia does the obturator nerve supply?
parietal - pain referred to medial side of the thigh (just above the knee)
The nerve supply to the peroneum is the
pudendal nerve - really imporatnt branch of the sacral plexus
From the internal iliac artery there is what brancheds?
posterior and anterior branches - give give rise to parietal branches for the wall and visceral branches for the viscera
