okay so this is a tutorial on the pelvic floor so what we're looking at here is a superior view into the pelvis and you can see these muscles which make up the pelvic floor at the bottom of the pelvis so I've got the femurs in here because I've included the muscles of the walls of the pelvis so you've got the piriformis muscles attaching to the sacrum into the greater trochanter of the femur and you've got the obturator internus muscles which you can see here if I rotate down to the back you can see the tendon of the obturator internus muscle attaching to the femur so those two muscles make up the walls of part of the walls of the of the pelvis so the pelvic floor separates the pelvic cavity above from the perineum below and it consists of the pelvic diaphragm and then you've got the perineal membrane and the deep peroneal pouch so the word pelvic diaphragm is often used interchangeably for pelvic floor but in this tutorial I'm going to talk about the pelvic diaphragm in relation to two specific muscles and then I'll go on to tell you about the perineum membrane and the deep peroneal pouch so these three structures combined make up the pelvic floor so to begin with I'm going to talk about the pelvic diaphragm so the pelvic diaphragm is this dome shaped set of structures which we're looking down that and it consists of the levator Ani muscles on either side so you've got this midline graph this ligamentous midline where the two halves of the levator Ani muscle attach and you've got the Cox Egeus muscle which is this muscle here so I've just isolated the the pelvic diaphragm muscles and you can see the shape of them here it's like this this bowl shape of muscles so ignore this extension up here as the the muscle doesn't actually extend this far up so just bear that in mind so it has its anterior attachment on the posterior surface of the pubis here and then it attaches along the fashion of the obturator internus muscle and then at the back it attaches to the coccyx and it meets in the midline to form this midline RAF so this is where the the levator Ani meets in the blind posterior to the anus which is this aperture here so anteriorly you can see that the levator Ani muscle has this defect it's got this u-shaped defect and this is called the urogenital hiatus and this allows the urogenital apparatus to pass through the pelvic floor into the perineum below so in males you get the passage of the urethra and in females you get passage of the Jerusalem and the vagina through this urogenital hiatus and as you can see the muscle consists of various different fibers so you've got these loops of fibers which loop around various structures so the levator Ani muscle is typically thought of in terms of three sets of fibers so you've got the pubococcygeus which attaches from the bony bit of the pubis and extends back to the coccyx so you've got a coccyx set at the back here and then it's got some anterior the anterior fibers of the pubococcygeus actually loop around the prostate in males and the vagina in females so you've got these anterior fibres which are divided and loop around the prostate in males forming the levator prosthetic or the pubic prostatic as' and in females it loops around the vagina forming the pupa vaginalis and then in the midline as I mentioned before connecting from the coccyx down to the anus so remember this is the aperture for the anus so connecting from the coccyx to the anus you've got this midline of laughs this ligament which is called the NO coccygeal ligament or a no coccygeal body and then the next part of the levator Ani muscle is this peu boat wreck talus muscle so I'm going to draw this on in green outline in green and this forms a sling around the distal end of the gastrointestinal tract so around the sort of anus and rectum and the anal rectal junction so you've got this sling of muscle from the Veda a knife forming around the anorectal junction so these are the intermediate fibers of the levator Ani and they again originated on the pubis and they have the important function of maintaining this a no rectal angle so they keep this angle of 90 degrees which closes off the anal canal and I'll come on to talk about this in a moment and then we've got the posterior fibers of the levator Ani muscle and these are called the iliac coccidia muscles or fibers so you've got these which I'm outlining in purple so those are the three collections of fibers which make up the levator Ani muscle so this muscle forms the bulk of the pelvic diaphragm so just to quickly recap the levator Ani is composed of these three collections of muscle fibers and if we rotate the model around you can see the origin of the levator Ani on the posterior surface of the pubis and then it's got this origin along the border of the obturator internus muscle so covering the obturator internus is this fashio and you've got this thickening so you can see this white thickening this is a tenderness thickening called the tenderness arch and this is the thickening of the fashio where the levator aina takes part of its origin and then over here we've got the ischial spine so along this line from the body of the pubis along this tenderness arch to the spine of the ischium the ischial spine the levator Ani takes its origin and then it inserts on the coccyx and in the midline at this anal coccygeal ligament so if we just rotate to an inferior view you can see these muscles taking their attachment on their little coccyx and you've got this perineal body which is a fibromuscular connective tissue node which joins the perineum and the pelvic floor and you've got some convergence of the levator Ani muscles on this node so the function of the levator Ani muscle is to support the pelvic viscera and it keeps the rectum and vagina closed so it has this kind of sphincter closing action on the rectum in the vagina and importantly it resists wises in intra pelvic pressure during any straining so for example during coughing when the abdominal muscles increase the intra pelvic pressure it resists this rise and prevents anything being evacuated from the digestive tract so one thing I mentioned was that the pubic Tallis maintains this anal rectal angle so you've got this angle between the rectum and the anal canal and the pubic talus loops around this and and it keeps this angle so by maintaining this angle it sort of forms this valve which stops the anal canal filling with feces from the rectum so when this muscle relaxes and releases its tension on this angle the angle between the rectum and anal cab canal increases and it becomes more like this so then you don't get this pinching off of the anal canal and feces can flow from the rectum into the anal canal so this is important in defecation so you need to be able to relax the pelvic diaphragm muscles in particular the pubic Tallis portion of this muscle in order to relax this anal rectal angle and prevent shutting off of the anal canal so the other muscle of the pelvic diaphragm is the suggests which you can see here on either side so this muscle lies over the sacral spinous ligament so if I rotate around to the back you can see this ligament connecting the sacrum to the ischial spine so it lies over the sacred spinous ligament and it forms the posterior part of the pelvic diaphragm so originates on this ischial spine and it inserts laterally on the coccyx and the adjacent margins of the sacrum so if I just really take down to the back you can see it's an insertion along the margins of the sacrum and the coccyx below so this muscle functions to support the pelvic floor and it's innovated by branches from the anterior Ram eye of s4 and s5 so the levator Ani muscle is actually innovated by branches of the pudendal nerve from roots s2 to s4 so you've got that useful mnemonic s two three four keep off the floor so it describes kind of the function of the levator Ani muscle so we've talked about the pelvic diaphragm now in quite a lot of detail so the next part of the pelvic floor is the perineal membrane and the deep peroneal pouch