this video was sponsored by kenhub more on them at the end of the video hello and welcome my name
is patrick and in this video i'll teach you some of my tips and tricks for remembering all of the
skeletal muscles of the pelvis that you would see in an anatomy class and to make this lesson
more manageable for beginners i'll present the list in smaller chunks of 4 to 8 muscles
you can find a list of the sections and time stamps in the description below with that out
of the way let's get into the muscles so this is going to be the shortest video in the muscle
series and while there are only a few muscles to learn i made this one its own unit because
i imagine the pelvic muscles slightly differently than the muscles of the arms and legs for instance
like instead of a clear elbow flexion or spinal extension muscle you have muscles that support the
pelvic floor or that promote blood flow during sexual arousal and that's really cool to me
the pelvis has skeletal muscles that interact with the urinary digestive and reproductive
systems which makes these muscles seem like magical and mysterious but at the end of the
day there's still muscles and like most of the muscles we've seen before the name of the muscle
usually tells us what the muscle does or where it is but since the pelvis is a big bone anatomists
refer to certain parts of the pelvis by their bony landmarks so let's review while the whole thing is
called the pelvis we refer to these big wings as the ilium or ilia if you're putting your hands on
your hips you're not actually putting them on your hip joint you're putting them on your ilia in the
front you have two pubic bones which are joined by a piece of soft tissue called the pubic symphysis
posteriorly you have these hollowed-out bumps called the ischium colloquially i've heard
these called the sits bones as well then this big centerpiece is the sacrum the base of your spinal
column and hanging off the tip is one of the remnants of our evolution the ancestral tailbone
called the coccyx once you know those bony landmarks you can start putting terms together
so this joint is the sacroiliac joint since it's the meeting place between the sacrum and the ilium
and that same strategy works for many of these muscles this first chunk of muscles
is collectively called the levator annie group which counter-intuitively doesn't lift the anus
necessarily it keeps your organs from falling out of your pelvis yes you have some connective
tissue there but these muscles are the floor of the pelvis hence pelvic floor muscles the center
piece is the pubococcygeus which connects the pubic bones in front with the coccyx in the back
it forms like a hammock-esque muscle with some important cutouts for an anus and genitals here
and here this little divot posteriorly isn't a cut out it's arched so that it can connect with
more surface area on the bone hanging out within that muscle is the pubo rectalis which originates
on the pubic bones and forms this structure called the puborectal sling around the rectum
if you've heard about the squatty potty and how squatting makes it easier to poop the
pipo rectalis is the muscle that supposedly puts a kink in the colon that's a whole other
video though the last muscle in the levator annie group needs a bit of introduction now i've spent
the last hour of video telling you about how intuitive these names are how if you just know
the bony anatomy or directional terms and you're set but here with less than 10 muscles to go the
iliococcygeus is the crack in the sidewalk that's tripping us up over the finish line
it starts off intuitive it's easy to see where it inserts on the coccyx but its origin is this broad
sheet of connective tissue called the internal obturator fascia not the ilium it's fine anatomy
i'm not mad i'm just disappointed if we move on we'll see another important pelvic floor muscle
the ischiococcygeus a long sheet of muscle that spans from each ischium to the coccyx in the
center although fair warning some textbooks just call this muscle the coccygeus which
i'm rapidly losing faith in traditional naming conventions for this group of muscles just do
your best something else to keep in mind you'll almost always get quizzed on these muscles from
a superior or top down view and from this angle you'll see some of the other hip muscles like the
piriformis posteriorly and the obturator internus anteriorly so if possible identify what those
muscles attach to because if they attach to the femur then they're not pelvic floor muscles and
they won't have pubo or coccygeus in their names but this next group the perineal muscles requires
the opposite perspective an inferior view also how do i put this if you're watching this in public at
a coffee shop or something just be aware of who's looking over your shoulder because the images
i'm about to show you are going to get a little spicy from this inferior view we can see some of
the structure of the perineum the area between the genitals and anus and a few of the muscles in this
area use the perennial region in their names for instance take a look at the superficial transverse
perineui you already know superficial it's closer to the surface and you already know transverse
it runs side to side instead of front to back the perineal points to its location between the
urethra anteriorly and anus posteriorly deep to that is the deep transverse perineui with the
same naming conventions also in the perennial area you can find muscles that plug into the genitals
but have different presentations depending on what kind of plumbing we're working with the first
the ischiocavernosus originates at the ischium and connects with the genitals if it's attached
to a penis it inserts on the crust or crura of the penis the part that attaches to the ischial rami
while the rest of the shaft mostly the corpus cavernosum dangles off for people with vaginas
the ischiocavernosus actually inserts on the clitoris and remember the clitoris is much bigger
than the small piece that you see on external diagrams as far as how to remember this muscle
the ischio root is easy enough to remember but the cavernosus relates more to its function
i'll explain during sexual arousal blood flows into the penis or clitoris enlarging either
when the ischiocavernosus contracts it squishes blood towards the distal part of the genitals
and compresses some of the veins that drain blood from the genitals which helps maintain an erection
or the swelling of the clitoris and that's a fun fact that you can bring up if you're ever like
in that situation but we still need to remember it for our exam i remember ischio cavernosus because
it connects the ischium to caverns of blood hence ischiocavernosus another muscle in that same area
is the bulbospongiosis which no is not a pokemon when it accompanies a vagina the pair of muscles
runs from the pubic bone in front along the sides of the vagina around penises it circles the bulb
of the penis which is close to the base i remember this one because it plugs into the spongy tissue
that gets erect during sex bordering the perineum you have two different tubes regardless of the
sex of your model and anus and a urethra obviously we don't want anything leaking out of those tubes
involuntarily so we have some muscles that squeeze those tubes shut these ring-like muscles are
called sphincters and we have a few the internal sphincters are actually smooth muscle under
involuntary control but the external sphincters one around the anus and one around the urethra are
skeletal muscles and are controlled voluntarily so when you're trying to hold in your poop you're
actively contracting the external anal sphincter most of the time your smooth muscle internal
sphincter does the trick on its own though so why do we have two well smooth muscle is much richer
in mitochondria so it can contract for long bouts of time without fatiguing we only use the external
sphincter when we're really trying to hold back the floodgates that's gross what makes this muscle
weird though is how it doesn't anchor into any bone it kind of blends in with the other pelvic
and perennial muscles but as far as the scope of this video just look for the bullseye it's easy
to find on the other hand the external urethral sphincter will surround the urethra for people
with penises the external urethral sphincter is right below the prostate at the base of the penis
for people with vaginas they have shorter urethras so there will be an internal urethral sphincter
right below the bladder and then right below that is going to be the external but no matter what
kind of genitals you have the internal sphincter is right below the bladder almost like you're
pinching a water balloon so now we've built a solid foundation for the pelvic organs to sit in
but there are still some genital specific muscles to consider if you have testicles you have a
cremaster muscle a thin layer of muscle that lines the scrotum and tucks the testicles into the body
if it's too cold this thing contracts and brings them towards body heat i remember this
one because it's main job is to turn up the heat on the testicles it's kind of like the cremaster
is trying to cremate the testes that's my memory device but i'm sure someone's already typing their
little jokey jokes into the comments section now these are just the tricks that i personally use
to remember these muscles but if you want another great resource for learning anatomy then you need
to check out kenhub i use them all the time when researching and writing these videos and for this
series in particular their written articles and atlas of muscles have been extremely helpful in
refreshing my knowledge of some of those deeper smaller muscles they've also got an enormous
library of in-depth videos about muscles histology vasculature nerves and everything else you'd need
to know in anatomy class all those beautiful illustrations that you saw in this video came
from them and in addition to their library of content i also love kenhub's quiz feature
they allow you to build custom quizzes with different difficulties and they give you feedback
so you can figure out where your weaknesses are you can use most of kenhub's features for free but
if you want full access to all of their learning content and quizzes then go to k-hub dot me slash
corporis to get 10 off your subscription they've also got a no questions asked seven day money back
guarantee so you can try out the premium version for seven days and if you don't like it get your
money back if you want to see the next video in the muscle memorization series then check out this
playlist here otherwise subscribe leave a like on the video have fun be good thanks for watching