Muscles of the Trunk (Intro to Functional Anatomy)

Muscles of the Trunk (Intro to Functional Anatomy)

We’re going to go superficial to deep. So
let’s start with the external obliques. Now your external obliques fiber
direction, which way does it go? This way right. The way your fingers would be if
you put your hands in your front pockets. So you guys can write external obliques
front pockets, to help you guys out a little bit. How many of you guys look at
pictures of bodybuilders and fitness models, and you know you’ve seen a muscle
and fitness magazine or a shape magazine, and people get all striated in here
right, you see the lines. Which direction do those lines always go? Right because
your external obliques are external right, they’re the ones that are most
superficial that’s what we’re seeing. So if the fiber direction is this way
alright this muscle goes like this, what joint actions is it going to cause? Yeah which rotation is it? If this muscle shortens what’s gonna happen to
my spine? It’s going to rotate this way? Alright if this muscle shortens it’s
going to twist me this way right, which would be contralateral rotation. So we
got external obliques contralateral rotation, what else might
they do? Okay so we got we got the obliquity thing, I told you guys
muscles with a diagonal usually do rotation, we got rotation out. There’s got
to be a couple other things this muscle will do though. It’s going to help with
flexion right, because the obliques do lie in front of the lumbar spine right, this is
the joint that they cross there in front of it. So external obliques flexors of
the spine. I’m gonna say yeah. What else might they do? Lateral flexion. How many
of you guys think lateral flexion? Yeah I mean how do people try to work their
external obliques a.k.a their love handles, because they’re
trying to spot reduce the fat over their external obliques which absolutely
doesn’t work, and then they do an exercise which is kind of ridiculous we
already talked about this yesterday. They do this one right we talked about this.
Well your external obliques actually are not your primary lateral flexor of the
spine, but do they lie lateral to the spine?
Sure so they’ll definitely help a little bit, it will definitely help. Now the other thing you have up on that
chart there and this is more just some extra information for you guys, we were
talking about connective tissue this morning right, when you open up a cadaver
you don’t see all these pretty red muscles, you see a lot of white
connective tissue that is especially true in this area. The most superficial
thing here on your six-pack is not your rectus abdominis,
but this abdominal connective tissue. And you guys see a little evidence of that
because what actually makes the 6-pack? You have the Linea Alba which is
the connective tissue in the middle and then all of this these transverse little
separations, which are also made of connective tissue. They’re probably there
because connective tissue with its rigidity and strength, probably improve
the overall strength and ability for the rectus abdominus to prevent what? What
don’t we want to do with the lumbar spine? Forceful hyperextension right. So
we have a nice nice bit of connective tissue here to help help the rectus
abdominus to its job. Just reinforce it a bit. I think that’s one of the next
muscles up here, yeah rectus abdominus. This one should be pretty easy for you
guys right. Rectus abdominus runs, which way does its fibers run? Up and down. So it runs up and down in front of the
spine. What plane do you think it’s probably going to work best in? It’s a
sagittal plane muscle, being that it’s a sagittal plane muscle and it’s in front
of the spine, what do we think it’s going to do as far as joint actions? Flexion. I always love every once in a while I get these
calls from like a writer for like one of the magazines or whatever, and of course
what do they always ask what’s the best exercise for the abs. And of course what
are they talking about when they say abs rectus abdominus, and my answer is always
the same. What’s the best exercise for the rectus
abdominus? Flexion. Do you have anything other than flexion? No that’s what the
rectus abdominus does well. What else could the rectus abdominus do a little
bit of? Does anybody know? Like think about your tilts, you remember your
pelvic tilts right, it’ll do this. Isn’t this still spinal flexion though? Yeah
you have to do spinal flexion to posteriorly tilt. So they’ll be like so so
the the rectus abdominus just is flexing? Yeah and it’ll posterior tilt your
pelvis. But what do you mean? Oh you can do a crunch, or you can do a reverse
crunch. I guess isometrically you could do a
plank. Would anything else really affect the rectus abdominus all that much? No. No
the truth is when we look at EMG studies guess what has the highest activity for
the rectus abdominus? Crunches, reverse crunches, like those things that actually
do the action of really not that complicated right. What keeps most people
from having a 6-pack, is it the exercise they chose?
It’s diet. How do you get a six-pack? Shut your face, move your glutes right. You want to get that tattooed, that was
actually the original title of my first book, and the agents were like you can’t
have shut your face and move your ass as the title of your book, that’s not going to
work, and I was like why not. Internal obliques, internal obliques. So we talked about
external obliques being this way right, those are the muscles you can see, it’s
fiber direction as if you put your hands in your front pockets. Guess which way
the internal obliques go? This way all right. So it’s like the direction your
fingers would be if you put your hands in your back pockets. You guys cool with
that. Internal obliques, so which way, what what
joint actions are we looking at? Rotation. We got the obliquity, we know it’s on a
diagonal. We know it’s probably going to contribute to rotation. You got to tell
me ipsilateral or contralateral though. If it’s this way and it’s going to shorten,
and you guys see how that would shorten. Exactly exactly ipsilateral, all right.
What else might it do? Lateral, lateral flexion. Yeah it’s on the side of the,
it’s on the side of the lumbar spine. I’ll say lateral flexion. You guys think
this can contribute to a sagittal plane motion, like you can contribute to
flexion or extension. Flexion, why flexion? It’s still in front
of the lumbar spine right. Now remember your lumbar spine is way back here,
so all these anterior core muscles that we spend so much, that we give so much
attention right in the popular media, they’re pretty much all flexors. Everybody’s got this. So yeah so this does get a little
confusing, the contralateral versus ipsi- lateral thing. So if you guys, let’s pick
two points right. These both, both these muscles have pretty broad origins, pretty
broad insertions, but let’s take the external obliques first, since we
covered those first. Put one finger on your ASIS okay, and then put one finger
back on your ribs all right. Now try to bring those two fingers closer. Which
which direction did I rotate? I ended up rotating a little bit to the left right,
so that’s rotation to the opposite side. the muscle is on. Contra means against,
right against our away, so that’s contralateral rotation. Now let’s do the
same thing with the internal obliques. Let’s pick a point, let’s let’s pick this
little angle of your ribs here right, and all the sudden changes let’s do that one.
Point on your posterior ilium and now try to bring your fingers closer
together. Yeah you guys see how that works. So now we have a muscle on the
right is rotating me which direction? To the right. So that’s the same side that
would be ipsilateral. You want to totally freak yourselves out? When I rotate to
the left, which oblique am i working? Oh yeah right external oblique right, but
my left internal oblique. Muscles work best in the direction of their fibers.
Isn’t it kind of true that if I rotate this way, that this external oblique and
this internal oblique kind of have the same fiber direction, and then if I go
the other way its. Transverse abdominus, how many of you guys have heard of this
muscle? Definitely a muscle a lot of people talk about. Definitely a muscle of
a lot of controversy. But the transverse abdominus is an interesting one, because what joint action based on its fiber
direction do you guys think this muscle does? Which is the fiber direction is is what?
It’s transverse right, that’s why it’s called the transverse abdominus because its
fibers are orientated transversely. Its origin and insertion is basically the
thoracolumbar fascia. It’s a little different than that in
textbooks but you guys get what I’m saying.
The attachment goes from here, it wraps all the way around and goes right
back into here. So when it contracts what actually happens? It’s basically your
weight belt right. You guys remember like, you guys seen the big guys with like the,
and they do, they have the big weight belts and they it’s like pull them as
tight as they can before they get underneath something like a squat, that’s
what this muscle is supposed to do. it’s supposed to cinch everything up ,which
what that ends up doing is increasing intra-abdominal pressure. It also tightens this piece of fascia
back here right, this thoracolumbar fascia, it pulls it like this really
tight. Is that gonna help stabilize my lumbar spine? A little bit – yeah. It’s
like having guy wires on each side just getting pulled really really tight So
it’ll increase stiffness in the thoracolumbar fascia. TLF not to be confused with the TFL
right, we think that these two things together increase the stabilization of
the lumbar spine so that make sense. Now there’s some varying opinions on how
effective that is, but if you guys want to write down a
couple researchers there’s, I know some of you guys are way into the core
you got Richardson Hodges and Heinz, so I’m gonna put Richardson et al. Then
there’s another guy named McGill who has a little different theory, and then
another guy named Liebenson who has more research and a different approach. A
lot of stuff out there. You guys heard of your multifidi. Yeah so your multifidi are
interesting little muscles, they’re fairly deep and they go from spinous
process to transverse process. Spinous process-transverse process, spinous process-transverse process. Very segmentally. They’re on the back of the
lumbar spine so what joint actions do you think they
do? Extension, sure they have an obliquity so what else might they can
contribute to? Rotation. So we got extension, rotation, and what we
believe that’s really important about these muscles, these aren’t the big
extensors of the lumbar spine right. These little tiny muscles that you see
in those pictures, but they have something different than the other
extensors we’re about to talk about, which is they’re segmentalIy innervated.
They cross only a couple segments at a time, so we think they’re important for
what we call segmental stabilization. Which is basically, if you thought of
your lumbar spine like Jenga, you guys know the game Jenga, right you got to
keep all your bricks stacked up, So if these were the bodies of my lumbar
vertebrae right, I got my five little blocks there, what we think these muscles
do is when movement or pathology or dysfunction cause our blocks to be this
way, it might be these muscles that aren’t
doing their job. When movement causes us to do something like that, one of our
blocks to move out of place, we think that these muscles doing their job will
cause these blocks to do what? Straighten back out again, does that make sense .So
your multifidus basically keep your blocks aligned. You
guys ever heard the term segmental stabilization? No. You would. That’s
segmental stabilization. All we’re talking about is keeping our block
stacked on. It’s a pretty bad thing right, if one block slides over the other
starts moving out of place, instinctively guys do you think that’s a good thing? No
probably not. So we think the multifidi have a big role in this. This is
the joint actions they’ll help with, but this might be their more important
function. Just like when we talked about the rotator cuff, we talked about the
rotator cuff doing external rotation, internal rotation, abduction. But what was
their important function? Dynamic stabilization of the shoulder right. Same
thing with the multifidi and the TVA, they have an action, but their
function-stabilize the lumbar spine. Alright let’s look at another big mover. No no so the multifidi are very deep and
lie right against the the facet joints of the lumbar spine. Your TVA actually
more or less stops at the thoracolumbar fascia. Your multifidi there’s layers to
the thoracolumbar fascia it lies with, sandwiched between a couple of those
layers. Does that kind of make sense? I got a bunch of pictures online, if you guys go
to those muscular Anatomy articles, you look up multifdi, you look up
transverse abdominus; I have tons and tons of pictures showing like
cross-sections and stuff, so you get a good idea of where all of this stuff
exists relative to something else. The erector spinae. Alright I’m going to ask a question
knowing that I’m probably going to get twelve-year-old laughs out of it, what
does it mean to erect something? To stand it up right. So if my erector
spinae will erect me or stand me back up and I started down here,
what joint action is that for the spine? It’s extension.
I like the erector spinae. I like the little muscles of the back the erector
spinae, even the multifidi, I just like the way they’re shaped, I think they’re
shaped cool, you know what I’m talking about? Looks like an upside down Christmas tree. Alright so if only this side of the
erector spinae contracted, what would happen to my spine? Yeah contribute just
a little bit to lateral flexion. You guys realize how long your erector
spinae are? Yeah exactly, so just keep in mind all the way down to your sacrum, all
the way up to your mastoid process, depending on which of the erector spinae
muscles we’re talking about. Another thing to keep in mind, something once you
guys start digging a little deeper into your Anatomy is, is there one erector
spinae muscle? Yeah, is there only one erector spinae muscle? Yeah there’s
actually three, and they all do a slightly different thing. So you have
your spinalis, your iliocostalis and your longissimus. You know at this
level your okay calling it the erector spinae. Like I said your next level once you
guys get into graduate school, you start tearing things apart, maybe do some
cadaver work, you’re gonna start needing to know all of the different erector
spinae muscles. How many pushups per ring? I’m going to make
you start dancing if it happens again. You have to dance until you get your
ringer to stop. Alright so what do I mean by bilaterally and unilaterally, great
question. So bilaterally means what? Both sides. If both sides of my erector spinae
fire at the same time, what are they going to do? They’re going to pull down on my
spine, pull down on my ribcage and I’m going to do
this. But if only one side unilaterally right, like unicorn one horn
right, unilaterally pull down, what’s going to happen to my spine? This. Well we
could see, this is where the layers come in right, if we start dividing out these
erector spinae muscles we’ll see that at least one of them will contribute a
little bit to rotation, and that’s one of the larger erector spinae muscles being
your iliocostalis. Usually when you see that word cost, C O S T, costa, costol right
it has to do with the ribs. Iliocostalis is the big erector spinae muscle which
goes into the ribcage, and it probably can cause a little bit of that rotation. Yes yeah it kind of looks like a
Christmas tree depending on which one we’re talking about, but it’ll be like
the iliocostalis does this right. The spinalis just goes from spinous
process to spinous process like this. The function of this class guys is to is
to get down the joint actions. I’m excited though because you guys are starting
to ask deeper and deeper questions. But as I kind of mentioned earlier when we
were just warming up and going through our Q&A today, this doesn’t ever stop.
It’s one of the exciting things about getting into this field is, like there
are, we keep calling rabbit holes right. There are rabbit holes to jump down
forever, you find something you’re into you can just keep going, as I mentioned
those those functional Anatomy articles that I have up on my site, talking like
six seven pages of text on one muscle, and then pictures, and videos and
illustrations and diagrams, and research. Depending on what muscle you talk about
you may have hundreds of research studies to look at. Fun stuff. Quadratus
lumborum, how many of you guys have heard of this
muscle before? Cool, so this muscle goes from my 12th rib to my posterior ilium. The
thing I want you guys to keep in mind though, this isn’t a superficial muscle
like out here, it’s a twelfth rib to posterior ilium
with some connections into these transverse process; it’s actually a very
deep muscle, comparatively. Your erector spinae are on top of them, your
latissimus dorsi, transverse abdominus, internal and external oblique, on top of
them. So it’s fairly deep it’s like just like this. What joint action do you think
it’s going to cause? Lateral flexion. Anything else? Where would it have to be
to cause extension? They’d have to be here
right, they’d have to be somewhere behind the lumbar, at least on the spinous process,
be behind the bodies of the vertebra, this is right here. No rotation, what
would it have to have to do rotation? Some sort of obliquity, come forward a
little bit, this is this is lateral flexion. In fact your quadratus lumborum
is your primary lateral flexor. This exercise -quadratus lumborum exercise, a
little bit of oblique but quadratus lumborum. Sure quadratus lumborum is very important for stability. It is one of those muscles we’ve kind of
talked about though like the iliacus, that has a propensity to get tight. If
the quadratus lumborum got tight, what is that going to do? It could pull you
this way if it’s one side, if it pulls on both sides what’s it going to do? Yeah it
could, it could start to compress and give you a little soreness, eventually
contribute to maybe some pain and dysfunction, you guys see how that would
work. I’m not, I totally agree that the quadratus lumborum is important to
stabilization. Is this a muscle that I’m going to write down and exercise for in
a routine? Probably not. I don’t think this is something we have to
individually strengthen, and I think targeting it too hard
might help contribute to that cycle of this muscle getting a little overactive,
a little tight, and contributing to some of that low back pain that we see
in so many individuals. This exercise we’d never give anybody, and not just
because it makes people look silly, like they’re trying to impersonate a wheel
wobble, I think it contributes to low back pain. Oh you guys didn’t think you’d
go a whole hour without doing a graph did you? You know what that means though,
we just did, you guys just finished all the muscles for functional anatomy one.
So the one thing I think I mentioned there guys is the TVA, although it will
play a role in all joint actions, it doesn’t have a joint action so it’s not
going to end up on this graph. Don’t forget about it though, that’s what that little
box at the top says. Action, plane, muscles, exercise that includes that joint action.
So this one’s a little bit more like the scapular graph we did. Whats that? TVA what about it? TV, TV-transverse
abdominus. I’m sorry did I not define that? TVA, yeah TVA is transverse
abdominus. Occasionally you’ll see it as TA, what’s the problem with that
one? Tibialis anterior. Your transverse abdominus right, does that make sense? It
just wraps around like this. he hasn’t, he yes exactly.

29 Replies to “Muscles of the Trunk (Intro to Functional Anatomy)”

  1. New Video from Dr. Brent Brookbush: Trunk Muscles (Intro to Functional Anatomy)

    #BrookbushInstitute   #BrentBrookbush   #DrBrentBrookbush   #Brookbush   #DrBrookbush   #FunctionalAnatomy   #Anatomy   #AnatomyGeek   #AnatomyisAwesome   #AnatomyClass   #AnatomyLecture   #AnatomyStudy   #TrunkMuscles   #RectusAbdominis   #ExternalObliques   #InternalObliques   #Obliques   #ErectorSpinae   #QuadratusLumborum   #QL   #TransverseAbdominis   #TVA  

  2. Great stuff Brent. I am quite a frenetic tutor myself and it's so refreshing to see how calm you deliver your lectures. Fantastic pointers for me to pick up on.

  3. Hey Brent, with regard to the erector apinae muscles, would you recommend not strengthening spinalis and illiocostalis and logissimus such as spinal extensions due to most individuals having an ATP, rather just lengthen them and leave them alone in regards to isolated activation. Great video and thanks again

  4. New comment on the videos: Muscles of the Trunk (Intro to Functional Anatomy)

    #BrookbushInstitute   #Brookbush   #DrBrookbush   #SportsRehab   #SportsRehabilitation   #Orthopedic   #OrthopedicPhysicalTherapy   #OrthoPT   #SportsPhysicalTherapy   #SportsPT   #SportsChiro   #SportsDC   #SportsChiropractic   #Sportschiropractor   #AthleticTraining   #AthleticTrainer   #CertifiedPersonalTrainer   #PersonalTrainer  

  5. As a LMT, it would of been cool if you went into a little bit of origins and attachments. It was a nice refresher on actions though.

  6. Great video, as you said QL is the primary lateral flexor . Which come second, external oblique or internal oblique?
    If some one has left lateral flexion ,would you recommend lengthening the left side ?
    Many Thanks

  7. Question re: "Who is the second strongest lateral flexor? in the comments section of the video: Muscles of the Trunk (Intro to Functional Anatomy)

    #BrookbushInstitute   #Education   #Training   #ContinuingEducation   #ConEd   #OccupationalTherapy   #OT   #PhysicalTherapyAide   #PhysicalTherapyAid   #PhysicalTherapyAssistant   #PTA   #Anatomy   #FunctionalAnatomy   #Core   #Trunk  

  8. Pull ups in fact have shown to have greater activation than sit ups, crunches, and leg raises in EMG studies due to the retus abdominals performing isometric to keep the torsal and legs stable.

  9. Based on origin and insertion, your description between ~1:00–2:00 and ~11:00–12:30 minutes does not make sense. You moved the origin of external oblique closer to internal oblique. Why would the external obliques not cause ipsilateral rotation?

  10. I'm taking NASM CPT next week and discovered your channel few days ago…think I will be clearer understanding the syllabus in the textbook when i get em on hand (since I watched 5-6 vids from you already) Thanks Brent !

  11. I've been a massage therapist for the last 13 years and man Brent knows what his doing, wish I could've have his lectures at the beginning of my career.I love the way he interact asking questions all the time.
    There's a lock of origins and insertion of the muscles in this video but the demonstration of the action is good, and a nice refresher. Thank you for sharing

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