- Hello, massage nurse.
Today, we're going to be doing lesson 11,
which is the muscles of the trunk
and vertebral column movements.
Today I only drew the anterior part,
which is the four abdominal muscles,
because I'm doing my best to kind of break it up
and make it a little bit easier for the students.
So you've got your rectus abdominis,
your external oblique, internal oblique,
and your transverse abdominis.
And we do have an external
and internal obliques on both sides.
I just do it separate so you could see the different fibers.
So let's start talking about the transverse abdominis,
which is your deepest muscle.
It's, you know, posterior to these three muscles.
So it's all the way to the back.
You know, it holds in your abdominal cavity.
You know, it holds all the internal organs
and you can see it starts from the,
you know, from the seventh rib
and then, I drew it on both sides.
It's the brown one that I drew on both sides
and it goes, you know, horizontally.
Okay.
And then you have your external oblique
and your external oblique fibers go diagonal, this way.
It's like when you put your hands in your pockets,
that's your external oblique.
If you put your hands in your pockets,
they don't go all the way to the middle.
Usually the hands go like, you know, like around right here.
Your external oblique is the same way.
It doesn't go all the way to the middle.
It goes right here just to the side
of the rectus abdominals.
And then your internal oblique,
the fibers go the opposite way.
So if you put your hands in your pocket this way,
then this is the external, you know, oblique,
the internal oblique crosses that.
Their fibers go crosswise because this is, you know,
a natural girdle that we have
to keep our abdominal cavity inside.
This is what is very important for you guys that,
you know, that want to build a six pack and want to have,
you know, strong core muscles,
that you also work your internal and external obliques.
Okay, they all originate here, you know,
on the iliac crest and the pubis,
the rectus abdominis originates in the pubis
and inserts all the way up here
to the fifth through seventh rib,
right underneath the xiphoid process from the sternum.
Most people think that we only have a six pack,
that there's six sections,
when in reality, we have eight, eight to ten sections.
However, you can only really see six and they are split,
you know, they connect right here to the linea alba
which is right straight down the middle.
And then you have the aponeurosis
where the other muscles, you know, connect to it.
You know, the aponeurosis, remember,
it's a flat sheet tendon.
So you've got very strong tendons, you know,
that attach it and connect it.
And I want to show you guys, you know,
like for the different movements.
So flexion, if you flex your torso,
you know, you're bending forward,
the muscles, you know, the origins down here,
cause it's flexing you, it's flexing your abdomen.
And then the back part will be the ones
that pull you back up.
Okay, I didn't draw the ones in the back.
I just wanted to show you flexion
and it takes these four muscles.
So flexion would be the psoas major.
If you guys remember from the previous lesson,
the psoas major is the main hip flexor
and that one originates from the T12
to lumbar 1, 2, 3, 4, 5,
and it crosses diagonally and inserts
at the lesser trochanter of the femur,
so that one's involved in the flexion of the torso too,
and then the external oblique, the internal oblique
and the rectus abdominis,
all of those muscles are for flexion.
Now for extension, I'll talk about that in the second part,
and then rotation, so when you rotate,
that is the internal oblique, the external oblique
and the transversospinales from the back.
So those three muscles are for rotation.
And then for lateral flexion, when you go sideways,
that will be the rectus abdominis,
the external oblique, internal oblique,
quadratus lumborum, semispinalis and multifidi,
and erector spinae, those are also on the back.
So it takes the anterior and posterior muscles
to really help you do any movement.
And I've always taught my students
that origins are the least moveable
because the insertion always moves towards the origin
and you have the rectus abdominis straight down the middle
and you have two points and you're trying to figure out,
well, which one is the origin, which one's the insertion,
because they're both in the mid-part of the body.
So now you've got to make your brain think a little bit
and figure, okay, what does this muscle do?
It flexes, right?
So it originates here at the pubis
so in order to flex, it's got to pull down.
So the inferior part would be the origin, right? Correct?
Because this part is pulling in order to flex.
The same thing with the external oblique here.
And, you know, they both are right here at the iliac crest.
So, and this one also gets close to the pubis.
So they pull down in order to flex.
So that's how you know the difference
between the origin and the insertion.
And I also want to tell you guys
that we found a couple of mistakes.
I usually use two references.
My app to the "Trail Guide to the Body" and the book.
And I found that they said,
you know, the rectus abdominis, they had it different.
You know, they had the origin as the insertion
and then the insertion is the origin in both different apps.
So the reason I'm letting you guys know is
because I have found mistakes in books.
I have heard doctors make mistakes.
I make mistakes.
I do my best to correct them and I always tell you,
the reason I'm telling you is because I want you guys that,
if you are sure that, you know,
this is the way you learned it, you know, check it out,
look up your sources, you know, find out if, you know,
if somebody along the way has made a mistake.
And so, I mean, that's just what I do
because we did find a mistake today.
You know, so anyway, I wanted to show you guys,
these are the abdominal muscles and there's four layers.
The transverse abdominis is the deepest
and the rectus abdominis is the most superficial.
We have eight sections
and we can only really see six in which,
what makes your six pack.
They're very important, you know,
to keeping your core strong so that you can,
you know, be strong and keeping your gut in.
And we have a natural girdle.
This is where girdles come from, guys, you know,
they've looked at our natural girdle, you know,
the internal, external oblique really keep your abdominal,
you know, internal organs and, you know, it's strong.
So for you, that you work out,
make sure you work out the external obliques,
internal obliques and your rectus abdominals,
and then you're gonna look really flat
and you don't need a tummy tuck. (laughs)
Anyway, guys, I hope this helped you.
This is going to be your homework to draw the four muscles
of the, you know, of the trunk.
Next time we'll do part two.
This is lesson 11.