- Lesson details
In this series, artistic anatomist Rey Bustos brings you a fun, unique introduction to anatomy of the human body. In this third lesson of the series, Rey shows you anatomy of the back. Rey will begin by lecturing on the blackboard, breaking down each bone, muscle, and tendon of the region. Next, he will use photo references to diagram key areas of the back and some of the shoulder. Finally, Rey will end the lesson by doing an ecorche drawing demonstration over the photo references.
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the beltline now. As always, I’m going to take you to the classroom, and I’m going
to be hitting that blackboard and images. The whole nine yards. You’re going to love
this. We’ll be doing the back muscles and the triceps and some of the shoulder muscles.
Let’s get to it.
as easy as possible for you. One of the things I know I can tell you that when I was a student
the back was one of the most complicated areas. It was kind of like going through a jungle
without a map. I really did not have any idea of what was going on in the back area for
a long, long time. Since I’ve been teaching so many years I have learned to simplify it
so that people don’t go to the same torture that I went through just trying to figure
things out. You look at a back by Peter Paul Rubens or Leonardo da Vinci or Michelangelo,
and these things just look like who knows what’s going on back there.
But now that I know a lot about the back, I understand what they’re doing and how
they make all the muscles come to the surface. Unlike the front. The front muscles, the superficial
muscles are the ones that we recognize and see even though there are layers to the front.
The back is layered, but the problem with that is that with every movement muscles go
in and out, in and out. The deepest muscles are going to be the most visible in many poses.
You put your arms up in the air, and all of a sudden all you see are the deep layer muscles.
On leaner people sometimes the deeper muscles are more apparent than the superficial muscles.
Okay, so what I’m going to do is I’m going to first draw for you a back.
Let me just throw in our little model here and start with this. So now, here is the base
of the skull. So what I’m going to do is I’m just going to go down.
Down, down, down the vertebrae.
Just like that. I’m going to locate C7 because it’s such an important bony landmark. C7.
I think all of your teachers have mentioned C7. It’s the bump on the
back of your neck, roughly where your tag is on your T-shirt. Then you have your rib
cage, which is roughly 1-1/2 times the size of the head, just to keep things simple. It’s
roughly like a shape kind of like this. Dinging out like your little floating ribs, etc. It’s
important to note the direction of the ribs themselves. They do this. They have a way
of falling laterally like this towards the ground. I’m just going to take my finger
and just kind of finish this off so it looks kind of like a little x-ray. Obviously, we’re
not going to be using the whole skeleton. Over here what I’m going to do is probably
keep this a little bit deeper, like deeper muscles, and seeing if that helps you.
Like this, like this.
You have seven neck bones ending with the most pronounced one. Then the vertebrae just
below that are the ones that hold the ribs. So I’m going to adjust that just a little
bit. Here is that nice bony landmark again. I don’t want that to disappear. C7. Okay,
it’s the end or the last of the neck vertebrae. So you have these little vertebrae here, here,
here, here, here. I’m just going to do this kind of quickly like this. Then you have the
vertebrae that go down. I know it’s kind of simplistic but we don’t need to do much
more than this. The vertebrae down here are much bigger, and it ends up being this arrow-like
thing. That is sacrum right at the bottom of your body. This is your posterior superior
iliac spine, or a good thing to remember are the dimples on your backside. They’re created
by bony protrusions on the pelvis. This is the ileum going away from us. You can see
the top edge, but then the edge disappears because it’s going forward. It’s like
the edge of my pinky finger. It goes like this, but you can see the top of my thumb.
Got it? So that’s what you see here. And because it’s a bony landmark I’m going
to hit this really hard to remind you of how important those are. They can be really important
in today’s lecture because they’re easy to find on anybody’s backside. Whether you’re
an adult, whether you’re male, female, a kid; those little dimples are really cute.
At the end of your sacrum you have your little tailbone right here. It’s also the beginning
of your gluteal cleft in between your little butt cheeks as they squeeze together right
here and your sacrum.
I want to put a little bit of the vertebrae in. It’s not going to be really clear or
something like an anatomy chart that you would see at a doctor’s office or anything like
that, but it gives you the idea of what we need. Then there are these little spinous
processes that stick out. I’m going to hit those in yellow because they’re obviously
important. I’m not even going to count even though I know that there are 12. One, two,
three. Oops. That doesn’t count as one. This one does. One, two, three, four, five,
six, seven, eight, nine, 10, 11, 12. I’m going to try to kind of make it a little bit
accurate. It doesn’t have to be. Each one of these vertebrae holds two ribs. Hence,
12 thoracic vertebrae create 24 ribs, which is your rib cage or your thorax, or as I call
it Thoracic Park. Okay, so this is the thoracic park area of your body. This is the pelvic
region of your body. In between these two areas between thoracic park and the pelvic
area is a bridge that goes from one to the other. That’s going to be an important part
of my lesson today. Down here you have—and I’m going to signify it by five lines: one,
two, three, four, five because there are five lumbar vertebrae down here. They’re bigger.
They’re weight bearing like this.
Now, one of the things you might be noticing that I’m missing are shoulder blades, scapulae.
Each one is a scapula. They’re roughly about ¾ height of the head. Then it changes angles
at about the same place that, if you could look through it, that the rib cage does right
there. So where the rib cage and that little corner intersect. This is just basically the
scapula at neutral, meaning it’s just relaxed because the scapula’s move around thoracic
park. I’m going to obviously blur this out. At this little corner you also have the spine
of the scapula. I’m going to just leave it like this for just a moment.
Okay, so the top part of the scapula is not going to be that important. On some individuals
I’ve actually seen that poke through around this area of their back. But for the most
part you’re not going to see much of that.
Let me just kind of fill in the—I want to remind you that all of this is actually bone
because I’m not going to go further down than this. I want to make sure that this is
looking pretty good. This is a hard area of bone. Then you have the thoracic park I already
talked about. I want to kind of clean this up a little bit for you. And the spine of
the scapula. I’m going to try to repeat that over here as well.
Something like that. I’m going to try to get them to be around the same area.
Then you have the spine of the scapula. And some
of the aspects that I think are important I will write down for you. Of course, the
superior aspect. This area here, I think, is pretty important. So what I’m going to
do is I’m just going to put like a little block here. It’s going to be simplified,
but really, this is what you need to know. This is called the acromion process. A process
is a bony protrusion. I know I’ve said that before, but I need to kind of keep repeating
that because it—you know, a lot of times this stuff sounds a little foreign. I want
it to become more and more familiar to you. It’s of the scapula. It’s specifically spine of scapula.
This is the acromion process of the scapula. This is the spine of the scapula,
and over here there is like a little bone that goes forward. It’s almost like my finger
is bent down like this, so this is a shelf, little shelf up there. That is what the clavicle
on the front side, your collarbones are attached to. I’m just going to draw these little
guys. You can see that they’re in front of or further away from us than the scapulas
and the rib cage. So the rib cage is over here. The clavicle, which I’m going to blur
out just a little bit. I just don’t want it to be too dominant. The part that you’ll
feel, though, is this bump. The clavicle is attached higher than the acromion process.
Do you see what I mean? Oftentimes, you’ll see a little bump.
Now, what I’m going to do is make this just a little bit more pronounced so you can see
it just a little bit better, but still, not as clear as other things that I’m drawing.
So I’m going to leave it like that. So those are the scapulae. You have the little plate here.
Okay, now the other part of the scapula, specifically the spine of the scapula that I think is important
to notes is that it has a little wave. It’s like this little wave of bone that if I could
put my finger underneath it would be like a wave going over my finger.
Okay, kind of like this.
If you ever look at the paintings of Caravaggio, and if you see a back view, sometimes you’ll
actually see him painting this. I’m going to hit these with a bright yellow because
I want them to be something that you remember as being important. Same thing with the acromion
process and the entire spine of the scapula. You can see that I’m giving this a lot more
importance. I want this to be clear to you as to how important it is. Also, these are
visible bones. Sometimes you see them as bones sticking out, and sometimes you see them as
actually like furrows, depending on what you’re doing with the arms.
I call this the first bone of the arm. It does kind of have a shape kind of like South
America like this. I don’t know if you can kind of see that. It’s the Pictionary version
of South America, like that. Over here by the socket or at least on this side is Columbia.
The bottom part is what they call the Tierra del Fuego of the scapula. Way down here. You’re
not going to find that in any anatomy book, by the way. You’ll find that in your geography
book. It’s an easy way to remember the shapes of things. If you liken them to something
else. It’s the way I taught myself a lot of stuff. It makes it a lot more fun, I think,
to learn. Now you can see a little bit of my little scapula and the entire framework
of the skeleton. That’s going to be important to us. The bottom part of the scapula that
I call the Tierra del Fuego or the inferior aspect of the scapula is actually pretty important.
There is also like a dish, an indented dish in here. That’s why I’m giving this a
little bit more umph like this. Same thing with this side. It’s like a dish. It’s
indented. This is where the socket is. It’s a very shallow socket where the humerus comes
out of. Then there is a tubercle and there is a secondary tubercle like this. And off
it goes on its merry way like this.
Since we’re not doing the arm muscles I’m going to leave this kind of a little bit unfinished
like this. This is the elbow. This is the humerus. This is the deltoid tuberosity, which
we’ll do when we do the shoulder muscles. Then this goes off. These two bones. Kind
of like that. Okay, so little by little we’re getting this a little bit clearer for all of us.
Okay, you like that? I hope so. Same thing over here. You have the ball of the humerus.
You have the tubercle. You have the tubercle. This is like that tubercle. These two little
bumps here, they create a little groove called the bicipital groove. There is a tendon that’s
going to run right through there right in between those two, and it’s for your bicep.
But right now I’m just going to kind of leave it like this.
It juts out almost like a kneecap, so I’m going to leave this one even less finished
because we don’t really need any more than this. Here is your elbow or the ulna.
Alright, good. So we’re on our way.
the sacrospinalis muscles. I’m going to write this down, and I’m going to give it
a nice bright, pretty—no, I’m going to use blue because they’re deep. I want them
to recede almost like mountains turning blue and purplish. Okay, so sacrospinalis.
Look at these words as I’m writing them, or this word but break it down. Sacro and spinalis.
In some books they call it the erector spinae muscles. I’m going to put it in parentheses
because I don’t want you getting confused if you have an anatomy book that says this
instead. It’s the same group. It’s actually a group of muscles, erector spinae. Or spine-a;
tomate-o, tomah-to. Usually in Latin ae would be just an e, saying it like ‘e’.
This is a group of muscles, so I’m going to write this down. Or a team. It’s like
saying the name of your favorite soccer team or football or baseball. It’s a bunch of
muscles. The reason I’m saying this, everybody, is because in most of your anatomy books is
you’re going to see variations on the sacrospinalis group of muscles. They’re the deepest muscles
that keep you upright like this like you’re standing at attention. They are extensors
of the back. So you have flexors in the front, erectus adominus, etc., that kind of ball
you up. And then you have the ones that straighten you up kind of like this. These are extensors.
You are extending your fingers. These are balling you up. These are flexors.
You have the same thing with your body so they do this. Bam, bam like this. Watch what
I’m going to do because I’m going to make this so simple anybody out there is going
to be able to learn and understand the deepest muscle because these deep muscles are really
complicated. There is like a whole network of muscles that go from the sacrum all the
way up the spine to the base of your skull.
So, who wants to know all of that? You don’t need to. I’m going to put just a little
bit more three dimensionality here so you can see that this like the whole head sitting in there
perched on top of this nice vertebra. So you have like this whole, big beautiful area up
here, and you have mastoid processes back here, etc. I’m going to even just give you—there
is like a big light source over here. We’re going to just make sure that you see the clarity
of all of this stuff. It’s important that you see almost like it’s a real person even
though it’s just 89-cent chalk.
So, the sacrospinalis group. Watch what I’m going to do because you are not going to not
be able to learn this. You’re going to learn this. The first thing I’m going to do is
I’m going to teach you about this form. And do you know what I call this?
That's right, a baguette. This is a baguette that you could get at your local deli. Grocery
stores usually have baguettes. I’m going to get just a couple baguettes here for dinner.
They go really good with spaghetti, etc., etc. They’re nice and round kind of like
this, right? They’re tubular. They’re delicious. I like to every once in awhile
when I’m teaching anatomy just take a break and talk about food. So I’m going to do
that for just a moment and just talk about baguettes. The other kind of bread I like
a lot—see if you don’t agree with me—is like the big ole’ French bread kind of like
this. They’re bigger. They’re fuller; nice and big and round. This is just like
a little commercial for bread. Okay, buy bread today. That’s it. That’s the sacrospinalis
muscles. That’s it. I’m done for the day.
Actually, let me just tell you what I mean by this. The sacrospinalis group is a bunch
of muscles including one of them called a multifidus. Instead of calling them all these
fancy words, I’m going to just talk to you about the two major forms that the sacrospinalis
muscles are and create on your back because that’s all you need to know, I promise you.
I’m not trying to shortchange you. It’s just I know all these muscles, and they could
drive you crazy. It would really actually turn you off to anatomy if I start getting
into every little aspect of the back. There are a bunch of muscles that I have to just
edit out because they’re not muscles that I readily see very often, if ever at all.
So what I’m going to do is I’m going to break down these muscles into two major groups:
the medial form and the lateral.
Remember, lateral just means further out from center. Okay, so this one
and this one. Okay, so the one thing I can tell you really easy right now is that these
two fit right in between these two landmarks, the posterior superior iliac spine, P.S.I.S.
Like that. There is the ileum and the vertebrae. These two would fit right in here so let’s
draw them. It’s almost like there is a form. It’s very tight, very deep and buried underneath
everything. Right now I think I might just show one side because I might put some of
the deep muscles here and some of the superficial muscles there. Or maybe not. Maybe I will
put the other one on and then just deal with the other forms later. One of the things that
you’re going to notice, though, is that I’m going to blur this out. These do go
all the way up. There is a bunch of muscles that kind of do this to various degrees they
open up allowing for the spinous processes to show. This can be highly individualized.
Some people have—it’s called what I call the pea pod. Some people have what appears
to have what appears to be a pea pod on their back. Okay, can you kind of picture that?
Maybe even your own back. That’s what this is. The sacrospinalis muscles especially the
multifidus muscles, which are these; they’re very tight. They run along very close to the
vertebrae all the way up like this.
The reasoning I’m softening out my marks is because down here they’re very clear
and very tubular like this. I’m just going to put like some form lines. I want to put
a bunch of form lines like this just on one side for right now because I’m going to
put a lot of muscles on top of that. You can even see them coming down into the sacrum
until you have the crease of the butt right in here, the gluteal cleft.
Okay, so these are very strong muscles. They’re thin but they’re very strong. When they
contract you get pulled at attention. The other good thing about those too is this:
When you look at the side view—excuse my back for just a second—when you see the
side view of a person like this one of the things you’ll notice is that the rib cage
has kind of a like a slant to it like this.
The vertebrae has that recognizable S-shape that makes us look so
nice and beautiful and elegant and allows us to walk upright without feeling too tired
in doing so. Here is the pelvic area, great trochanter of the femur, etc. There is the
femur itself. The lower part of the lumbar part of the vertebrae becomes the sacrum right
in here. It has a counter angle. So you have an angle like this, an angle like this, an
angle like that, and an angle like this. Just like that. Then the ribs tend to fall in this
direction. Without the arms it’s really easy to kind of show this like this. Until
you get to the cartilage then the ribs kind of do this like that. Alright, so you have
this kind of a look. Now, the reason I’m doing this is because when you look and think
about your model—oh, one of the other things I want to draw is a scapula because it actually
has depth. It creates a contour change on your back like that. So far, so good?
The sacrospinalis tends to straighten you out right here like that. Got it? Now, the
other thing I’m going to draw really softly for you are the abdominal muscles like this,
just so you can kind of start getting a notion as to what’s happening with all of this
over here. And the sacrospinalis muscle, the multifidus right in here specifically kind
of straightens that out. Then there are your butt muscles going like that. So they’re
very tubular and they’re very strong like that. So all of a sudden you’ll see that
it changed the direction of your vertebrae or seemingly it changes the look of your back,
your lower back. So that’s the medial form. Now I’m going to put—okay, so I’m going
to put the French roll because I want you to remember this.
Big old French roll and then the baguette.
Here are the vertebrae, as you can see. Sometimes you can see the vertebrae all the way down
somebody’s back. You can see what appears to be like a row of beads, something like
that, like just beads all the way down and all the way up. Sometimes you see a pea pod
down here. Sometimes you see it up there, sometimes in two spots. Just take a look.
Some not at all. You see a crease all the way down somebody’s back. It’s all good.
It’s all different variations on a theme. Now I’m going to put the lateral form. And
lateral means further out like this. So one kind of like overlaps over the other, and
it kind of like makes this meandering big kind of a shape like this. You can still see
the multifidus underneath. I’m still trying to make sure that you don’t lose that. So
you have two forms, one on top of the other. It’s like a transparency of forms.
It's a really interesting thing.
You don’t need to know this, but there are all these like little attachments to ribs
that these muscles have. They’re almost like a rock climber just grabbing onto stuff.
I’m going to teach you something that is fabulous that you do need to know. See this
border? It kind of meanders about. It depends on the person. Sometimes it’s fairly straight.
Sometimes because there are multiple forms to that muscle there is a little indentation.
You can see this on a person’s back. If you have a model that raises his or her arms,
oftentimes you’ll see what I’m talking about. This does go all the way up.
I’m going to keep blurring this just to remind you that it does go all the way up
the spine. But, where I’m blurring it out, it’s blurred out because I’m going to
put so many thick muscles on top of this that you’re going to see this. It’s almost
like they go through a tunnel, and that tunnel starts at the Tierra del Fuego, from this
point to that point. They go underneath a whole bunch of muscles. That’s why oftentimes
these are going to be most visible very low on the back. A lot of times when a person
bends backwards they’re going to crease right here; right at the bulbous of the sacrospinalis.
Do you remember how I called this thoracic park and this was the pelvic area? So this
is hard, this is hard. It’s like a land mass, a land mass, and this is a bridge.
So if you have a whole bunch of people going over from land mass to the other, and there
is only a narrow bridge, what they do is they have to go tightly across that bridge. Then
when they get to the big land mass across the way then they billow out, and they go
their own way. That’s exactly what’s going on.
Over here at thoracic park these forms get bigger.
so that you have a rib cage that does this like this, and you can see that I’m rotating
this body like this, like this, like this. One of the things you’re going to see is
this. Here’s the scapula and then here’s the scapula over here. Okay? Can you see all
this? Here is the rib cage. The vertebrae bends like this. Does this, C7. See what I
just did. Now, what you’re going to see is the sacrospinalis. Why, because it’s
right in between the two little points, the posterior superior iliac spine. Here is the
vertebrae and, sure enough, here are these posts nice and tubular like this.
Then guess what happens? This billows out like that to the point where a lot of times
this is the contour of the body. So when I put the external oblique, the external oblique
would be like this and like this. Do you see that? You’re going to see this a lot with
classic drawings. You’ll see this. Maybe a person’s arm is going back like this,
like this. And then this is the way the body is. What pokes out is the sacrospinalis because
it’s big and billowy. Okay, so here is one form.
Here is the other form on the other side.
Remember that because that’s the new contour. It’s not this because from over here this
is a raised portion. So it’s almost like here is my finger and here are my fingers
here. So if you’re far enough this way you won’t be able to see the finger because
it’s the outside edge. I’m going to make sure that you can see these ribs because what
happens is these ribs tend to disappear when they hit the sacrospinalis. This is very common.
You’re going to see this often. All of a sudden you won’t see ribs anymore. They
disappear because this is so thick.
So when you look at the drawings by Michelangelo you’ll always notice that he never makes
the mistake of drawing the ribs all the way to the center because he knows that the sacrospinalis
muscles are so thick that they tend to disappear underneath there. Now, I’ve seen some models
that are so thin that you can actually still see this a little bit, but that’s not very
common. More often than not the ribs tend to disappear right
when they hit the sacrospinalis muscles.
Now the next muscles I want to put down are also very deep, and they’re attached to
the center right here, this line of the scapula like this. They’re called the rhomboids.
Let me write that down. Usually we just call them rhomboids, plural, because there is a
major and a minor. Okay, so rhomboids major are down here and they’re big, and rhomboid
minor is up a little higher. Rhomboids. And rhomboid, just to remind you of school, is
a shape that looks like this. That’s a rhombus. A rhombus is like this like this shape right
in here. It has two acute corners and two obtuse corners right here like a diamond.
So that’s how this one got its name. It’s roughly attached like where the C7 is. And
the muscle fibers do this, and they do, in fact go over the sacrospinalis.
Remember what I said about me editing? All of us anatomists, me included, have to edit
our muscle selection that we give to our students because it’s just ridiculous to go over
every single muscle. This time I’m going to leave it a little bit more blank because
I need to put more muscles. This one I’m going to leave alone. It’s attached to the
vertebrae here and to the scapula right in here. Okay. So far, so good. You’ll see
that, just to remind you, it would actually create like a little shadow over the sacrospinalis
right in here. Just so you can just remember.
There are fibers that really pull like this.
What they do is they bring your scapulas together. If you were to activate this muscle it would
shorten, and it would bring this scapula closer to center. Do you see what I mean?
Now that you know that, I’m going to put a muscle in there that does the opposite.
That is to move the scapulas away. The color I’m going to use with that is, again, blue.
And underneath the scapula where I’m putting these little dots is the serratus anterior.
Remember, I talked about that when we were doing the front torso. The muscle drapes,
and it goes forward because it originates on the front. It depends on how big the person is.
You know, big meaning like muscles. Big muscles will create like a big bulbous mass here.
This drapery is very apparent on all of us. If somebody reaches back to stratch
their back or something sometimes you’ll see this real deep, almost drapery effect.
There. So it drapes from this point right down here.
But remember, it’s underneath the scapula.
If you remember from the front torso here is the, let’s say the nipple is right in
here. So this is where the serratus anterior, which is the muscle I just put on there like
this. And it’s underneath the pectoral muscles. So what I’m going to do is I’m just going
to kind of leave it like this like that. Serratus anterior. Okay, pectoralis major kind of does
this, covers this whole area up. All of this is serratus anterior like that. This scapula
would actually show a little bit more of itself. It would be like this. The spine of the scapula
would be like this. I could put an arm going forward like that. Just going to make it a
little bit clearer. I’m going to make sure that the bottom part of the scapula has muscle
on it because that is the serratus anterior. The serratus anterior, sure enough, serrates
in here like that like a serrated knife.
As you know, the external oblique will enter mesh with that so I’m going to leave it
like that. Okay, so we’re moving along. So the serratus anterior. Now where am I going
to put that. Let’s put it over here.
Anterior reminds you that it starts in the front. Serratus anterior. Fabulous muscle.
So that I’m going to put on the other side just like the belly of it, just like the form
that it will create when we put the other muscles over it. Okay, so you have to remember
that this is a form, and you can see it changes the form of that rib cage now and forever
like that. I’m going to make it a little bit fuller. There it is. Now I need to and
I want to put the latissimus dorsi in. I’m trying to see which pretty color I want to use.
I’m going to use this one.
Latissimus dorsi. That one is shaped kind of like this:
First of all, let me tell you where I’m going to start it. I’m going to start it
where that X is. I’m going to end it where this X is on the ileum. See that? It also
has an aponeurosis will take it to the center of the body at the vertebrae. The latissimus
dorsi—let me see. I’m going to just get rid of a little something here so I can have
a little bit of room to draw this because I want to draw it off the body, off the body first.
Okay, so see that X? That would be over here. There is another X but it’s over here. I
need to make sure that you guys are paying attention to this. How am I going to do this?
Oh, I know. I’m not going to use an X. I’m going to use little dotted lines. See those?
That means that’s in front of the bone. The bone is going to be here, and that is
in the front. So I’m going to just make it blue just to signify that it’s actually
in the front of the arm. Okay, so that is going to be here like this. Then the other
X, of course, you can see down here, is this guy right here, roughly. So now what you end
up with is you have a muscle that is very sheet-like. Okay, it’s very sheet-like and
it does this. I’m going to draw the thickness of it because it has thickness. In the photographic
reference that I’m going to show you shortly you will see it on one of our fabulous female
models. This is because it’s got a little strap. See what it does it is does this, and
it comes back around like this. That’s what I’m trying to depict. This is going around
the serratus anterior. Then it’s got a couple little attachments like this when there are
ribs. Then there is no more rib so it comes down to the ileum which is this right over
here. Then it’s attached to the center of the body by an aponeurosis. Let me write that.
Lumbar, because that’s the lower back, aponeurosis, which sounds like you’re sick or something.
You’d better see a doctor about that lumbar aponeurosis. But all that means is aponeurosis
is a sheet of tendon. It’s what attaches this muscle to the center of your body or
vertebrae like that. So it’s a sheet of tendon. Remember that. Kind of like the one
I talked about with the front torso, the one that covers abdominal muscle. That’s a lumbar
aponeurosis. When I put that over here, watch. It clips Tierra del Fuego, does that, does
that, goes around this. It’s attached to a few little ribs, and then all of a sudden
it is all the way down here. Of course, because it’s a thin muscle you can still see all
the forms underneath it. So I’m going to leave it almost ghost-like, and including
you could still see ribs because it’s a sheet of tendon. It’s a sheet of muscle.
Then the aponeurosis will finish this off.
I’m going to try to show that to you. This is muscle. Muscle. Muscle. You can see where
it’s attached on the front. I’m going to make it a little ghost-like. This is closer
to us. Do you see that? This is the thickness of that muscle like this. So you can actually
see this thickness on certain individuals. Isn’t that amazing? Again, you can see the
shading that is underneath it from the serratus anterior. You can see the ribs and you can
see the sacrospinalis and multifidus and all of these beautiful muscles underneath it.
It’s important that we remember all that, that we didn’t lose any of this. But it’s
a complicated little area. That’s why I drew it right there. The muscle fibers do
this. They spray out like this and they find their way down to almost the ileum. I’ve
seen this on cadavers many times. Sometimes the muscle fibers reach all the way down.
Sometimes they don’t. It doesn’t matter because all of that is attached to the center
right in here.
Now, one of the muscles I want to put in is that external oblique.
Remember this guy? Your love handle muscles.
Sometimes in workout areas it’s called just obliques,
and that is here, and it’s inter, kind of, connected.
That is that muscle. So this is the one that we’ve already done
from last week. I’m just going to fuzz that out because it’s less important this week
than the latissimus dorsi. But it gives you a sense of like the finished product, you
know, the body in all its glory. It ends up being like that. Pretty neat, eh?
imply that there are in fact neck muscles including the levator scapulae, which basically
kind of does this. It sprays out. Scalene muscles. There are all these—but what I’m
going to do just quite simply is just do that and do that just to remind you that there
are muscles underneath the trapezius so when I put the trapezius in it won’t look so
silly and alone. This is the levator scapulae.
Keep this clean.
It’s a neat muscle because you can actually see it sometimes.
Okay, so the trapezius. I’m going to use red. I’m
going to use this pink just to differentiate it from the muscles I just did. It’s attached
to the vertebrae by a tendon, but it goes around C7. It goes down, down, down, down,
and passes, and it goes over the latissimus dorsi. It’s attached somewhere along the
thoracic park region.
Now, the region I say somewhere is because that is highly variable. Don’t let anybody
tell you that it goes down to T12 because sometimes it does. Most often it does not.
I’ve never seen it really go down that far. If I have it’s pretty rare. So how far down?
It just depends on that individual. I have one model whose tip of his trapezius is actually
about the same level as the bottom parts of the scapula. So it’s a variable muscle.
The bottom part of it, though, is tendinous. All of this is tendinous right along here.
All along here. But you can still obviously see the spinous processes, but there is a
tendon all the way down. Then there is a triangular tendon down here. I’m going to tell you
why that’s important to know.
Okay, so over here we’re going to put the muscle. It’s attached to the front of the
body on the clavicle. The reason I’m putting that in is because I’m going to put the
line where it’s actually going to fall because it’s going to disappear. It’s going to
get covered up. All along here. Then the muscle fibers do this. They do this and there is
a tendon attached here to that little area right in here. Oftentimes Michelangelo will
draw the back, and he’ll make it look like there are big dips in here like a hole. The
muscle fibers do this. They do this. They do this. They kind of spray out, and they
start coming down like this at an angle down to this tendon down here. They go to the front
so what you’re going to see now is just this, this, this. Every once in a while you’ll
notice that the trapezius looks a little bit more complicated than something like this,
and the reason is that in about this little area right here the muscle fibers are in the
same line of that corner and C7. And because of that it oftentimes creates the illusion
that there is a muscle up here, and then there is one down here that is shaped kind of like this.
Do you see that? There is the top superior form
and the inferior form
leaving this nice little triangle here called the triangle of auscultation. So that little
guy right there—hmm, where am I going to put this? Triangle of auscultation.
To auscultate means to listen, so the reason that has that name is because way back when,
even in the time of Galen, which he lived—oh, I’m trying to think—about 130 A.D.
He knew if he put his ear in that little whole, and if he had somebody move their shoulders
forward that opening opens up, and it gets your ear closer to listening to somebody’s
insides so it would give them a pretty good idea as to what was going on inside the body.
To this day that’s where the stethoscope can be placed is in that little triangle of
auscultation. The neat thing about that is is when I show you the photographic reference
you’re going to see it very clearly. That always identifies three major landmarks: the
scapula, the latissimus dorsi, and the trapezius, so it’s fabulous. It’s a really neat little
landmark. I just wanted to give you that. No extra charge. It’s wonderful to know
that, and it’s important that you know that because you can see that very easily on the model.
Now the trapezius, as you may expect, can vary greatly. It can be a nice swoop like
a circus tent, or it can be big and bulbous. Remember that this is like a superior form
of that muscle. It’s not a different muscle. It’s just an aspect of it that makes it
a little easier right in here. Okay, so hopefully all of this is clear to you and the back won’t
be such a dark mystery. At least that’s my hope. It can be very intimidating. Once
you know the back it’s amazing how liberating it feels to know it and to be able to depict
it and to understand what’s back there. Just remember that. Don’t let like the movement
of the body throw you. It can be a little confusing, but by going over your notes of
what I’ve been teaching you, it’s amazing how much clearer all this stuff is going to
be. It will make a difference when you do your artwork and when you look at the models
from now on. It really will. It will make a huge difference. I’m just going to try
to give this a little bit more dimension so you can see all the ins and outs. This casts
a shadow over here, and this is the socket. It’s a very shallow socket, so it’s actually
called a fossa, the glenoid fossa. I’m going to look at it just a little bit just to make
sure that what we have here is going to be really good and clear. I’m trying to just
clear up a few little forms for you. The muscle fibers kind of do this. This opens up right
in here like this, and it comes down the center.
I’m going to put the latissimus dorsi on this particular figure just really quickly
like this. Watch. It just goes… See where the bottom part of the scapula is? That’s
all you need to remember. Like this. Another side like this. Like this. It meets up with
it. You don’t see it too much, but there it is right there. You put the trapezius in.
Now it’s actually pretty easy because this is all the trapezius does. It just follows
that same pattern no matter what. The other thing to remember to look for on the back
is what my teacher Burne Hogarth used to call the M of the back. And the M of the back,
scapula and the trapezius and the other scapula. That’s the M.
Okay, so remember the M of the back.
Right in here, everybody, just to remind you, M.
Okay, I think that’s it, everybody. I’m glad that I got to teach you a little something.
Here is the latissimus dorsi covering up the little fingers and voila.
The one on the left is a female. The one on the right is male, if you’re not sure. Also,
because we wanted to show a little bit of a dynamic pose rather than just a static back
view. The one thing that I want to remind you of that is always like something you look
for is where the scapulae are. One of the ways that you could look is—basically if
you find one aspect of the scapula then you could more easily find where the other aspects
might be. So right now this area here is the acromion process. I know that simply because
the deltoid or the shoulder muscle surrounds this area. I haven’t talked about this muscle
too often yet, but it does. It’s your shoulder muscle. The trapezius goes right into it.
So this little red dot that I put on there is your acromion process because that’s
where all the bunching up happens on your shoulder. Now that I know where that is I
look for this spot right here because this is where—so basically what I have is this.
I have one spot here and another spot here. Got it? Down here I see another spot. So that’s
it. That is the scapula. The spine of the scapula. Medial line of the scapula. Perfect.
Because once I know where that is then you look for the sacral triangle which would be—in
this case it’s going to be like this. Okay, because on her, her latissimus dorsi not only
clipped the Tierra del Fuego of the scapula, it actually rode above it.
So this is the triangle of auscultation. What’s neat about that is that will give away the
position of three things, and I already told you that. The trapezius, which you see very
clearly right there; the scapula, which you can see here; and the latissimus dorsi, which
on this young lady you can see very clearly going up. It’s fabulous.
The other thing you’re going to see is this bubble. That bubble is the serratus anterior.
So the serratus anterior is creating this. Okay, the other thing you’re going to see
are her dimples. These are the posterior superior iliac spines. The rhombus of Michaelis is
in here. But in between this dot here is the vertebrae as it goes into the sacrum or the
baguette. Then this shadow will signify the French roll. So those are the sacrospinalis
muscles. On the other side you can see the mirror image of the trapezius, but because
this arm is really stretched and her body is stretched over here, on this side it’s
compressed, then what you’re going to see is a stretching of everything.
So now over here you have this area where the scapula really, really gets forced like
this. You may not be able to see it, but the latissimus dorsi follows in this path right
here. The trapezius goes around this little area of the scapula. That’s how I knew where
the scapula was, by the way. This gave it away. That little dip. These are the muscle
fibers of the trapezius. That’s about the extent of it. This is where the trapezius
goes around C7. You can see the superior aspect of the trapezius doing that. The muscle fibers
kind of continue doing this, this, this, and then they start going down this way like this.
You can see just a little bit of the tendinous separation here, but because she’s very
lean her trapezius looks more like it comes down to a point. As opposed to when we jump
over to the male, his trapezius looks more rounded at the bottom. The tendon is really
thin but the muscle is big. You can see the pea pod right in here.
So in this case, once again that’s the acromion process down to this spot and to this spot
which is hiding from us. So the scapula in this case is there. That is one part that
we know. This is the other part that we know. Then there is the scapula on this side like
this. Once you see those then you have everything pretty much taken care of because the trapezius
lays on that. Here is the superior aspect. Here is the tendinous region that goes around
C7. Then it comes down and it looks for, and you can see, boy, he’s really, you can see
he’s very lean. That’s the trapezius. You can see the latissimus dorsi and the triangle
of auscultation. You can see ribs but you can’t see them beyond this point because
this is the sacrospinalis. All of this.
Over here it kinks up and he has subcutaneous fat. When he leans back and he straightens
up you’ll see kind of like a little kink areas. The posterior superior iliac spine
is here, and there it is there. So you can see that the baguette portion of the sacrospinalis
is there, and then the French roll part is there. You can see poles from the external
oblique, latissimus dorsi, and underneath the shadow is the serratus anterior. I see
a little bit of light and a little bit of the latissimus dorsi here, trapezius there,
and the triangle of auscultation is almost closed up on this side. You can see the muscle
fibers. That’s it. That’s it, kids. It’s as simple as that. There are two tubular forms
that kind of mimic the two tubular forms down here at the base of the back and at the top
of the back. You kind of have almost like a mimicking of those muscles. Over here the
trapezius bounces because the arms are up, and the same thing here. Okay, that’s it.
Now, I’m going to draw the muscles for you.
since the left side is in deep shadow. It’s okay to just kind of do one side. What I’m
going to do is draw some of the muscle forms and see if we can make all of this clearer
for you. The acromion process, as I said, is buried inside here where the deltoid is.
The muscle fibers go kind of like this. I’m going to look for C7 because C7 is always
like a little landmark, so it’s roughly there.
The reason I’m saying that is because I’m also looking to see where this corner is right
in here, where the scapula is. The spine of the scapula starts and ends at the acromion
process because the muscle fibers actually do this. If you look very carefully on her
skin you can actually see that. Now, there are going to be a few discrepancies here that
you’re not going to see very easily unless I explain them to you. You see poles over
here at the center, and that’s actually because of her vertebrae. But the muscle fibers
are, in fact, going in the direction that I’m drawing them. This is here trapezius.
I’m drawing this first because it’s on top. When I work on the blackboard I start
with the deeper muscles because that’s the way it’s done there, but when I’m doing
a drawing like this I have to start with the top layer first and get to the lower layers afterward.
So this is the direction of the muscle fibers, and then when it gets to about where the spine
of the scapula turns and goes towards the acromion process then this is what kind of happens.
The muscle fibers do this and they’re twisting towards the front of the body. I’m
also having them roll because they roll towards and land on the spine of the scapula, so I’m
trying to make that clearer to you. The spine of the scapula is here. I’m going to draw
that a little bit more clearly than you are able to see. This goes forward. This is the
scapula underneath all this. You can see the shadow here. Now, when we get to the shoulder
muscles, I’ll talk about those lumps and bumps. Over here, this is where the humerus
is in this area, right in here. Okay, but now it’s like these muscles. Trapezius.
They go around C7 like so. Because of that they can actually show themselves often and see if this makes sense. It should start
looking some of your anatomy books. Albeit we’re doing it much more quickly than if
we had the luxury of hours and hours of being able to do this. The muscle fibers end and
then this little area here is tendinous. This is the tubercle of the spine of the scapula.
I’m going to draw the whole scapula or the whole spine of the scapula right in here.
You can see that the muscle fibers are attached to it.
Remember that the trapezius is also attached on the front on the clavicle at the distal
end, the further away end. The part that’s attached to the acromion process, about a
quarter of the way in. You’ll find that different books tell you different things.
I just find it to be just a little bit of a quarter, not quite a third. On the other
side you can really see the trapezius. I’m going to just outline it like this including
the tendon so you can see how it goes around C7, the superior aspect of it goes like that
because it creates that bubble. Okay, it’s going to clear. Then this is the border right
here. This is the edge of that trapezius.
One of the things that you’re going to see very clearly on this young lady is—it’s
amazing how clear it is. This is her latissimus dorsi. This eclipse covers the bottom part
of the scapula or the Tierra del Fuego as I call it. You can see the muscle fibers would
do this. But because they are on top of covering the serratus anterior, you can see that there
is a shadow that is created here. I’m going to make that clearer for you and really shade
that in. This disappears because it’s attached to the front of the humerus.
It goes like this.
Now, I’m going to locate her pelvis, and the easiest thing I could do right now is
to locate her pelvis by locating her dimples. That’s the posterior superior iliac spine.
And her ileum does this, and you can see it’s kind of poking that out just a little bit,
so this is where that would be. The reason is because you can see her latissimus dorsi
doing this. It goes in and it disappears. You’re not going to see this part that I’m
drawing. You’re not going to see it on any living person. I see it on cadavers all the
time, but you’re not going to see it on this young lady. You can see some of the effects
of subcutaneous fat. Subcutaneous fat is great because every, you know,
person that is healthy will have it.
Now, you’ll see that all of this stops right in here. This lighted area is her sacrospinalis
muscle. The direction of the muscle fibers of the latissimus dorsi spray out from the
arm, and they go like this until they become parallel with a side edge of it. Sometimes
one of the things that you’re going to notice is because these are attached to ribs right
here, sometimes you’ll actually see a piping along the lateral border of the latissimus
dorsi. I’m going to put a line there just to remind you that you might see that on a
person. One of the things that I’m going to do really quickly over here is remind you
of something that is kind of neat, and that is these two little people. I’ll get back
to my little drawing in just a moment. But on one side you have a vertebrae that doesn’t
really quite make it all the way down, and here’s like the little butt cheek, the gluteal
cleft like this. Then there is what seems to be a little rhombus here. That’s the
rhombus of Michaelis. That is female. Sacral triangle is male. So on this side what I’m going
to do is I’m going to come all the way down and just draw a little triangle like this.
And then here is the ileum. Here is the ileum. Little tiny drawings like this.
Now, the great trochanters on a female are a little further apart. On a male they’re
less. They’re like here. You can already see the difference between the two. Females,
now this is a very lean female that we’re drawing over, but there is a fat pad that
makes her look more girly, and it fills in this little area here. Female shoulders are
generally narrower so that the rib cage kind of pops out. On men they’re wider so you
tend to be more triangular as you see on our male model over here.
Okay, so all of a sudden it’s like, yep, that’s the difference. That’s the major
difference. The flank muscle is more apparent on males because you don’t have that girly
fat pad. So all of a sudden it’s like, yep, that’s one of the major differences with
males and females. Here is the base of the skull, base of the skull, and female, male.
Now, continuing this drawing, remember that this section can appear to look like there
is piping there, and now you know why. The muscle fibers do this, and they end where
my pen is ending right in here, but this end, these ends are attached to the center of this
vertebrae right in here by an aponeurosis. So I’m going to leave it blank. That’s
why you can see inside this aponeurosis. I’m going to draw very, very lightly. You can
see the multifidus way deep inside the back. Then this is the muscle fibers ending like
this. How do you like that?
I think what takes the longest time is just to do a whole bunch of these like little fibrous
lines. It’s like drawing hair. You can see the forms underneath. Ribs like this. I’m
going to show off a little bit more of them and a little bit more of the shadow of the
serratus anterior. And sometimes even some of the deep forms. Inside the triangle of
auscultation you do have your rhomboids, and they go off in this direction like this. Sometimes
they’re visible up here. Sometimes the rhombus can actually pop through the trapezius in this area.
Over here the muscle fibers start becoming a little bit more horizontal, but then they
start moving down like this and radiate out from this little spot right there where the
spine of the scapula starts going toward the acromion process. This can be deep, as you’ll
see on the male model.
Over here is her very delicate little external oblique way down here. Latissimus dorsi right
in here. I just want to give it a little bit more ummph before I go to the male. Remember,
these little muscle fibers where they end, they’re attached to the center of the body
at the vertebrae by way of the lumbar aponeurosis all the way down here.
of the trapezius very apparent. It’s also very apparent that they go around this tendon.
You can also kind of sense a little bit of the pull of the rhomboids. This is where the
turn of that scapula is going to be like this, and then this swings away from us. You can
see the latissimus dorsi right here and underneath it, that’s right, the serratus anterior.
This line right in here you can see before I darken it up. It’s the trapezius. You
can also see that I’m going to just start radiating from this point like this. Like
this, like this until it becomes parallel with the contours of it. Over here because
he is a guy and he’s really well built that the separation between the muscle and the
tendon becomes very apparent. The tendon is this little triangle that I’m drawing, and
it goes around his spinous processes or the pea pod that I told you about. The sacrospinalis
is very apparent all the way up this line right here. That light, light line. You can
see that. That’s why you can’t see ribs until you get past that. This is the trapezius.
Another side you can see it like this. I’m just going to diagram it. All this area here
is the trapezius. It goes like this. It’s attached all along here. All of this is trapezius.
Deltoid is going around it. That’s the acromion process right here. This is the trapezius
on this side. It goes around C7 like this. This is where C7 would be. Over here you can
see the muscle fibers going around. On this side I want to just keep it a little bit more
like a simple diagram. You can see that it opens up here, and the muscle fibers do that.
We can see them pulling. Latissimus dorsi on this side is here. Over here it’s going
to be lower, and the scapula is over here. This area right in there. I’m going to make
this really dark because I want you to see it like that. This is tendon right in here
where these muscle fibers are attached. The latissimus dorsi on this side is over here,
so the triangle of auscultation is in this little area right there. That’s the little
triangle. It’s like a Dorito.
Over here you can see it very clearly. This is like the edge of the scapula with muscles
that I will talk about later. Infraspinatus, teres major, etc. The shoulder muscles. Right
over here as I did with the young lady, I need to do the muscle fibers. They radiate
from that point. They’re bouncing around. I mean he’s pretty fit. You also have to
remember that there is a lot of subcutaneous stuff. The skin is very thick and fatty.
Maybe that’s the way I should say it, actually.
There is a good layer of fat underneath the skin or attached to the skin or part of the
skin. Subcutaneous fat is a wonderful part of the human figure. It makes us look healthy.
It provides stored energy. We’re not very efficient. We’re mammals. We’re not reptiles.
Reptiles are a lot more efficient because they don’t have to regulate their temperature.
They just kind of sit on a hot rock when they’re cold and hide and seek shelter or someplace
cool when it’s hot. We tend to keep the same temperature all the time, 98.6 F, so
what happens is that our bodies are constantly working hard. We’re always like running
idle, so we’re always burning energy or gas or however you want to look at it. Whereas
reptiles don’t, so they don’t need to eat as much. We need to eat every single day;
otherwise, we start getting hunger pains. Reptiles don’t. Big difference. So we need
that subcutaneous fat for stored energy that reptiles really don’t need. That’s why
you don’t see too many chubby lizards. I guess you can. Some lizards I’ve seen get
kind of—it’s usually in terrariums. There.
What I’m going to do is give you that border. Now the muscle fibers of the latissimus dorsi
do this, and they start becoming more and more vertical. Now you can see all sorts of
poles because there is like serratus, posterior, inferior. There are all sorts of like funky
things that happens sometimes, so you have these real funky forms that a lot of times
are kind of hard to figure out. But you can see ribs here. Part of this little dip to
my eye is the external oblique. It’s what I see.
I have to find where the posterior superior
iliac spine and visualize where the pelvis is. So to me it’s here. On the other side
it’s a little easier because there is a lot of shading that kind of give away certain
information. This is the outline of the latissimus dorsi. Anything to the left of this line that
I’m doing right now is going to be an aponeurosis like I drew on the young lady. Like the young
lady I’m going to draw little hash lines here to remind you that there is a shadow
that is created by the multifidus or one of the sacrospinalis forms, the medial form.
Over here is the lateral form or the French bread. So what I’m going to do is get this
to spray out like this, fan out like this, like this, until it starts becoming parallel
with the lateral edge of that latissimus dorsi. Over here there are a couple attachment points,
two ribs. But then there are no more ribs, and there is that. Then there is the external
oblique intermeshed with that. All of a sudden you’ll see this kind of a meshing aspect.
I’m going to try to intermesh some of these forms. Then this goes all the way down there.
I’m going to do that a little bit better with her too just cause it’s pretty. Sometimes,
you know, that’s all it takes is something looking pretty. We’re doing everything at
our disposal for your education. I work really hard to try to make things clear to you. This
information is just so difficult for me to understand for such a long time, and I didn’t
always have anybody to go to. So I read a lot and fortunately at Art Center College
of Design with Burne Hogarth, he was like the main instigator to get me going on anatomy.
It’s been an honor to teach in his room for so many years. I teach my class very differently
than his, but anatomy is anatomy. Same information. Different approach, different delivery. A
very different style than he had. It’s not good or bad. It’s just I’m a different
person than he was.
Okay, so here we go. Remember this whole section right in here is the aponeurosis, the lumbar
aponeurosis. You can see the beginning or the creation right in here of the triangle
of auscultation with the rhomboids inside. The rhomboids are doing this. They’re going
in this direction. Underneath all of this.
Alright, so here is the latissimus dorsi. It’s beautiful
and it’s a sheet. When I do the ecorche portion of this you’ll see what I mean because
this looks like, it’s going to look like a wet Dorito.
When we draw over these beautiful models it will resonate. It will actually make sense.
All of this is the beauty of anatomical knowledge, and it’s becoming more and more apparent
that we need this still. It’s not just for the old masters. It’s for the new masters.
All of you.
You can see that the border here is really pronounced on him, on this male model, so
it creates a really deep well here. There is an aponeurosis that surrounds this area.
It covers up like from one side to the other right in here. It creates almost like a little
diamond shape kind of like this around C7. There is a ligament down the middle of the
nuchal ligament. If you finger in this little section right in here and bend your head down
toward your belly button, you’ll actually feel it hitting your finger. I’m going to
write that down for you. I’m going to make sure that you can see the superior border
of the latissimus dorsi and the fact that it has thickness to it. I don’t want you
to forget that there is a muscle underneath it, and that is the serratus anterior. Remember,
it’s clipping and it’s covering part of the scapula.
Do a few more strokes for you. Reminding you that you can see ribs underneath. You can
see all the forms including the sacrospinalis. I’m going to try to get the sacrospinalis
to kind of pop out here. See that? Isn’t that neat? Did that just for you. Make sure
we could see the sacrospinalis right underneath there. The sacrospinalis is all of this right
over here, and there is the multifidus part down to the sacral triangle. And on here it’s
rhombus of Michaelis right in here. She’s especially lean so you’re not going to see it quite as clearly
as her, but you can see that on our male model how far down the multifidus comes down.
I told you that was going to be doable. A lot of times when I mention the back or triceps,
things like that, it scares people because the back muscles are complicated. But now
you know you don’t need to fear them. Okay, so we’ll see you next time.