Hey, I'm Stan Prokopenko.
Welcome to Proko.
This lesson stars one of the coolest
and most powerful areas of the human body.
The front of the leg.
It has some of the biggest muscles we've got,
going by sheer weight and size.
So dynamic! So powerful!
So confusing!
The asymmetry can throw off a rookie,
but don't worry,
this lesson will teach you what you need to know.
Let's introduce the four muscles.
The quadriceps femoris is a four-headed muscle
Each head has its own name,
So let's say hello real quick.
Vastus lateralis is the largest of the bunch,
On the lateral side.
Vastus medialis is this big meaty teardrop
On the medial side.
Vastus intermedius on the interior,
It's a deep muscle we don't need to worry about.
And the rectus femoris in the middle.
High up in the middle.
They all originate on the femur
Except the rectus femoris,
Which originates higher up on the pelvis.
But not all the way up where the sartorius and TFL attach,
Just a tad lower, right here.
We group all the quads together because they
share the same quad tendon,
After insertion to the kneecap
Which attaches to this ligament,
Which then attaches to the tibia.
Remember from the premium knee episode
that the purpose of the patella is to help the quads
To straighten the leg.
Wooooh, wow!
Yes!
There you go, you just learned the origin, insertion and
Action of four muscles.
That's twelve things already.
Patterns like this make the quads a little easier to learn.
But it's the shape
And forms of these muscles we're concerned with,
And that's the hard part.
The quads can look really awesome
When drawn well.
So let's learn how to do that.
Asymmetry
From the front, you'll want to look for asymmetry.
The sartorius and tensor fasciae latae
Create that 'V' shape that leads nicely into the gesture
and large teardrop shape of the quads.
That point at the top starts at the ASIS,
Which is off to the side, not in the centre of the leg.
At the knee, you want to use more straights to
indicate bone and all the vertical tendons in that area.
The vastus medialis is the lowest of the bunch.
The vastus lateralis is a bit higher up
on the outside.
The rectus femoris starts even higher
at the top of the quad tendon,
and goes up at the same angle as the femur.
The quad tendon
is another place to look for asymmetry.
I want to remind you guys about the triceps tendon.
Remember how it was diagonal
and had a roof with a short and long side?
The quad tendon is similar.
It looks like a little house tipping over to the lateral side,
with an asymmetrical roof.
The short side is this top plane
that the rectus femoris attaches to,
and the long side is the edge that the vastus lateralis
attaches to.
The vastus medialis connects to the
medial wall, and since it's so low, it has a tendon
That attaches along the side of the patella, as well.
The quadriceps tendon varies from person to person,
in proportion and shape.
So, you get a little artistic license here.
Basic Forms
Ever notice how women in comics will
often be posed to accent very specific...
...body parts?
Well, one of the more common poses for male superheroes
is all about the quads.
Look at this one.
It's pretty much just quads, delts and fists.
In the adductors lesson,
We grouped the quads and hamstrings into one large mass,
to focus on the adductors.
The quads take up most of that large mass.
The quads are huge,
and on a huge person, they're even huger.
(HULK SMASH!)
The quads span most of the front of the leg,
and a really large chunk of the side of the leg.
The side is defined by the vastus lateralis,
and is usually fairly flat.
The rectus femoris bulges out in the middle.
In a cross-section lower down on the leg,
Just above the knee,
it's the sides that bulge out more.
We have that bread slice shape as a cross-section.
The vastus medialis and vastus lateralis
Are the muscles on the sides that make that
rounded top part of the bread slice.
This quad tendon in the middle
is flat in this section.
On large hunks, it can even be recessed
as the muscle bellies bulge around it.
The tendon is thin, so when the knee is bent
and the tendon is stretched, you can see the femur's
pointy lateral condyle through it.
The medial condyle is covered by the
mass of the vastus medialis.
Vastus Medialis
The vastus medialis is a very prominent teardrop shape
on the inside just above the patella.
You'll commonly see a sharp edge
where it ends at the bottom.
Even on an average, non-muscular person
who's just standing around,
You'll often see a distinct furrow above the kneecap
where the medialis ends.
The musculature blends together,
but the attachments are defined.
The medialis is the muscle that the
sartorius wraps behind,
before it comes back around to the side of the tibia.
So make sure you don't confuse this whole mass
As the vastus medialis.
It ends here, above the patella.
This is the bundle of tendons we learned about
last time, from the sartorius, gracilis
and hamstrings.
Vastus Lateralis
The vastus lateralis is the largest of all the quads.
In profile view, vastus lateralis
looks like a large football high on the leg,
with its top point at the greater trochanter,
and bottom point just above the patella.
The side plane is flat...ish,
and when flexed, can flatten even more
and get this sharp turn along the front edge.
On a crazy buff guy like this,
you'll see some really intense diagonal fibre striations.
Also remember the vastus lateralis
can be vertically indented by that iliotibial band
We learned about in the butt lesson.
Rectus Femoris
...Not that rectus.
The rectus femoris has two bellies.
On most people you won't see that separation,
but on athletes, it's very obvious.
The lateral belly is higher up,
and more forward than the medial belly.
The rectus femoris defines
most of the contour from side view.
As a final note, I want to come back to the
similarity between the quadriceps and the triceps.
They both have a low medial head,
and a high lateral head from the body of the bone,
and a long head that originates on the torso
instead of the limb.
They both have large tendinous zones
at their insertion, and they both
straighten the limb.
I find these echoes through the body really neat.
In premium, we go into a lot more detail about the quad muscles
and some interesting things you'll see on the surface.
Get the full anatomy course at proko.com/anatomy.
In the next lesson,
we'll learn about the biceps of the leg,
the hamstrings.
Until then, here's your assignment.
Your assignment is the same as last time,
except now with quads.
Do quick sketch of the legs from the model photos
I provided in the description below.
Start with a gesture, then focus on
drawing the forms of the quads.
In premium, I'll show you how to draw all the assignment photos,
so you can check your work.