Last time we learned a whole bunch of anatomy about the pelvis, and how a bucket can help
us draw the simple forms. Now let's take it a step further and put a pelvis in that bucket.
If you haven't seen the previous episode about the anatomy of the pelvis, you might get confused.
This method of constructing the pelvis from nothing is most useful when you are drawing
from imagination. That's really the goal of this whole course - to set you up to be able
to draw the anatomy of the body from the vision in your mind. You'll be able to construct
the forms starting with the skeleton and build the muscles over that. Premium students, you
can start your first few drawings using the 3d model, but then try to do some from your
imagination. You want to get this construction down well enough that you can do it in your
sleep.
Ok, so let's get started.
Step 1 - The Bucket
I'm imagining a 3/4 front view, pointing to our right. It's not tilted up or down. It's
in it's neutral anatomical position. Remember, a neutral pelvis simplifies to a bucket that
tilts forward. But that doesn't mean the person is actually tilting their pelvis forward from
neutral. This is not neutral. This is neutral.
Let's start with the ellipse of the top cap - the lid of the bucket. The roundness of
the ellipse will be based on how much of the top plane we are seeing. The angle of the
ellipse will depend on the long axis of the bucket. The long axis is the line from the
center of the top to the center of the bottom plane. The angle of the ellipse on a perfectly
round bucket is perpendicular to that long axis.
Now find the sides of the bucket. Make sure you follow the original angle of the long
axis.
Finally cap off the bottom of the bucket.
Step 2 - Cut out a Wedge
After establishing the simple bucket, we need to cut out this wedge shape from the front
top half of the bucket. The edges of the wedge align with some of the landmarks, so the placement
is not ambiguous. I like to find some more construction lines to get the placement of
the wedge precise.
I'll start by gridding out the top plane. Put a dot in the center of the top plane.
Find an angle from side to side. In our case it's horizontal. In some cases, when the pelvis
is tilted or when the horizon is above or below the pelvis, this angle will not be horizontal.
Then find an angle from back to front. I like to continue these lines all around the bucket
as if they are rubber bands. Even ghost them in the back planes a bit lighter.
Ok, so now these lines will help us take out the wedge. The top corners are the ASIS points.
That edge between the ASIS points is ? of the way down from the center to the front.
Put a line parallel to the horizontal line and now we have the ASIS landmarks.
The pubic symphysis is halfway down the front plane. From there, wrap a rubber band around
the bucket.
Drop vertical lines from the ASIS points to that rubber band. Connect these two corners,
and there you go. You've cut out the wedge.
I'm going to find one more construction line before I move on to the next step of drawing
the actual forms of the pelvis. Similar to this front edge of the iliac crest, I want
to find the back edge. This one is halfway between the center to the back. Now, these
2 dots represent the vertical peak of the iliac crest. From there, the crest drops down
toward the PSIS points behind the Sacrum. So, this section of the top ellipse represents
this half of the iliac crest. Not, the entire iliac crest.
Now, we're ready for the final step.
Step 3 - Draw the rest of the %#$@&* pelvis!
Don't worry, I am going to show you how to actually draw this complex pelvis shape in
this bucket...
Let's start from the top and work our way down.
The iliac crest has some thickness, so I'll indicate the top plane.
from these points the crest drops down toward the sacrum, so let's find the sacrum. The
top of the sacrum is ? of the way down the back plane. This vertical line I drew earlier
is the back plane. Ok, so ? from the top is the top of the sacrum.
Now we can drop the iliac crest behind the sacrum. From this point of view the left side
is very foreshortened and the right side is not.
This wedge shape we found is pretty much the final shape. Just round off the corner a little
bit to make some more room for the acetabulum.
From there, go about a 1/3 of the way down for the height of the cartilage. And then
a v shape for the pubic arch.
Follow this arch of the ischium around for a bit and then up toward the iliac crest.
The side plane of the ilium is concave. Widening at the top to the iliac crest and at the bottom
to the acetabulum. The acetabulum is the socket for the femur bone. It's really round and
deep.
And down here, since we're looking at the inside of this form, we'll see this side plane
that shows the thickness.
A softened triangular shape for the hole.
Let's add the sacrum in the back. Draw a rectangular shape representing the top plane of the sacrum.
This top plane tilts forward more than the bucket itself. So this line from back to front
will be more vertical than the line of the back to front of the bucket.
From the top plane, let's extrude a curved triangular form for the rest of the sacrum.
The tip of the coccyx should touch the base of the bucket right in the center.
From this front edge of the sacrum, extend a curve around the inlet and connect it to
the pubic symphysis.
And finally, through this hole of the inlet, we're going to see the back edge of ischium.
There you go! A manageable construction of the pelvis. This pelvis has accurately simplified
forms, accurate placement of the landmarks, and accurate perspective. Basically, this
method of construction enables you to manage the complex forms of the pelvis, while keeping
everything where it needs to be.
Once we are able to do this same thing for the entire skeleton. We will be able to pose
the skeleton as we wish from our imagination. Then, we can attach the muscles to the appropriate
origins and insertions, and we'll have a complete body. All from our mind. How cool is that?
Assignments
So, your assignment for this week is to do 3 drawings using the 3d model. Pose it however
you want and draw it the way I described in this video. Start with the bucket, cut out
a wedge, and then draw the pelvis inside. The 3d model is available to premium students
only. If you're not a premium member, you can download a few screenshots from the link
in the description below. (insert link to blog post here)
Then, after you did 3 drawings from the 3d model, draw 3 more from your imagination.
Upload your drawings to the Facebook group at facebook.com/anatomy4artists. This week
I have 6 more examples of how to draw the pelvis. If you want to become a premium member,
go to proko.com/anatomy to get extended versions of these videos and a whole bunch of other
stuff. That's proko.com/anatomy.
Giveaway
If you'd like to win premium membership to the Anatomy course, check out the description
below for instructions.
That's it, thanks for watching! If you're posting your drawings, use hashtag #proko
and don't forget to follow me on Facebook and Instagram. Also check out the Anatomy
for Artists group on Facebook at facebook.com/groups/anatomy4artists! If you like this video, share it with your
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Proko newsletter. Buh Bye!