[jfrancis]

It's difficult to understand the form of the pelvis. I'm trying to come up with a "recipe" that will help me understand it well enough to draw it in any position from imagination.

In simplest terms, I conceive of it as nothing more than two triangles: a right triangle and an equilateral triangle. (plus the sacrum in the back, which is a third, curved, triangle)

The right triangle I further refine in my mind to think of as more of a lopsided ice cream cone.

Here's my recipe so far. What do you think of it? Do you have one of your own?



1) find the butt dimples. They are the posterior superior iliac spines. (PSIS, in anatomy books) I marked them with the letter A.

2) Drop almost straight down (and a touchforward) to find point B on each side. A and B are ALMOST in the same verical plane.

3) Shoot diagonally forward and up to find the pelvic points, the anterior superior iliac spines (ASIS in anatomy books). They are point C in my figures.

4) Congratulations, you have found the lopsided ice cream cone. I shaded it yellow.



5) find the middle of the pubic arch. It's point D in my figures.

The TRIANGLE formed by the two pelvic points (the two C's) and the D point is a vertical triangle. Those points all touch the same forward wall in a living standing figure. You can miss this fact in the classroom skeleton because the pelvis sags under gravity in the classroom skeleton.

6) Find the acetabulum -- "latin for "the little vinegar cup." -- it's there the ball of the thigh bone goes. It's along the B-C line. I mark the top ot that place with the letter E.

7) Conratulations again, connect B-D-E and you've found the front triangles. I've shaded them green.

That should take you pretty far in conceiving of the form of the pelvis in simple terms.

[Max]

Very interesting! I think this is a good way to achieve the right proportions though I am not sure if knowing the pelvis that exactly is really important.
I make just two circles with a connection between them (loomis)
Anyway, good job.

[spooge demon]

This is great! Just in thinking about it all you are understanding it.

I have been painting a character that is very fat recently, and it is a fun thing to do, as it can help you with your understanding of the skeleton. No matter how much fat is on a person, many of the attachement points of muscles to the skeleton are on the surface, like the butt dimples and such. They are really important landmarks to find, and they are always there if you look.

What also interests me about a person with a lot of fat is the skeleton is not fat. There is a normal skeleton under there (well, it depends on when in life the weight was put on, etc.) And the ironic thing is that the more fat there is, the more the weight of the tissue pulls on the skin and on these attachement points and you can get a feel of the normal skeleton beneath. But the elasticity and strength of the skin have a lot to do with this, a younger fat person has thick, very elastic flesh that can hide a lot of this.

Oh well, end of spew

[jfrancis]

spooge: I came across a quote in one of da Vinci's notebooks recently in which he basically asks, "what are the parts of the figure that remain fixed regardless of whather the figure is fat or thin?" If I come across it again I'll post it here.

I like very much what you've been doing with that fat figure, from what I've seen. When you make a figure with the solid parts right, and then hang the fat on it, it has the "ring of truth." It's like blocking in an accurate figure before adding clothing, rather than using clothing as an opportunity to conceal vaguely conceived figures.

------------

I've been noticing that a further refinement to what I said above is to develop an appreciation for the 2-ply nature of the ice cream cone. Because it is a solid, it has a back surface that does pretty much what I said before, and a front surface that arcs around to merge with the top of the pubic arch, like hands on an Irish claddagh ring -- or a basketball hoop.

[jfrancis]

max: Loomis's disks are a good start, but I like more precision than that.

If I used disks, I'd have to ask, where exactly ON that disk is the upside down V where the sartorius splits off from the tensor fascia lata? That V
"sets the tone" for the placement of the quadriceps group. Where exactly ON that disk do the adducters attach? They fill in the rest of the thigh. How exactly do I deal with the disk in profile? Should I cut off the front and back planes of the disk? The pelvis is so much more truncated in profile than a fully round disk.

Now, I'm closer to the beginning of this journey than to the end of it (as if there ever is an end), so I'm not an expert, but after a while, I think I'd have to refine my disk into something more like a real pelvis.

[agflash]

funny ^^
you explain something i'm learning from one very good book.
Here in germany we have one very famous man who wrote a book about a human anatomy. And he is very good in my eyes, his name is
Gottfried Bammes,
maybe you heard of him.
He explain the anatomy more in construction way, and so are those bodymarks described there. I don't really know if this book is in english too, the german name of it is:
"Die Gestalt des Menschen. Lehr- und Handbuch der K�nstleranatomie"
ISBN: 3-363-00966-6
It's quite expesive but it's worth every cent of it, in my opinion.
He goes more detailed in than some other anatomy-books i knew.
And he also answers the question of where the muscles attach, what form are they, and so on.
Anyway it's nice to see someone who is also that crazy to learn the anatomy so deep. ^^
Keep it up.

[jfrancis]

That book sounds interesting; I'll try to see it. Thank you.

[jfrancis]

I posted a bunch of photos to photobucket. You can find them here:

http://img75.photobucket.com/albums/v228/jfrancis/pelvisPhotos/

They were taken using this plastic pelvis I got as part of a budget disarticulated skeleton. The gray plane against which the pelvis was photographed is a horizontal plane -- it's my living room carpet.