The traditional wooden manikin has become an iconic symbol for the visual arts. They come in all styles and sizes, yet, it seems, most artists don't actually find them very useful. Their forms don't really resemble those of a real person, and their joints are greatly limited compared to what a real person can do.
So some artists use this guy:
There's also this unforgettable couple:
The simple wooden manikin helps us break down the figure into a few basic forms, and to see that the vast myriad of seemingly curvy and organic gestures are actually made from the relationship of very small number of rigid components, attached by simple joints. But even very subtle gestures require more joint movement than today's standard artists' manikin allows. Some older manikins have hinged shoulder joints, and a manikin I inherited from my mother has rotating hip joints as well. Today's off the shelf manikins have become almost useless so, not surprisingly, no one uses them.
Rather than take this lying down, I modified my manikin, as I did with my plastic skeleton. I made the shoulder sockets into vertical slots, so now the shoulders can raise and lower. Next I unglued the balls of the hip joints, and reattached them with springs. Since the manikin's forms are basically cylindrical (they don't represent real muscles) rotating and swiveling the hips looks the same as it would if they used true ball and socket joints. This means my guy can do great stuff like this:
His shoulders can't move forward and back, though. Stop motion puppet armatures can do this, but lack the rudimentary forms we need. Being able to adduct and abduct the hips (swing them straight out to the side, or in toward one another), means he can also ride a... horse?
An artist friend once told me, "when learning to draw people, draw things that are like people" (I think he in turn had heard this from someone else). It can be great practice to draw manikins from memory as well. You can see how the subtlest changes in angle and position of a few elements create very different gestures:
We read other people's body language naturally and automatically, and unconsciously "pose" our own bodies to communicate things. It's very hard to be consciously aware of what exactly the different parts of the body are doing to elicit the effect. Using a manikin as a drawing subject teaches us how to manipulate the basic building blocks of body language and gesture by stripping out everything else that is irrelevant.