Lines that define the shape of the human body are those we most notice.
The human body is our yard-stick. To decide how big or far away something is we can have someone stand beside it. We quickly learn to recognize the human form, above all else, as our pre-emminent shape, then we may look for details, male, female, child, adult or aged. We have a great commonality of experience when differentiating the subtleties of the human body, and so it is with drawng. There are many lines or edges in nature but our understanding of them evolves from our first understanding of the lines that define the human body.
Note the little multiple bulbus shapes and lines and how these indicate the soft almost cellular nature of the flesh. The multiple folds and lateral creases typify this in both the face and body.
In my portrait of Tom Ellison (above) the fully rounded shapes begin to appear as fat and muscle combine. Of course the 'adolescent' can change shape quite 'sharply', almost overnight, and their spurts of uneven growth can give them some unusual, if momentary forms. I remember being quite worried myself, once or twice.
OK, this is fairly obvious, even if a little more subtle than the generalized shapes. The male has muscle defined with less fat therefore a little' flat' on the 'tops' of the muscle. There is no hint yet of the concave lines that will begin to appear later. The female shape in the above example has almost a 'male' line on the tilted upper left hip though it is more of a skeletal or joint definition than flesh. I will say more about that later.
As fat disappears and muscle shrinks so the previoulsy convex edges become slightly concave and the gaps at the joints become more prominent. It is more important for artists to study the skeletal structure when painting or drawing mature or older humans or animals.
Next, and a rarity in portraiture and full body paintings, is the aged body's description as an edge. This is the most unflattering and not one portrait painters or photographers would push you aside to witness. It must be noted however, fashion photographers, fashion houses, et al, who are intent on finding models that bear a close resemblances to perambulating coat hangers are not adverse to this anorexia look. They however, use it more for purposes of ambiguity and decadent fascination, and that I will explain later on.
STUDENT ACTIVITY: Make your own series of four drawings of some part of the human anatomy that ages. Teachers should be careful not to discourage the more outrageous selections, but once started the pupil should be made to finish (or explain why not). Allow 40min.