Limbs That Swell or Shrink When Bent; Muscles in Action
Only the knee thins in bending; the whole body drives a powerful arm
Continuing the study of joints, this leaf notes that among flexing limbs only the knee grows thinner when bent and thicker when straightened, while every other joint thickens in bending. In nude figures at work, Leonardo advises revealing the muscles only on the side that drives the action, leaving the rest more or less pronounced according to their effort. A final chapter argues that an arm gains its most powerful and far-reaching motion when the whole body first turns away so the other limbs snap it back; two small struggling figures, a and b, illustrate this at the lower right.
On this page
Only the knee grows thinner when bent
Among the limbs with bendable joints, only the knee diminishes in thickness when bent and thickens when extended. All other limbs of man thicken in the bendings of their joints, except the joint of the leg.
Show the muscles only where the limb does the work
In nude men laboring in various actions, only those muscles on the side that moves the acting limb should be revealed, while the other limbs are more or less pronounced in their muscles according as they labor more or less.
A powerful arm is driven by the counter-turn of the whole body
The arm will have the more powerful and longer movement which, removed from its natural position, has the greater adherence of the other limbs to draw it back where it wishes to move. So the man a moves his arm with the tract e and carries it into the opposite position by moving with his whole person into b.