Muscles in Movement and When to Show Them
Which muscles vanish or swell in motion, and the rule against showing every muscle on a figure
A text page from the Trattato della pittura, Book Three, on the depiction of muscles in the moving body. Leonardo observes which reliefs disappear or stand out as the arms rise and fall and the flanks bend, noting the shoulders, flanks and neck as the most variable joints. A series of aphorisms drawn from his Libro A holds that youthful limbs should not show pronounced muscles, that a muscle grows higher and thicker the harder it works, and that the central lines of bending limbs never keep their natural length. The page ends by opening the rule that not every muscle should be made evident unless the figure is in great exertion.
On this page
Which muscles disappear in movement
In raising and lowering the arms the breasts flatten away or stand out in greater relief, and the reliefs of the flanks change as the body bends outward or inward. The shoulders, flanks and neck vary most of all the joints because their motions are the most changeable, and a separate book will be devoted to them.
Muscles grow evident with fatigue (Libro A, folio 14)
The limbs of the young should not show pronounced muscles, for that is a sign of matured strength absent in boys. The muscles worked in greater effort become more evident, and a fatigued muscle stands higher and thicker than one at rest, while the intrinsic central lines of bending limbs never keep their natural length.
Do not show every muscle
Thick and broad muscles are given to powerful men whose limbs suit such a disposition. But do not make all the muscles of your figures evident unless they are engaged in great exertion, for the chapter here opens the rule against over-marking them.