A Treatise on Painting
by Leonardo da Vinci, translated by John Francis Rigaud
Of the Measures of the human Body, and the bending of Members
3998779A Treatise on Painting — Of the Measures of the human Body, and the bending of MembersJohn Francis RigaudLeonardo da Vinci

Chap. XXXIV.The Difference of Joints between Children and grown Men.

Young children have all their joints small, but they are thick and plump in the spaces between them; because there is nothing upon the bones at the joints, but some tendons to bind the bones together. The soft flesh, which is full of fluids, is enclosed under the skin in the space between the joints; and as the bones are bigger at the joints than in the space between them, the skin throws off in the progress to manhood that superfluity, and draws nearer to the bones, thinning the whole part together. But upon the joints it does not lessen, as there is nothing but cartilages and tendons. For these reasons children are small in the joints, and plump in the space between, as may be observed in their fingers, arms, and narrow shoulders. Men, on the contrary, are large and full in the joints, in the arms and legs; and where children have hollows, men are knotty and prominent.