Relief and Hollow at the Bends of a Limb's Joints
A painter's precept on drawing joints, with a plumb-line and perspective figures
On the right-hand page Leonardo notes that at the last bends of any limb's joints every relief turns into a hollow, and every hollow into a prominence when the limb is fully extended, warning that those who trust their own invention rather than imitating nature make grave errors here. A margin note names a vertical 'reverticolo' or plumb-line, drawn as a small figure. The facing sheets also carry geometric figures, including a spiral of points, an inverted cone divided by horizontal lines, and a lettered square (a b), which the transcription does not cover. The pale mirror-written text shows through under transmitted light.
On this page
Relief and hollow reverse at the bends of a limb's joints
Leonardo observes that at the last bends of the joints of any limb every relief changes into a concavity, and every such concavity becomes a prominence when the limb is fully straightened. He warns that whoever lacks this knowledge, trusting his own talent instead of imitating nature, makes very great errors, and adds that the variation is greatest in the middle of the sides.
Vertical plumb-line (reverticolo)
A margin note and a small figure name a 'reverticular' or plumb-line, a vertical reference for measuring and aligning the figure. It is set beside the discussion of how a limb's contour shifts between relief and hollow.
Spiral, cone and lettered-square figures
The facing pages bear untranscribed geometric constructions: a lettered square marked a b at upper right, an outward spiral of points, and an inverted, hatched cone divided by horizontal lines. Their form suggests studies bound up with perspective and measured drawing rather than the limb text.