From the tip of the longest finger of the hand to the shoulder joint is four hands or, if you will, four faces.
a b c are equal and each interval is 2 heads.
[Footnote: Lines 1-3 are given on Pl. XV below the front view of the leg; lines 4 and 5 are below again, on the left side. The lettering refers to the bent arm near the text.]
Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.