from c to a and this happens when the elbow forms a right angle.
[Footnote: See Pl. XLI, No. 1.]
Proportions of the arm (345-349).
345.
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.]
346.
The hand from the longest finger to the wrist joint goes 4 times from the tip of the longest finger to the shoulder joint.
347.
a b c are equal to each other and to the foot and to the space between the nipple and the navel