If the arm is extended it decreases by 1/3 of the length between _b_ and _h_; and if--being extended--it is bent, it will increase the half of _o e_. [Footnote 59-61: The figure sketched in the margin is however drawn to different proportions.] The length from the shoulder to the elbow is the same as from the base of the thumb, inside, to the elbow _a b c_. [Footnote 62-64: The arm sketch on the margin of the MS. is identically the same as that given below on Pl. XX which may therefore be referred to in this place. In line 62 we read therefore _z c_ for _m n_.] The smallest thickness of the arm in profile _z c_ goes 6 times between the knuckles of the hand and the dimple of the elbow when extended and 14 times in the whole arm and 42 in the whole man [64]. The greatest thickness of the arm in profile is equal to the greatest thickness of the arm in front; but the first is placed at a third of the arm from the shoulder joint to the elbow and the other at a third from the elbow towards the hand. [Footnote: Compare Pl. XVII. Lines 1-10 and 11-15 are written in two columns below the extended arm, and at the tips of the fingers we find the words: _fine d'unghie_ (ends of the nails). Part of the text--lines 22 to 25--is visible by the side of the sketches on Pl. XXXV, No. 1.] 349. From the top of the shoulder to the point of the elbow is as far as from that point to the joints of the four fingers with the palm of the hand, and each is 2 faces. [5]_a e_ is equal to the palm of the hand, _r f_ and _o g_ are equal to half a head and each goes 4 times into _a b_ and _b c_. From _c_ to _m_ is 1/2 a head; _m n_ is 1/3 of a head and goes 6 times into _c b_ and into _b a_; _a b_ loses 1/7 of its length when the arm is extended; _c b_ never alters; _o_ will always be the middle point between _a_ and _s_. _y l_ is the fleshy part of the arm and measures one head; and when the arm is bent this shrinks 2/5 of its length; _o a_ in bending loses 1/6 and so does _o r_. _a b_ is 1/7 of _r c_. _f s_ will be 1/8 of _r c_, and each of those 2 measurements is the largest of the arm; _k h_ is the thinnest part between the shoulder and the elbow and it is 1/8 of the whole arm _r c_; _o p_ is 1/5 of _r l_; _c z_ goes 13 times into _r c_. [Footnote: See Pl. XX where the text is also seen from lines 5-23.] The movement of the arm (350-354). 350. In the innermost bend of the joints of every limb the reliefs are converted into a hollow, and likewise every hollow of the innermost bends becomes a convexity when the limb is straightened to the utmost. And in this very great mistakes are often made by those who have insufficient knowledge and trust to their own invention and do not have recourse to the imitation of nature; and these variations occur more in the middle of the sides than in front, and more at the back than at the sides. 351.