Relative proportion of the hand and foot. From The Notebooks of Leonardo Da Vinci

Study of hands. By Leonardo Da Vinci. Image from www.arch.mcgill.ca/.../winter2001/pham/titre.htm

If you hold your hand with the fingers straight out and close
together you will find it to be of the same width as the widest part
of the foot, that is where it is joined onto the toes.
And if you measure from the prominence of the inner ancle to the end
of the great toe you will find this measure to be as long as the
whole hand.
From the top angle of the foot to the insertion of the toes is equal
to the hand from wrist joint to the tip of the thumb.
The smallest width of the hand is equal to the smallest width of the
foot between its joint into the leg and the insertion of the toes.
The width of the heel at the lower part is equal to that of the arm
where it joins the hand; and also to the leg where it is thinnest
when viewed in front.
The length of the longest toe, from its first division from the
great toe to its tip is the fourth of the foot from the centre of
the ancle bone to the tip, and it is equal to the width of the
mouth. The distance between the mouth and the chin is equal to that
of the knuckles and of the three middle fingers and to the length of
their first joints if the hand is spread, and equal to the distance
from the joint of the thumb to the outset of the nails, that is the
fourth part of the hand and of the face.
The space between the extreme poles inside and outside the foot
called the ancle or ancle bone _a b_ is equal to the space between
the mouth and the inner corner of the eye.
325.
The foot, from where it is attached to the leg, to the tip of the
great toe is as long as the space between the upper part of the chin
and the roots of the hair _a b_; and equal to five sixths of the
face.