flattened by the pressure from above; and, consequently, becomes lengthened. When, however, the foot is allowed to hang free, the curvature of the arch is increased. At every step in walking also, when the foot is raised from the ground, the curvature immediately becomes greater through the action of the muscles.
The toes lie in front of the metatarsus, and are connected with it by joints. Each of the smaller toes has two joints,—the great toe only one.
The great toe plays by far the most important part in walking; because, when the foot is raised from the ground with the intention of throwing it forwards, we first raise the heel, then rest for a second on the great toe, and in lifting this from the ground the point of it receives a pressure which impels the body forwards. Thus, in raising the foot, the whole of the sole is gradually as it were "unrolled" up to the point of the great toe, which again receives an impetus by contact with the ground. The great toe ought therefore to have such a position as will admit of its being unrolled in the manner described; that is to say, it must so lie that the line of its axis, whenn carried backwards, will emerge at the centre of the heel; and this is its position in the healthy foot. The sole of an almost sound foot is given in Figure 3, and the true position of the great toe is indicated by the dotted line. This relation is still better brought out in Figure 4, which represents
