In extension the foot normally rests upon the heel, the tips of the metatarsal bones, and the outer side of the sole. In walking, running, or dancing the direction of the weight upon the arches is constantly changing, and it is only through the action of certain muscles that the normal arches are conserved. This healthy condition of the plantar arch can only be maintained by the evenly balanced action of those muscles which surround and strengthen the weak parts of the arch. Dr. Busey’s description of the foot in walking, and the injurious effects of the high-heeled shoe, is as follows: “In walking the heel touches the ground first, and supports the whole weight of the body for a moment. A little later the point of the foot touches, and assists in preserving the equilibrium by increasing the base. During the second movement of walking the heel is raised (see Fig. 27, 2), and the weight of the body is shifted more and more to the center of the foot and toes, the latter spreading and pushing the body forward. This last is the movement which displays to the greatest advantage the suppleness and elasticity of the articulations of the foot, and the adaptation of the arch to receive the weight of the body, and to transfer it to the distal pier, while the body is being moved forward by the same act. It is the execution of this movement which gives to the gait of woman that elegance and those graceful undulations which are so attractive. [Illustration: Fig. 27.—The natural and artificial positions of the foot (Camper).] “The narrow high-heeled shoe, on the other hand, by displacing the supporting base, causes both piers of the double-spanned arch to strike at the ground simultaneously. In consequence of which the gait, instead of being undulating, is stiff and hobbling, and the body advances by jerks. “When standing on the heel bone (_NLM_, Fig. 27, 1), the joint at _K_, and the great toe _C_, touch the support upon the line _A-B_. When the feet are shod according to the present fashion, the line _A-B_ is made to assume the concave form shown in Fig. 27, 3, by _BTu_. The instep is made more convex and rounded, and the foot is actually shortened (see _a-b_, Fig. 27, 3). The constant elevation of the heel places the body of the pedestrian in the same position as when standing upon an inclined plane. Again, the heel is so shaped and located that it forces up the keystone of the arch and weakens the whole structure.” =The Correct Attitude in Standing= (See Fig. 28).—The heels are placed nearly together, the toes pointed very slightly outward, the legs are rigid, the trunk and head are held erect, and the shoulders somewhat back, so that the chest shall expand freely. The arms should hang easily at the sides; the fingers are slightly bent, with the thumbs in front. This position of “attention” can only be maintained comfortably for a very short length of time, since the actively contracting muscles soon tire.