This section is from the book "The Manufacture Of Boots And Shoes: Being A Modern Treatise Of All The Processes Of Making And Manufacturing Footgear", by F. Y. Golding. Also available from Amazon: The Manufacture Of Boots And Shoes.
In infancy the foot is broad at the toes, the line of the inner margin of the feet going outwards from the middle line of the foot. The toes lie forward in the direction of their length, and the heel is small in comparison to the width of the toes. They are also short in length, due to the undeveloped metatarsal bones. During growth, the apparent thickness above the heel-bones disappears, and as the metatarsals progress the foot is more proportionate. The heel becomes thicker, and the tarsal bones develop during the succeeding stages of growth, and if the foot has been well exercised and properly cared for, it reaches its beauty of perfection at maturity, and can be classed in its appropriate type.
The Adult Foot, it should be noted, when properly formed, is straight from heel to toe on the inner side, and is wider across the joints than one inch or so further back. The line ab in Fig. 33 is not so wide as cd, and this must be provided for in lasts. It is not usually done in English-made goods, hence the unsightly wrinkles at the "feather," near the inside joint in a large number of boots and shoes. If the shoe is made to fit at ab, and other things are right, it will prevent the foot from going too forward in the shoe, and compressing the toes. When the instep of a foot is high, the heel of the foot is usually short, and the ankle thicker. The well-developed calf, a well-arched foot, and a graceful step are generally present in the same foot. The projection of the heel-bone, and the variations in ankles, are dependent upon the position of the leg in relation to the foot from an imaginary vertical line at the back of the leg. When a joint is small in girth, the instep and ankle are usually greater in proportion to the joint-girth. A foot that is narrow in sole area may be thick or full above, and, on the other hand, a foot may be slim and measure less in circumference and have a spreading sole-area; so there is a difference between a narrow and a slim foot. The arch of the waist of a foot varies considerably in different feet, and feet that measure the same in girth have a differently shaped arch. A person's occupation will cause a difference in the development of the feet.
The Mode of Walking has a considerable bearing on the character, contour, and development of the foot. There are many opinions as to the correct way of walking and standing. Boots that may be correct to stand in may not be correct to walk in. The walk of a person has an important bearing on the shape of the boot required, and some of the sole shapes that have been advocated by medical men do not prove in practice to be the best adapted for walking.
Camper's Theory * was that the toes are naturally parallel to the line drawn through the centre of the sole and heel, and that the second toe is longer than the others. The sole should be as broad as possible, and the end of the toe should be raised, to prevent coming into contact with stones. The heel should be moderate in height, and placed well under the foot, to sustain the centre of gravity of the body. The toes should turn out in walking or standing.
Meyer's Theory was that all feet are alike in mechanical construction, and that the only differences in healthy feet are those arising from varying length and breadth. A line drawn from the middle of the heel - on the sole - under the centre of the ball, or joint, should pass under the middle of the great toe through its whole length. This line is usually termed "Meyer's line" and is shown in the illustrations in this book as " MM."
Fig. 34. Military Position Of Standing.
On the Best Form of Shoe," by Dr. Camper, Why the Shoe Pinches," by H. Meyer, M.D.
The Military Position of standing is to turn the foot outwards, so that the inside margins of the two feet are at an angle of 45°. It is not the strongest method of standing, and this is explained by the fact that, when the foot is turned outwards, the great toe turns up, and the muscles that straighten the toe and keep it in the line of its length are rendered less effectual when operating on an elevated toe, hence the foot is not in its position of greatest security. In the illustration of this method of standing (Fig. 34), the figure aaa'a' will show that, when the person is pushed from the front, the base at the back (a'a') is insufficient to give a firm support of resistance.
The Four-square Position of standing is the most secure. A line drawn longitudinally through the centres of the tread and the heel of each foot will be parallel. The inner edge of the foot in this method of standing will make an angle of 10° with the central line of the body, or 20° with the other edge of the foot. When standing four-square the arch is most firm, the muscles are in a position to act as "rods," and the base of support afforded by the two feet is the greatest (see Fig. 35).
Fig. 35 Four - Square Position Of Standing.
The Footfalls when walking vary at different periods of life, and also in the two sexes. A rather difficult method of placing the feet on the ground when walking is shown in Fig. 35, but it would give free action to the functions of the foot if it could be adopted. The military style of walking is one that is very tiring, and not calculated to develop the powers of the foot (Fig. 34). Another mode of placing the foot to the ground is illustrated in Fig. 36, where "Meyer's line," M, is parallel to the central line of the body, or the direction taken in progression, CC. It would be an easy way to walk, if the foot-gear allowed the free play of the big toe, and the heels of the shoe were exceedingly low. If the inner edges of the feet are made parallel to the line of direction, another variation in walking is exhibited, as seen in Fig. 37, where the line LL is parallel to the central line CC. The most practical method of allowing the foot to fall on the ground is shown in Fig. 38, where the "lines of muscular action" are shown parallel to each other and to the direction of walking. This allows a four-square basis of support to be maintained (aaaa), and the muscles on either side of the foot abduct from and adduct to this line, while full advantage of the buttress projections of the outside joints is taken; further, it accords with shapes of soles that have been found in practice to be most effectual to preserve the functions of the foot. This "line of muscular action," XY, is the best middle line to adopt in designing sole shapes.
Fig. 36.& Fig. 37
Fig. 38. How The Feet Should Fall In Walking
The shortness of the legs in children, and the width of the hips in women, make their walk different to that of the male sex.