The human foot and the human hand

by George Murray Humphry

The second series of movements—the raising the toes, the turning the sole downwards, and the straightening the foot—are effected by two muscles (F, fig. [12], and G, fig. 13), the tendons (f and g) of which pass, one in front of the inner ankle, and the other in front of the outer ankle, to the respective edges of the instep. These require much less power than their opponents; and the muscles on the front of the leg are, therefore, smaller and weaker than those behind.

A question of practical interest here suggests itself. How is the balance between these antagonistic muscles maintained, and the proper position of the foot preserved? If the muscles which cause the elevation of the heel and the other movements associated with it are so much stronger than those which produce the opposite series of movements, and if, as we know to be the case, muscles are always, even when a limb is at rest, contracting with a certain amount of force, why do not those of superior power gain and maintain the ascendancy, and hold the limb in the position to which they have a tendency to draw it? And why, in this instance, are not the feet kept with the heels raised and the soles inturned and bent? The reply is, that the ill consequence suggested is prevented, and a proper adjustment between the opponent sets of muscles, in this and other parts of the body, is effected through the medium of the nervous system. That system institutes friendly relations, and compels an orderly and harmonious action of the several muscles; and it does so by frequently exerting its influence upon them, keeping them in drill, as it were, and enforcing the habit of yielding in a kindly manner to one another.

Fig. [14].
Club-foot.

You have often observed, and perhaps wondered at, the almost incessant, semi-involuntary and, seemingly, meaningless movements of infants, especially the peculiar sprawlings out of their fingers and toes. Now these are for the purpose of keeping the different sets of muscles in practice and in order, till the will acquires a due control, when they gradually cease. They are going on before birth as well as afterwards; and when they are deficient, or when they take place irregularly, in consequence of an imperfection in the nervous system, the limbs are liable to become deformed. The feet, under these circumstances, are often drawn into the very position I have just mentioned; the sole is turned inwards and upwards, so as never to touch the ground; the heel and the toes are approximated; and the foot rests upon the ground on the outer side, or quite on the fore part, of the instep. Such a condition constitutes one of the most common forms of what is called “club foot.” Children are often born with one or both of their feet thus distorted. Happily, however, if they be submitted in time to the modern improved modes of treatment they may usually be set right. The accompanying woodcut gives a sketch of the foot of a young woman who had not the good fortune to be thus attended to.

The muscles compose the flesh or chief part of the bulk of a limb. The “calf” is almost entirely made up of the fibres of the “calf-muscle.” But at the ankle there are no muscles. As they descend the leg, all the muscular fibres disappear, and there are only tendons. These, though much thinner than the muscles, are very strong; and they are the cords or ropes by which the muscles pull upon distant parts. As they pass over the ankle they are strapped down close to the bones by means of stout sinewy cross-bands, which prevent their starting from their places when the muscular portions pull at them.

Two especial advantages result from this arrangement.

First, the lower part of the leg and the ankle are reduced in size. Thereby the resistance to the passage of the limb through the air is lessened; and when it is upon the ground, the leg is less in the way of the other foot which is swinging, to and fro, beside it. An elegance of shape is also thereby imparted. The “pretty ankle” owes much of its charm to the mode in which the tendons are disposed. How comparatively thick and clumsy would the ankle be if the tendons of the toes took the straight course represented by the line a in the drawing, instead of being bound down, as they are, to the curve of the ankle!

Fig. [15].