The Soldier's foot and the military shoe: a handbook for officers and noncommissioned officers ...

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Preface

In the investigation of the Army Shoe Board, which extended over four years and included the critical study of the feet of some two thousand soldiers, the fitting of many thousands of pairs of shoes, and many months of direct inquiry into the causes affecting the shoeing of the United States soldier, it became evident that in very many instances the faulty conditions found were due to lack of information on this important subject on the part of the officers and noncommissioned officers of the line concerned.

The purpose of this book is to supply the practical information on this subject which has not heretofore been available, and without which it cannot be expected that the several factors which must correlate in order to produce the best foot conditions and marching capacity among American troops will be suitably recognized and satisfactorily coordinated.

To Captain William J. Glasgow, General Staff, and First Lieutenant Benjamin F. Miller, 27th Infantry, who, with the author, composed the Shoe Board, and to Captain John R. R. Hannay, 22d Infantry, later added as an additional member, very many of the new points here brought out on the subject of the military foot and footwear must be attributed.

The Army Service Schools, E. L. M.

45328

Contents

Foot Injuries and Marching Capacity .... i

The Anatomy and Use of the Foot 7

The Military Shoe 34

Chapter II. The Anatomy And Use Of The Foot

The human foot is not to be regarded, as seems almost to be the idea with many, as an incoordinating mass of flesh, bone and gristle which may with impunity be crowded into almost any sort of protective covering to form a fleshy peg, more or less similar to a horse's hoof, on which to walk. It is, oft the contrary, one of the most intricate anatomical structures of the human body. Every one of its parts has a definite function, and interference with its normal anatomical relations and development produces a corresponding structural defect or weakness which will always to some extent diminish — and not rarely is completely destructive of — the capacity to accomplish military marching.

Officers of the mounted branches are carefully instructed in the anatomy of the horse, with special attention to the hoof, foot and their related structures. For the cavalryman, it is appreciated that a competent knowledge of the inter-relations and coordinate functions of bone, muscle and sinew form an essential to the proper care and shoeing of the feet of his mount. This truth applies with even greater force to the soldier's foot; which in its structural anatomy is far more complex and delicate than that of a horse or mule, and in addition is compelled to wear a protection which, if poorly fitted, is much more liable to produce marching disability in the man than it is in the animal. It is impossible to eflfectively select and adapt a proper military shoe without a sufficiently comprehensive and intelligent knowledge of the integral and coordinating structures of the soldier's foot which is proposed to cover ; yet study of the elementary regional anatomy of the human foot by all officers — including those specially concerned with dismounted troops — seems to have been practically disregarded in our service. It is of course not necessary that

Skeleton of riihl foot, Ken from aboTe. (From Gray'i AnatomrO

line officers should go into minor details in this respect, or learn confusing medical terms ; but it is not too much to expect that they should at least gain and carry in their minds a general idea of the nature of the more important structures of the foot and ankle, with the individual and collective purpose and use of these parts. Indifference is probably not so much the cause of the lack of proper knowledge in this respect, as is the fact that appropriate attention has not been directed to the matter and the necessary information has_not been readily available in suitable form. The foot has two functions: That of passive support of the body in standing, and use as a lever to raise and propel the body in walking.

The human foot has as its general basis a framework or skeleton, composed of twenty-six bones (See Figures i and 2). Of these, nineteen are the so-called long hones, composed chiefly of hard, firm bony tissues, of smooth surfaces and

Section through fool on title of great toe. (From Volu.)

various sizes, and joining with other bones at their ends only. The remaining seven bones, of various sizes, are composed of bone which is loose and spongy in texture; these bones have the appearance of irregular pebbles, and have

The Soldier's Foot and Ike Military Shoe ii

many smooth facets forming surfaces for joining with adjacent bones, by which each bone is in contact with from four to six others. Fourteen of the long bones above mentioned are small and belong to the toes, while the other five are much longer and form the metatarsus or ball of the foot. The seven irregular and spongy bones form the basis of the foot arch and heel (See Figs. 3 and 4). One of these — the astragalus — articulates with the leg bones to form the ankle joint (See Figs. 3 and 4).

The heel is obviously intended by nature, through both position and structure, to receive the shock of Impact of the foot against the ground and support the greater part of the weight of the body and burden in standing and at the beginning of a new step. (See especially Figs. 3 and 4). The OS calcis, or heel bone, lies almost in prolongation of the line of the center of gravity of the body as represented by the leg bones. It is the largest bone of the foot, is broad and strong, and articulates closely with the astragalus — ^which lies above and in front of it and forms the keystone of the foot arch. The rear prominence of this heel bone is the point of attachment of the tendon of powerful muscles of the calf of the leg, which by their action lift the heel and rear of the foot off the ground and thus accomplish the first movement of the foot in walking. (See F'g- 3)- This heel bone is guarded ^ against injury by an especially thick !— c^ layer of skin, fatty and fibrous tissue and muscle (well shown in (From Figs. 3 and 4), which serve as an efficient cushion between it and the ground. It is held firmly in position and attached to the bone it articulates with (the astragalus), and with othei: bci-cvt'*, -is^JwvKfi

The Soldier's Foot and the Military Shot to it, by numerous strong ligaments and fibrous tissue (Sec Figs. 6 and 7). These attachments and the nature of the articulations of this bone permit of a certain degree of elasticity without true Joint motion. The foot articulates with the bones of the lower leg, forming the ankle joint, through the astragalus. The latter also forms the keystone of the toot arch (See especially Figs. 2 and 7), as it is wedged between the heel bone and the scaphoid bone. It is a large, strong bone, with broad articulating surfaces, in contact with those of the leg bones, which embrace it on each side and support the entire weight with every step. From its position in the foot, its direct ligamentous attachments to other bones are relatively weak, but it receives additional support from the strong ligaments attached to other bones at the ends of the foot arch by which the latter are held together and prevented from spreading — and the astragalus from beirtg thereby forced downunder the body weight. (See Figs. 6 and 7).

The front of the foot arch is formed by the five small bones, viz: the scaphoid, the cuboid, and the three cuneiform bones, together with the five metatarsals. The first five small foot bones are so closely articulated with each other by irregular surfaces, and are so firmly bound together by numerous small ligaments, as to form a compact bony mass, which is, however, capable of a certain limited amount of yielding under pressure which materially assists in lessening the shock to the foot and body which accompanies each s t e p in marching. (See Figs. 6 and

7). It will also be seen (Fig. 5) that the bones of this region not only form part of an arch extending from front to rear but also are so disposed among themselves as to form a secondary foot arch from side to side, thereby materially adding to the strength of the whole. Support to this lateral arch is given by ligaments and the tendon of one of the leg muscles.

From the very slight amount of elasticity and extremely limited relaxation anatomically possible as a result of the relations of the seven round bones of the foot, it is evident that a foot covering can logically be a close fit back of the tarso — metatarsal joint without in any way interfering with the purpose and functions of the foot.

The five long metatarsal bones form the extreme front of the foot arch. (See Figs, i, 2 and 3, and all radiographs). They are firmly held at their posterior ends by ligaments binding them to the round bones of the foot (See Figs. 6 and 7), but the joints so produced are more flexible than those further back in the foot and permit of considerable motion downward (See Fig. 3). But between the shafts of these metatarsals there is no ligamentous union whatever, thus permitting marked spreading of these bones with broadening of the foot under pressure in the interests of greater flexibility, the production of broader surfaces and resulting increased stability in standing and marching. (See Fig. 6 and all radiographs). The frontal ends of these metatarsal bones, especially the ends of the first and fifth metatarsals, form the front of the foot arch (See Figs. 2 and 3). It will be noted (See Fig. 2) that the line of junction of the five metatarsals with the round bones of the foot, which forms the ball, is not square across but extends obliquely from without inward. The result of this oblique articulation, when the foot is pointed to the front, is to naturally tend to throw the weight of the body -on the outer part of the foot, where the structures are strongest. The ball measurement in fitting shoes is taken just in front of this line of articulations, over the bony prominences at the base of the little and of the greater metatarsal bones.

This marked physiological capacity for spreading of tKe metatarsal bones, especially at their anterior ends, tf^ether

with that obviously possible in the unconnected toes, results

in a requirement that any shoe suitable for military purposes

shall be of such form and width in its anterior part as to allow L ^ -«. proper broadening of the foot in

L --^ \ its metatarsal and toe regions to

yC if * j the extent naturally assumed by

— '■ -jA.-* 1 walking. If this be not done, the

foot is narrowed, contact with the ground is decreased, and body equilibrium is impaired. In the natural effort to preserve the latter in too narrow shoes, the man tends to turn his toes out, thereby largely shifting weight from the strong outer margin of the foot so as to fall over the relatively weak inner arch.

The bones of the phalanges or toes (See Figs, i and 2) articulate with their respective metatarsals, and with each other, in the production of joints intended to have a large degree of upward and downward mobility.

This mobility of the toes is naturally greater than that of the fingers of the hand, with all the delicacy of use required of the latter, yet it is completely lost sight of by the average shoe manufacturer. Under pressure and confinement from ill fitting shoes, these highly mobile joints may largely or completely lose their function and the toes their use. Nearly all the muscles of the foot have their anterior attachments to the phalangeal bones or metatarsals, and contraction of these muscles causes the toe to press against the ground while lifting the body, near the end of the step, by pulling the ends of the foot s of Eole of foal.

Fig. 7

arch nearer together and thereby increasing its concavity downward.

The resting position of the weight bearing foot is maintained by the ligaments, which are not elastic and are not

overstretched in the normal foot. These ligaments bind the bones of the foot together. They hold up the foot arch only in the sense that they interfere at a certain point to prevent further spreading and flatten-

ligament; 2, long plantar ligament; 3, plan- ing OI the lOOt arch aS a result of downward pressure.

The manner in which the bones of the foot are bound together by these ligaments, which are the strongest of those in the body, is well shown in Figs. 6 and 7. These ligaments are tough, fibrous and inelastic, and are not intended to give much play to the parts they hold together. It will be observed that while these ligaments are numerous and run in all directions, by far the strongest ones — and those which naturally have to stand the greatest strain — are those which extend from front to rear of the foot arch. It will also be observed that while the sole of the foot is strongly bound together by ligaments, the latter are practically absent (See Figs. 3 and 6) on the upper part of the foot. The practical result of this location and arrangement of ligaments is that the natural tendency of the arch to flatten under pressure is checked at a certain point ; while the absence of ligaments from the upper part of the foot permits of its flexion downward, with raising of the foot arch and a shortening of the distance between the heel bone and the metatarsals as the result of muscular contraction in walking. The relaxation or giving way of these ligaments is necessary in order that flat foot may occur.

But the passive resistance to pressure offered by the ligaments of the sole of the foot is not of itself sufficient to prevent flattening of the arch. Inelastic structures will ultii6

mately tend to yield to excessive pressure which is sufficiently long continued. To provide against this, nature has reinforced p. g these Hgaments with an array of

foot muscles, whose elastic contractions in producing locomotion also serve to take up a large part of the tension due to body weight which would otherwise fall directly on the ligaments. The intricate relations of these muscles to bones, ligaments and each other is clearly brought out in Figs. 8, 9, 10, 11 and 1.2. It will be observed from Fig. 3 that the muscles of the upper part of the foot, which are chiefly concerned in the slight labor of lifting the toes and fore foot, are few in number and of very slight development. However, one muscle of the leg— the tibialis anticus — has its attachment (See Fig. 2) on the under part of the foot arch, and by its contraction operates to heighten and hold up the latter. The muscles of the sole of the foot, on the contrary, are numerous and should be well developed and strong. Not only do they exert necessary tension, but they cushion the more delfZ"%'t% laUr'."' (F?™ Gray"t icate part of the foot and serve to Anatomy.) protect it against injury. It will be

observed from Figs. 8 to 12 inclusive, that there are no less than five distinct layers of muscles of the foot, practically all of which — except the transversalis muscles (See Fig. 10) — extend from the rear of the foot to its front. The outer or first layer of sole muscles (See Fig. 8) practically runs from the heel to the tips of the toes, their contraction resulting in flex-

The Soldier's Fool and the Military Shoe ion of the foot and toes between these two points. The second layer of muscles (See Fig. 9) runs from the heel to the base of the toes, reinforced by the p^^ j,

tendons of certain muscles of the calf of the leg. The third layer of muscles (See Fig, 10) strengthens the metatarsal region and adds additional force to the thrust of the ball of the foot against the ground in Walking, The fourth and fifth layers of muscles, (See Figs. II and 12) with one group of the third, simply serve to prevent too great expansion outward of the smaller metatarsal bones in marching and assist in maintaining the balance of the body. The contraction of all these muscles flexes the sole, adducts the foot and forces the arch to rise. A buffer is thus formed which breaks the shock of impact of the ball of the foot against the ground.

The tendons of muscles operating on the sole of the Muscles of ihe soie of the Foot, secfoot are well protected and are "" "''"" '""" "*" "»<"">■■ not liable to incur injury. Those on the top of the foot, and particularly the one lifting the great toe, are superficial, are thinly covered with soft tissue, and lie directly over bones against which they may be pressed by too tight shoes, with resulting injury and inflammation of the tendons and fibrous sheaths in which they work.

Arteries, veins and nerves are of less practical importance in a study of the anatomy of the foot in relation to the shoe.

i8 The Soldier's Foot and the Military Shoe

The arterial system lies fairly deeply between muscles and tendons, and pressure sufficient to materially affect it would cause such immediate discomfort as to bring about prompt p,j ,p remedy. The same applies to

the nervous system. The veins, however, lie more superficially and may be pressed upon, particularly by shoes too tight around the ankle, sufficiently to cause more or less interference of the return flow of the blood with swelling of the foot below the point of compression.

Examination of normal foot prints shows (See Figs. 13, 14 and 15), as might be expected, that with increased pressure upon the foot there come into play accessory bearing surfaces on its sole. This is particularly evident in the appearance and increase in size of the inked spot, representing the second phalanx of the great toe, which is absent on the first of the above mentioned prints, made by the weight of the leg on the foot; in the second, partially fills the space between the balls

Muscles of the Sole of the Foot, third of the foOt and toe when the layer. (From Griv'a Analogy.) , . i ■

man marches under his own weight ; and in the third almost completely fills this space when the man carries the military burden. The general broadening and lengthening of the foot under these diverse conditions of weight support is also apparent. These facts are important, since when troops are put into heavy marching order under burden, they bring into operation bearing areas of the feet ith the soldJer walking with.

Fig. 15

JJ^ n his back. Compare with I which have heretofore been largely unused and have thereby been protected against friction and pressure. Such areas are covered with relatively soft, thin skin and may be extremely sensitive at the outset of a march; but upon continuance of the march they should become hardened and play their part equally with other more toughened areas in supporting the soldier and his burden. Injury of such accessory bearing surfaces is quite common among soldiers at the outset of a march. It is clear from a summary of the anatomical features of the bones, ligaments and muscles of the foot, that its most important part relates to the foot arch. The latter is a development in man to facilitate his characteristic walking in the upright position. Flat footed apes can walk no great distance in the upright position, and then only with the additional support of the arms. Flat footed men are notoriously unable to march. The foot arch has been shown not to be rigid, but to be a loose structure the bones of which wedge and tighten against each other under pressure from above and opposed by tension from below. The resulting arch is then not what engineers call a solid "segmental arch", but rather a "bowstring arch" in which the center is held up by tension on its ends. This "bowstring" effect of the muscles is greatest at the end of the step. If the pressure from above is greater than the tension exerted by the elastic muscles below, the excess pressure falls directly on the ligaments of the foot. If this excess pressure be long continued, the ligaments will stretch to a greater or less degree and the foot arch fall in proportion. But another factor, so well illustrated in Fig. 3, also has to be taken into consideration, and that is the size of the muscles located within the foot arch. With development of these muscles comes increase not only in their strength but in their bulk — and the larger bellies of these muscles, by more completely filling up the foot arch, mechanically hold up and buttress the latter against falling. Since muscles increase in the transverse diameter of their bellies on contraction — and as these foot muscles practically all run longitudinally — it becomes evident that the contraction of these muscles necessary to accomplish walking will at the same time serve not only to pull the ends of the foot arch together but to push up and support its sides and center. Too much importance therefore can not be placed in developing the foot muscles in preventing foot weakness, and such development is only brought about through their use, which in turn is only possible through proper foot-wear permitting of full function of the foot and the appropriate muscular action on which such function depends.

Muscle tension and balance thus maintain the foot arch in its proper curvature. Where this is lost, the arch tends to flatten, with or without associated pain. But a foot of a type normally presenting a low arch may be quite as serviceable as if it were higher, since the muscle groups maintaining its integrity are satisfactorily performing all the work which is demanded of them. In stout, muscular feet the sole of the arch approaches nearer the ground than in unrelaxed arches with little muscular development ; the diilerence is tK-i*. -«=«is>.

24 * The Soldie/s Foot and the Military Shoe

further loading of the individual with a burden, such as the military equipment, the first described arch remains about the same while the latter readily tends to break down.

Weakening of the foot muscles is one of the penalties of civilization, as walking is less and less a factor in locomotion, while primitive out-door peoples are more or less nomadic and their occupations are not sedentary. The introduction of railroads, street cars and automobiles, has materially interfered with foot development in many. And with lesser need for the use of the foot in walking, came the introduction of deforming and confining shoe types, by which the use of certain foot muscles was interfered with and their consequent atrophy and weakening was inevitable.

From consideration of the anatomy of the foot as a whole, it thus appears that the various structures of the foot form a whole which is both strong and supple ; supple in the forward part and strong and massive in the hinder part. These points must not be forgotten, as they exert a controlling influence on the nature and shape of military footwear which must be provided for the soldier if he is to have a maximum ability for inarching.

The perfect, undeformed foot is found practically only in children and among savage, non-shoe wearing peoples. See Pigs. i6, 17, 18 and 19, in which the God of the famous Greek sculptor, the American child, and the head hunters of the Philippines present approximately the same foot type. As far as soldiers are concerned, the undeformed foot is a figment of the imagination; yet extreme cases of foot deformity, such as are common in civil life, are kept from admission to the military class through the requirements of the recruiting officer. However, in the great number of soldiers' feet examined by the Shoe Board, practically not one was free from some appreciable deformity or blemish. The production of foot injury begins early, and conditions become more serious, exaggerated and give less prospect of recovery with the passage of time. The condition is not so much produced by the mere fact of wearing shoes, as by the wearing of individual sets of shoes which do not fit. All shoes are not necessarily harmful to the feet, but careful attention to the character of the shoe and its subsequent appropriate fitting are both requisite in the avoidance of danger from this source.

The artificial results of deforming footwear, as seen for example in hallux valgus, are so common as to be accepted by many as the handiwork of nature. It is probable that a number of soldiers who regard the shoes issued by the government as "too broad", unconsciously express this erroneous idea.

It is quite apparent from the foregoing that the foot is not at all the rigid structure popularly supposed, to be carelessly jammed into any sort of container, irrespective of the size, shape, and character of the latter. On the contrary, it is seen to be a highly developed member of complex formation and intricate function, every factor of which needs thoughtful consideration in determining its proper covering.

Military or Straight-leg Marching. (After Bradford.)

Having determined the anatomy of the foot, we may next briefly consider how the latter is used in marching (See Fig. 20). Shoes have their effect upon gait, and the shod man does not walk in the same manner as an unshod one.

The Soldie/s foot and the Mitita/ry Shoe ig

Starting from a position, say, in which the sole of the right foot rests squarely on the' ground and is practically supporting the entire body weight, the rear or left foot is just about to leave the ground against which its toes are pressed strongly by their flexor tendons. These toes are spread out and assist in maintaining equilibrium of the body, their bases are raised off the ground, and further contraction of their muscles causes the foot to rise until their tips rest against the ground and give a final push which sends the body further forward and destroys its equilibrium. This push need not be great, as the weight is now practically all supported by the right foot and balance is easily lost. To execute the last movement properly, it is clear that the shoe should be broad to allow for expansion, and its shape such that the great toe can stretch itself out directly forward in continuation of the long axis of the first metatarsal.

As this left foot leaves the ground the force of gravity, acting as a result of the loss of equilibrium in a forward direction, causes it to swing outward and brings it forward to a position under or slightly in front of the body without muscular exertion. From this point the leg is advanced through the distance required for the next step by the action of the extensor muscles and the straightening of the limb. At the same time the toes and front of the foot are pulled up by the muscles of the front of the leg. As the left foot strikes the ground, the body equilibrium temporarily lost is regained again through its support.

The heel strikes the ground first, with the toes pointed upward. The ankle joint is held firmly by the action of the muscular groups; the latter yielding as the center of gravity is advanced, and as more and more weight is thrown on this foot by propulsion . from the right foot. The heel thus forms a fixed point with the ground, above which the body swings in a limited arc — the heel itself rotating until the toes are lowered and the foot rests squarely on the ground. In this last position the left foot is practically supporting all the body weighty which has now been transferred to it from the right foot.

The three chief points of support of the left foot are now the heel, and the heads of the first and fifth metatarsal bones. As in standing the foot arch bends slightly through its articulations yielding under the weight of the body and resumes its natural curve as soon as the foot is raised, so too this same limited joint motion of the arch occurs with every step in marching.

Fig. 21

Flexion or Bent-knee Marching. (After Bradford.)

At this point, action of the muscles of the calf of the leg begins, supplements propulsion of the body from the right foot and lifts the left heel off the ground. In this position the point of support for the arch, and through it for the body weight, is in its anterior portion where the metatarsal bones rest upon the ground; the point of resistance, furnished by the ground and body weight, is on a level with the joint of the instep;