US 2227429 A
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' Jem. 7, 1941., D. W. AUSTIN .2,227,429
FOOT BALANCER FOR METATARSAL AND WEAKLFOOT CONDITIONS Filed Oct. 5l, 193B Patented Jan. 7, 1941` PATENT FFECE FT BALANCER FOR METATARSAL AND WEAK FOOT CGNDITION S Dale W. Austin, Hollywood, Calif.
Application October 31, 1938, Serial No. 237,830
My invention seeks to treat the cause of Weakfoot and inetatarsal conditions, i. e., metatarsalgia, Mortons toe, Heloma Mollie in the interdigital spaces, contracted toes with the accompanyiiig Heloma dura, and Hallux valgus, regardless of the heights of the arch involved, these conditions being brought about by an improperly Ibalanced foot.
To comprehend my invention, it is desirable to explain the component parts of the arches of a normal foot, and the proper foot balance for a normal foot when walking in a normal manner, no matter whether this may be considered as with or without shoes and with or without a heel of moderate height.
The anatomy of the foot- Thefoot in order to allow itself to support the weight of the body in the erect posture is constructed of a series of arches formed by the `tarsal and metatarsal bones, and strengthened by the ligaments and tendons of the foot. These arches are the longitudinal arch, and the anterior and posterior transverse arches. For descriptive purposes, the longitudinal arch is divided into a medial and lateral arch. The medial arch is made up of the calcaneous, talus, navicular, and the three cuneiforms, and the iirst, second and third metatarsais. The lateral arch is made up by the calcaneus, cuboid, fourth and fifth metatarsals and two ligaments. The anterior transverse arch is made up by the heads of the iive metatarsals and the posterior transverse arch is made` up by the posterior part of the metatarsals and the anterior part of the tarsus, These arches are strengthened by the intelosseus, plantar and dorsal ligaments, short muscles of the rst and fth toes, and by the peroneus lcngus.
Normal weight support-In the act of normal walking, the calcaneus makes the rst point of contact with the ground, and thereby may be considered as the first weight-bearing point. In the progressing forward movement, the weight is then transmitted through the posterior and middle facets of the calcaneus--whose surfaces incline in the direction towards the cuboid bonewhich transfer the weight simultaneously to the base of the iifth metatarsal bone, so that we consider the culboid-iifth metatarsal articulation together as the second weight bearing point. The Weight then progresses forward along the fifth metatarsal to the fifth metatarsal head, making the third weight bearing point. Thus, on the outer weight bearing arch, we have a small tripod balance between the calcaneus, cuboid-base of the fifth metatarsal and the head of the fifth metatarsal giving the proper stability to the forward motion of the foot. The head of the fifth metatarsal acts as a lever to aid in the contraction of the peronei muscles at this point to thrust the weight in a rolling motion across the heads 5 of the fourth, third and second to the head of the rst metatarsal bone, giving us the fourth weight bearing point.
Thus, we have a great tripod balance between the calcaneus, head of the fifth metatarsal and` 10 the head of the rst metatarsal bone giving the proper balance to the foot as a whole. These four weight bearing points are anatomically identified as being such by their construction. The calcaneus taking the heaviest shock, being the heaviest and strongest bone in the foot. The cuboid, base of the fthmetatarsal articulation taking the next heaviest shock, being the next to the heaviest part of the foo-t. While the fifth and rst metatarsal heads have each two seisarnoid bones which act 20 in a manner similar to ball bearings, to assist in taking the load and distributing it in the proper rolling motion. None of the other bones of the foot are constructed mainly for weight bearing so we will consider these as the four main weight 25 bearing points of the normal foot.
After the great tripod balance has been obtained, the inner spring arch then relaxes to take the shock of the step, by yielding in its articulations particularly by the inward and downward 30 motion of the navicular head, then one rolls forward on the toes completing the step.
Problems of the abnormal foot-In an abnormal foo-t balance, it has been my experience of involvement of the metatarsal area, that there is 35 a pronation of the heel, the motion taking place vin the sub-astragalo joint. This can be identied in the objective diagnosis by the positive Halbing sign, prominent lateral border which can be shown in the Shadowagraph or Pedograph.
The only exception is the rare case of a direct injury to one of the metatarsal heads (example: stepping on a spike). When the Weight first comes down on the heel, this pronation cr tilting of the heel causes the weight to be thrown forward on the spring arch of the foot. Through this, the ligaments and muscles on the inner side of the foot are overstretched, resulting eventually in weakfoot. The height then progresses forward, hitting the inner metatarsal heads directly, 50 giving the foot just a two joint balance. This direct hitting and resulting pressure intsead of the proper motion, causes the majority of metatarsal conditions.
M y solution or remedy for the abnormal foot- A main object and feature of my invention is to employ wedges which will tend to guide an abnormal foot, regardless of the height of the arch involved, so that the weight is approximately carried in the manner designated for the normal foot. To accomplish this purpose broadly, I employ two wedges which may be attached to or built into insoles or used in the shoes for the purpose of giving this guidance. For instance I employ one wedge beneath the medial border of the calcaneus to correct the eversion of the calcaneus and to direct the weight thrust in the normal manner to the head of the fifth metatarsal bone. This wedge thus throws the calcaneus into a valgus position. A forward wedge is used on the opposite or outside edge of the foot extending under the shaft and head of the fifth metatarsal and to a lesser degree under the shaft and head of the fourth metatarsal, -this being tapered to zero at the center of the foot. This wedge directs the weight in the normal rolling motion from the fifth metatarsal head over to the first metatarsal head so that the metatarsal arch functions in the normal manner. The forward wedge throws the forward part of the foot into a varus position. The combination of the two wedges also serves to lock the inner spring arch which assists the accompanying weak foot condition by keeping the foot from elongating.
Thus, this system of wedges, by forcing the foot to function in a normal manner gives the foot the proper opportunity for exercise, which in turn assists further in giving normal balance to the feet.
In severe cases, a pad should be employed to raise the depressed metatarsal heads. For this purpose I employ a pad oval in shape, with the highest portion in the center, and tapering in the same manner toward both ends and tapering less gradually to the sides. This pad should be so placed that its highest part is immediately behind the metatarsal heads thus leaving a tapered portion under the heads and also along the shaft of the metatarsal bones.
A further characteristic of my invention is the incorporation of my balancing principle with the two wedges in an insole construction for shoes in which the wedges for the heel and under the head of the fifth metatarsal are incorporated in an inner lining which may be built into the sole of the shoe. In another form of my invention, the wedges may be incorporated in a foot pad made separate from the shoe and to be inserted therein. In ad-dition my invention may be incorporated in more or less conventional arch supports. With my invention may also be utilized conventional metatarsal pads which give a support directly behind the second, third and fourth metatarsal heads.
My invention is illustrated in connection with the accompanying drawing, in which:
Fig. l is a plan of a shoe partly broken away illustrating in dotted lines the location of my foot balancer wedges, in this case used in conjunction with an arch support.
Fig. 2 is a vertical transverse section on the line 2-2 of Fig. 1 in the direction of the arrows illustrating the wedge adjacent the base of the fifth metatarsal.
Fig. 3 is a vertical section on the line 3-3 of Fig. 1 in the direction of the arrows showing the heel wedge acting on the opposite side of the foot.
Fig. 4 is a plan of an insole taken in the direction of the arrow 4 of Fig. 5, this being of the type having a central metatarsal pad.
Fig. 5 is a section on the line 5--5 of Fig. 4 in the direction of the arrows showing the front outside wedge.
Fig. 6 is a section on the line of Fig. 4 showing the heel and inside wedge.
Fig. 7 is an imprint of a normal foot showing the normal tripod type of foot balance.
Figs. 8 and 9 are respectively imprints of an abnormal flat low arch foot and of an abnormal high arch foot, illustrating the points and lines of abnormal balance and in dotted lines, the location of my corrective wedges with points indicating a normal tripod type of balance.
Referring first to Figs. 7, 8 and 9, Fig, 7 shows the imprint made by a normal foot, such as made by the barefoot on transfer paper in the action of normal walking. The first point of contact A, which is the first weight bearing point is directly below the calcaneus. In the progressing forward movement the weight is then transmitted through the posterior and middle facets of the calcaneus -whose surface is inclined in a direction towards the cuboid bone which action transfers the Weight simultaneously to the base of the fifth metatarsal bone so that the cuboid in fifth metatarsal articulation may be considered the second bearing point B, these points being connected by the line II. The weight then progresses forwardly along the fifth metatarsal to the fifth metatarsal head making the third bearing point C, this being along the line I2. The dotted line from A to C designated as I3 may be considered with the lines II and I2 joining the points A, B and C as forming a small tripod balance, this being between the calcaneus, the cuboid base of the fifth metatarsal and the head of the fifth metatarsal thereby giving the proper stability to the forward motion of the foot. The head of the fifth metatarsal acts as a lever to aid in the contraction of the peronei muscles at this point to thrust the weight in a rolling motion across the heads of a fourth, third and second to the head of the fifth metatarsal bone, thus giving the fourth point of balance D, the rolling action being along the line I4 joining the points C and D. A dotted line I5 joining the points A and D may be considered as forming the long side of a triangle in which as the point B is so near the line I3, the lines II and I2 may be considered in a straight line, the tripod support thus being along the lines joining A and C, C and D and D and A. Of course the line C is bridged by the high portion of the arch of the foot but when an arched shoe is worn, a considerable weight is carried along this line, At any rate, there are the three major points of support and balance designated A, C and D forming a triangle in which the angle at C is slightly greater than a right angle. The second point of balance B however is important in carrying part of the weight.
The four bearing points A, B, C and D are anatomically identified by their construction as conforming to this impact and distribution of weight, the calcaneus which takes the heavy shock being the heaviest and strongest bone in the foot, the cuboid and the base of the iifth metatarsal articulation taking the next heaviest shock and being the next to the heaviest part of the foot, this being at the point B. 'I'he fifth and first metatarsal heads have each two seisamoid bones which act in the manner similar to ball bearings and assist in taking the load and distributing it in the proper rolling motion. Due 75 to the fact that none of the other bones of the foot are constructed mainly for weight bearing, we can consider these as the four main weight bearing points of the normal foot, however bearing in mind that the main form of tripod may be considered as dened'by the points A, C' and D.
In the abnormal flat arched foot of Fig. 8, the arch is so weakened that a large surface of the foot contacts the ground, however, the first weight bearing point A is usually closely in proximity to the point A of the normal foot, however the weight is transferred to the point E which varies in position usually between the heads of the second or third metatarsal, the line of transfer of pressure being indicated by the single line iii. In this illustration the normal points of balance are indicated by the points B, C and D. With this type of foot without correction, there is not developed a true tripod type of balance.
In the abnormally high arched foot of Fig. 9, the imprint due to the high arch leaves a space between the fleshy part at the heel and underneath the ball of the foot. In this case the initial point of pressure or weight support A is approximately the same as in the normal foot. The second Weight bearing point is usually so close to the normal point D that this is designated by the same letter, the connecting line being indicated by the line I joining A and D of Fig. 7, however in these abnormally high arched feet the second point of weight support may shift considerably towards the head of the second metatarsal. Thus there is a weight thrust on the inner part of the high arch which causes a strain usually eventually weakening the foot or giving distress through pain or difculty in proper walking.
While these various points of weight support and the transfer of weight have been defined relative to the action of walking, they are in substantially 4the same position when a person is standing normally. Thus in the normal foot the main pressures due to the weight are along the lines connecting A, D, C and D and for the abnormally fiat or high arched foot, the weights are mostly along the straight lines illustrated which give an uneven balance. In order to correct such uneven balance, both in walking and standing, I endeavor to develop a twist in the foot by employing wedges. These wedges may be of diiferent shape and size dependent on the particular foot condition, however, I employ a main heel wedge designated 20. Such wedge has its high side on the inside portion of the 1' heel and tapers to a feather edge towards the center portion of the heel and also usually tapers towards the rear and the front of the heel. Such a wedge therefore gives an angular turn or twist to the portion of the foot at and adjacent the heel and brings the cuboid and the fifth metatarsal in a better position to receive the transfer of Weight. The second or forward wedge 2| is located approximately under the head of the fth metatarsal and may extend towards the rear of the foot as far as necessary and also towards the toes. These Wedges have their high side on the outside of the foot and thus give a twist to the bones of the foot in an opposite direction to that of the wedge 20. This forward wedge thus raises the head and in fact the whole of the fifth metatarsal and consequently the position of the heads of the fourth and at least the third metatarsals. The wedge is tapered towards the center of the foot and also towards the toes and the middle portion of the 'made up `in a series of pads having wedges of different heights.
' In Figs. 1, 2 and 3 I illustrate the manner in 5 which the balancer wedges are fitted to a shoe, an, insole or an arch support. In this illustration the shoe is designated by the numeral 35, having the heelv portion and the portion 3l which supports the ball ofthe foot, the toes extending towards the toe 38 of the shoe. The sole is indicated at 39 and the heel at 40 and for sake of illustration the bottom and top of both the sole andthe heel are presumed to be parallel and to rest on a horizontal surface. Adjacent the heel I incorporate the inside wedge 42 and adjacent the :forward portion of the foot and on the outside I fit the wedge 43. Each of these wedges `has a high outer edge indicated at 44 and 45 and tapers to inner feather edges 461and 41. These wedges also taper at the respective front and rear edges designated 48, 49, 5l] and 5l. The size of the wedges of course depends on the particular abnormal foot condition. The Wedges are preferably made of corn-` pressed cork but many other materials may be utilized. Where desired these wedges may be built directly into the shoe. They may be placed directly on an under-sole liner 54 and have a covering of an upper sole liner 55, these being made of liner fabric or a suitable material.
The illustrations of Figs. 1, 2 and 3 also show the manner in which my balancer wedges may be built into a typical arch support, this arch support being defined by the bottom covering 54, 3
the upper covering 55 and having a metal strap extending longitudinally, this being secured in the padding or built up material BI of the arch support. At the forward end of this strap I illustrate a conventional metatarsal pad ,62, this be,- ing somewhat oval shaped and usually made of soft rubber tapering to a feather edge indicated at 63 at the periphery. The forward wedge 43 is illustrated as overlapping and fitting underneath this metatarsal pad and extending towards the metal strap El). By this construction the foot has the benefit of a more or less conventional arch support coupled with the balancer wedges at the heel on the inside part of the foot and underneath the fth metatarsal and possibly the fourth metatarsal bases. The wedges therefore give a twist to the foot. Ihe heel is given a twist throwing the weight outwardly to direct this more along the line underneath the fifth metatarsal from the heel towards the toes and the forward portion of the foot is given a tilt inwardly, thus bringing a point of support more nearly as indicated by the point B of Fig. 7.
This construction therefore brings the distribution of weight more into the tripod or triangular form as illustrated for the normal foot in Fig. '7.
In the construction of Figs. 4, 5 and 6, I illustrate a typical so-.called metatarsal pad 'l0 in which the heel portion is indicated at 'l I, the forward portion at 'l2 and having a conventional metatarsal pad 'I3 tted below the cover or sole portion 14. This metatarsal pad is as above mentioned usually of rubber tapering to its peripheral edges and somewhat oval in section.
The portiton of the pad following the outside edge of the foot is indicated at 'I5 and that following the inside portion of the foot 16. The forward wedge is built underneath the cover material 'I4 and cemented thereto. The feather 75 inner edge 8| extends partly underneath the metatarsal pad 13, the thick edge of the wedge being indicated at 82. The portions 83 and 84 of the wedge are tapered to a thicker feather edge. The rear wedge 85 has the thick portion 86 on the outside and tapers to a feather inner edge B1 which continues to the rear portion 88 and the front portion 89. This wedge is also xcemented to the cover material 14 which is usually a thin strip of leather.
The shoe lining pad of Figs. 4, 5 and 6 may thus be fitted in a shoe and function in operation the same as the wedges of Figs. 1, 2 and 3, the heel wedge giving a twist and tilt to the heel portion of the foot, this beingA a tilt outwardly and the forward wedge 80 gives a tilt inwardly, thus tending to bring the support of weight along a line from the heel to the base of the fifth metatarsal as in the normal foot. When this is accomplished by use of the proper wedges there is then developed a substantially three-point support as indicated by the points A, B and C of Fig. 7 and the weight being carried as above mentioned along the line of the fifth metatarsal from the heel and across the ball of the foot from the base of the fth to the base of the rst metatarsal.
Various changes may be made in the details of the construction without departing from the spirit or scope of the invention as defined by the appended claims.
1. In a foot balancer a shoe having a shoe sole and a posterior and an anterior wedge positioned on the sole of the shoe, the posterior wedge being located adjacent the inside portion of the heel of the shoe and positioned to raise and tilt the calcaneus to a valgus position, the anterior wedge being located contiguous to the outside y 40 portion of the shoe on the opposite side of the medial line and positioned to raise at least part ofthe shaft and head of the fifth metatarsal and tilt such shaft and head to a varus position, both wedges tapering from the side towards the longitudinal medial line and tapering to a convex curved edge terminating at the forward and rearward portions of each wedge, the shoe sole having a distinct portion without any means to tilt the foot considered longitudinally between the extreme rearward portion of the anterior` wedge and the forward portion of the posterior wedge whereby the portion of the foot at and adjacent the instep may assume its natural position.
2. In a foot balancer a foot pad of thin exible material, substantially of uniform thickness shaped to fit a shoe, the combination of a posterior and an anterior wedge on opposite sides of the medial line, the posterior wedge being located adjacent the inside of the heel portion of the pad, the anterior wedge being located contiguous to the outside portion of the pad at approXimately the position occupied by the outside portion of the ball of the foot, both Wedges having a taper to a thin edge towards the longitudinal medial line of the pad and having a continuing taper toward an edge forming a convex curve to the forward and rear portion of each wedge, the posterior wedge being constructed and adapted to raise and tilt the calcaneus of the foot towards a valgus position and the anterior wedge being constructed and adapted to raise at least part of the shaft and head of the fth metatarsal of the foot and to tilt such shaft and head towards a varus position, the shoe pad having a distinct central portion of uniform thickness considered longitudinally between the forward edge of the posterior wedge and the rear edge of the anterior wedge without any means to tilt the foot whereby the portion of the foot at and adjacent the instep may assume its natural position over such central portion of the foot pad.
DALE W. AUSTIN.