Foot Balancing Surface For Shoes

Abstract

The inner surface of a shoe which contacts the plantar surface of the foot is contoured to include a posterior, concave area having elevated side walls and adapted to receive and support the os calcis and restrain the same from lateral or medial movement with respect to the shoe, and a raised area for supporting the plantar protuberance of the fifth metatarsal bone. The surface preferably includes a raised, medial area intermediate the ends of the shoes and adapted to support the medial, longitudinal arch of the foot, and an anterior, convex portion adapted to support the anterior transverse tarsal arch. Disclosed also is a device for insertion within a shoe to provide the above-described surface.

Description

The present invention relates generally to foot wear, and more particularly relates to means for achieving balance of the foot within a shoe.

My previously issued U.S. Pat. Nos. 2,238,366; 2,252,936 and 2,628,440 each relate to the support of the foot within a shoe, and set forth my theory that there is a single primary bone arch in the normal human foot which extends from the plantar region of the os calcis to the anterior plantar portion of the first metarsal. These two areas are the main weight-bearing contacts of the foot. Laterally of a line joining these weight-bearing areas is another important weight-bearing contact which is the plantar protuberance of the posterior end of the fifth matatarsal. Although the last-mentioned plantar protuberance does bear some weight, I believe that its primary importance in walking is to serve to "rigidify" or "lock" together the tarsal bones, including the cuboid, the first, second and third cuneaform bones, and the navicular bone. As the foot rolls forward in a walking motion, the pressure on the plantar protuberance of the fifth metatarsal is reduced, but the locking action thereof is maintained by pressure contact of the forepart of this bone on the walking surface. The fourth, third and second metatarsals act primarily as auxillary braces standing out from the tarsus to assist in the general balance of the foot.

In my U.S. Pat. No. 2,628,440, I point out that by proper support of substantially the entire metatarsal region, and particularly the fifth metatarsal, muscle fatigue and ligament strain may be greatly reduced. I find now, unfortunately, that with the high heels that are fashionably predominant in both ladies and men's shoes, the primary weight-bearing area of the foot is the tarsal area; that is, weight is not distributed properly between the tarsal and heel areas, and do not support the anterior metatarsal arch. Such shoes permit the heel of the foot to move somewhat from side to side in the shoe and permit eversion of the foot with respect to the shoe. Such movements tend to "unlock" the tarsal bones and allow the heads of the metatarsals to drop down, giving rise to discomfort and fatigue. A device which would reduce or eliminate such movements, and which would incorporate the beneficial features of the devices of my previous patents, would be most beneficial.

It is thus an object of my present invention to provide a shoe having an inner surface adapted to contact the plantar surfaces of the foot which enables weight to be borne by the heel as well as the forepart of the foot during walking. It is another object of the invention to provide the aforementioned surface capable of substantially positively preventing unlocking of the tarsal bones during walking, even when high heeled shoes are worn.

It is yet a further object of my invention to provide a surface such as that aforementioned capable of evenly distributing the weight of a person across the plantar surfaces of the foot during walking. It is yet another object of the invention to provide a device in the form of an insert which may be placed upon the insole of a shoe and which is contoured so as to positively lock together the tarsal bones during walking.

Briefly, the present invention in one embodiment relates to a shoe having an inner surface contoured generally to the plantar surface of the foot. The shoe surface includes a posterior, concave area having side walls adapted to receive and support the rounded plantar surface of the os calcis and to restrain the same from lateral and medial movement with respect to the shoe; and a raised area for supporting the plantar protuberance of the fifth metatarsal. Preferably, the surface includes a raised, medial area intermediate the ends of the shoe and adapted to support the medial longitudinal arch of the foot to restrain eversion of the foot with respect to the shoe. Also preferably, the surface includes an anterior convex portion adapted to support the anterior transverse metatarsal arch. As a result, the foot is comfortably balanced within the shoe so that the tarsal bones do not unlock during walking and so that weight is borne by the heel of the foot as well as by the tarsal plantar surface thereof.

In another embodiment, the present invention provides a device in the form of an insert which may be placed upon the insole of a shoe and which is contoured as above-described.

In the Drawing:

FIG. 1 is a top view of a shoe the invention showing the contoured surface thereof which contacts the plantar surfaces of the foot, the contoured shoe surface being shown, for ease of explanation, in the form of an insert represented by solid lines, the forepart of the shoe being represented by dashed lines, and a skeletal diagram of bones of the foot being shown in dotted lines;

FIG. 2 is a cross sectional view taken along lines 2--2 of FIG. 1; and

FIGS. 3, 4 and 5 are cross sectional views taken respectively along lines 3--3, 4--4 and 5--5 of FIG. 1.

Referring now to FIG. 1, a shoe 10 is depicted generally in outline having an insert 12 therewithin which is generally contoured to the plantar surface of the foot. As depicted, the insert 12 extends throughout the heel and mid portion of the shoe, but terminates short of the shoe tip so that the distal end of the first metatarsal rests upon the insole 14 of the shoe, as do certain of the phalanges of the first, second and third metatarsi. The forward edge 16 of the insert is feather-edges so as to rest upon the insole surface 14 without an abrupt contourchange. The other sides of the insert are contoured to fit snugly against the side walls of a shoe. Because the inerst is somewhat narrower in width near its midpoint than at its heel portion, the insert is normally restrained from sliding forward when placed in a shoe. The under surface of the insert may be attached to the insole of the shoe by a suitable adhesive or the like, if desired.

With reference to FIGS. 2 and 5, preferably neither the top nor the bottom surfaces of the insert are flat. For ease of description, the plane defining the surface of the insert which rests upon the insole at the heel portion of the shoe (designated 18 in FIGS. 2-5, inclusive) will be designated the bottom surface of the insert. The posterior portion of the upper surface 20 of the insert has centrally thereof a hollowed depression or concave area 22 which is shown best in FIGS. 2 and 3. The depression 22 is bounded by side walls 24 such that the depression closely receives and supports the rounded plantar surface of the heel bone (os calcis) therewithin and prevents this bone from medial or lateral movement within the shoe. The raised walls 24 also serve to restrain the heel bone from slipping forwardly or rearwardly in the shoe, and tend to eliminate "wobble" (inversion or eversion) of the foot within the shoe. The support which the depression 22 thus lends to the os calcis is of great importance, since it tends to anchor the os calcis therein and properly positions the remainder of the foot upon the insert 12.

The anterior wall 26 of the heel depression 22 extends forwardly and upwardly to terminate in a substantially planar elevated plateau 28 which extends substantially the length of the medial longitudinal arch of the foot. The upper surface of the plateau 28 is broken by convex protuberances 40 and 42, which will be explained in more detail below. Continuous wall 30 joins the plateau surface 28 to the upper surface 32 of the insert, as shown best in FIGS. 4 and 5. In FIG. 1, line 34 represents the outer periphery of the plateau, and line 36 represents the intersection of the wall 30 with the upper surface 32 of the insert. Except in the area of the elevated protuberance 40, the plateau 28 extends medially to the edge of the shoe, as shown in FIG. 1. The upper surface 32 of the insert which laterally bounds the plateau 28 is adapted to support the plantar protuberance 34 of the fifth metatarsal 36, preventing this protuberance from falling downwardly to the insole surface to "unlock" the tarsal bones.

The anterior portion of the fifth metatarsal, and the phalanges thereof together with the distal phlanges of the fourth metatarsus, are supported in an elevated position by protuberance 44 which extends downwardly from the under surface 18 on the insert. This protuberance 44 is approximately trapezoidal in shape (FIG. 1), and is thicker at its lateral end 46 than at its medial end 48, the lateral end terminating at the lateral edge of the insert. Thus, as the foot rolls forward in a walking motion, the distal end of the fifth metatarsus, and the phalanges carried thereby, are supported in an elevated position so that the bones of the tarsus remain locked throughout a walking stride.

Positioned intermediate the ends of the shoe is a raised, convex mound or protuberance 40 which medially abuts the medial wall of the shoe as shown at 50 in FIG. 1 and which extends laterally downward to the surface of the plateau 28, the intersection of this mound with the plateau being shown by arcuate line 52 in FIG. 1. This raised, medial area intermediate the ends of the shoe is adapted to support the medial longitudinal arch of the foot and further restrains eversion of the foot with respect to the shoe which might otherwise cause dropping of the plantar protuberances of the fifth metatarsal with respect to the rest of the foot and thus unlock the bones of the tarsus.

Rising centrally of the anterior portion of the insert from the plateau 28 is anterior convex mound 42 which is adapted in thickness and position to support the anterior transverse tarsal arch, thereby further restraining movement of the bones of the tarsus and providing additional support for the tarsus at this point. Mound 42 also serves to prevent the foot from sliding rearwardly with respect to the foot. Curved line 54 in FIG. 1 denotes the intersection of mound 42 with the surface of plateau 28.

The heel depression 28, as noted above, tends to anchor the os calcis and restrains movement thereof laterally or medially with respect to the shoe. In concert with the raised, medial area 40 which supports the medial longitudinal arch of the foot, the heel depression 22 additionally restrains eversion of the foot with respect to the shoe. When walking with the foot everted with respect to the shoe, the medial edge of the foot is depressed and the lateral edge of the foot is raised. The weight of the body, acting through the talus, calcaneus and cuboid bones, causes the fifth metatarsal to be depressed with respect to the rest of the foot, thus "unlocking" the bones of the tarsus and causing undue strain on supporting muscles and ligaments. By arresting movement of the os calcis in the heel depression 22, and with the aid of raised, medial area 42, the body weight during a stride is carried first by the os calcis and then by the anterior portion of the first metatarsal, the body weight travelling between these two primary contact areas along the lateral plantar surface of the foot to contact the plantar protuberance of the fifth metatarsal. Thus, during a stride, the tarsus bones are locked as one rises up on the "ball" of one's foot. Trapazoidal shaped protuberance 44 extends anteriorly a sufficient distance to be contacted by the anterior portion of the fifth metatarsal as well, thus insuring that the locking action is maintained throughout a stride. The anterior convex mound 42 cooperates with the above-mentioned contours to further stabilize and balance the foot and to provide a support against which the bones of the tarsus may bear, thus again serving to maintain the locked anterior transverse tarsal arch. As such, the thus-described contoured surface fully balances the foot. The nesting of the os calcis in the depression 22 anchors the os calcis with respect to the shoe and allows the weight of the body to be carried by the os calcis as well as by the tarsal area during walking.

Although described above in the form of an insert, it will be understood that the invention may be formed in the insole itself of a shoe. Although the insert may be formed of a rigid, unyielding material, greatest benefit is found if a resilient material such as a polyurethane or other compressible plastic is employed as the material of the insert of the invention. Inserts of the type described can be molded to fit any shoe size. If desired, the insert of the invention may be produced by bonding together various layers of materials in the manner shown in my U.S. Pat. No. 2,628,440. It is thus to be understood that the foregoing description and the accompanying drawing have been given by way of illustration and example, and not for purposes of limitation, the invention being limited only by the claims which follow.

Claims

I claim:

1. In combination with a shoe, a surface contoured generally to the plantar surface of the foot including a posterior, concave area adapted to receive and support the os calcis and having side walls adapted to restrain the os calcis from lateral or medial movement with respect to the shoe, the anterior wall of the heel depression extending forwardly and upwardly to terminate in a substantially planar elevated, lateral supporting area for supporting the plantar protuberance of the fifth metatarsal.

2. The shoe of claim 1 wherein said surface includes a raised, medial area intermediate the ends of the shoe and adapted to support the medial longitudinal arch of the foot to restrain eversion thereof with respect to the shoe.

3. The shoe of claim 2 wherein said surface includes an anterior convex mound adapted to support the anterior transverse tarsal arch.

4. The shoe of claim 3 wherein, with respect to the curved surface of the shoe sole, the posterior concave surface area is at a first elevation, said raised, medial area intermediate the ends of the shoe and said anterior convex portion adapted to support the anterior transverse tarsal arch are at different, higher elevations, and wherein said raised area for supporting the plantar protuberance of the fifth metatarsal is at an elevation greater than said posterior concave area but less than said anterior, convex area.

5. The shoe of claim 1 wherein the surface is on a structure having a corresponding bottom surface, the bottom surface having a protuberance which in walking supports the distal end of the fifth metatarsus and the phalanges carried thereby.

6. A device for insertion in a shoe and adapted to cooperate therewith in supporting a foot comprising an elongated insert of non-uniform thickness adapted to be disposed of an inner sole of the shoe, said insert having posterior, concave area with side walls adapted to receive and support the os calcis and to restrain the same from lateral or medial movement with respect to the shoe, a raised, medial area intermediate the ends of the shoe and adapted to support the medial longitudinal arch of the foot to restrain eversion of the foot with respect to the shoe, an anterior convex portion positioned to support the anterior, transverse metatarsal arch, and a raised area for supporting the plantar protuberance of the fifth metatarsal, said device permitting that portion of the foot anterior of the cuneiform bones to rest upon the insole of the shoe.

7. The device of claim 6 wherein the device has a bottom surface, the bottom surface having a protuberance which in walking supports the distal end of the fifth metatarsus and the phalanges carried thereby.