Abstract: An article of footwear and insert for an article of footwear are provided with means for stimulating cutaneous pressure sensation from the perimeter of the plantar surface (sole) of the foot. Increasing cutaneous sensation from the perimeter of the plantar foot surface provides the central nervous system of the wearer of the footwear with an increased ability to detect and react to shifts of the body's center of gravity toward the edges of the feet which, if left uncorrected, could result in a loss of balance or a fall. An insole is disclosed which is provided with an elongate member or a series of protrusions which form a narrow ridge in close proximity to the perimeter of the insole, the ridge being adapted to protrude upwardly against the plantar foot surface along at least a portion of the perimeter thereof.

Abstract: An artificial disc for a human spine. The disc has upper and lower members hinged together at their rear portions and biased apart at their fronts by stiff coil springs. Rear stop surfaces limit the opening movement of the members. Vertically projecting tabs at the front and side of each member are rigidly screwed to the adjacent vertebrae. Tolerances in the hinge allow limited side to side rocking. The disc and screws are made of titanium alloy or cobalt chrome alloy. In a modified version a hinge pin is replaced by cables tying the members together.