US Patent 7727285 Prosthetic foot with variable medial/lateral stiffness

A prosthetic foot includes an elongated foot member, extending between a toe section positioned at a toe location of a natural foot and a heel section positioned at a heel location of a natural foot. The elongated foot member also extends through an elevated arch section positioned between the toe section and heel section at an approximate arch location of a natural foot. An arch block is disposed below the elongated foot member under the elevated arch section. The arch block is sized and shaped to substantially fill a space or volume under the arch section. The arch block has geometric and physical properties that facilitate medial to lateral rotation to the prosthetic foot.