Prosthetic Components By Jan J Stokosa, CP, American Prosthetics Institute, Ltd Reviewed / Revised Jan 2021 | Modified Sep 2022 View Patient Education A limb prosthesis has 3 main parts: Interface Structural components Cover Interface between the residual limb and prosthesis The prosthesis attaches to the body by direct skin contact or by an interface made of various thin viscoelastic cushion materials worn over the residual limb.