A component of an external lower limb prosthesis [hip, knee, or ankle-foot prosthesis] designed as: 1) a structural element to connect and maintain the structural integrity between the components of the prosthesis [e.g., between a socket and a knee joint prosthesis]; and/or 2) an alignment element to enable adjustment of the orientation of the prosthesis components relative to each other and to the patient (e.g., mediolateral shift, anteroposterior tilt). It may be in the form of a tube, pylon, adaptor, attachment block, clamp, pyramid, socket anchor, plate, or other design, and is intended to remain an integral part of the fitted prosthesis.