Abstract: An improved biomechanical ankle is provided which imitates the three primary categories of movement in a human foot. Parallel sole and limb supporting plates are held in spaced relationship by an upright post. The limb supporting plate is connected to the post with a ball and socket joint. A helical spring is fixed between the plates to provide resilient support to the anterior portion of the foot in imitation of normal muscular control. The ball and socket joint, in cooperation with the spring, permits the biomechanical ankle to imitate the inversion-eversion, plantar flexion-dorsiflexion, and lateral rotation found in a normal human foot.

Abstract: The present invention provides a biomechanical ankle prosthesis device comprising a main base plate member adapted for connection to an artificial foot; a connector hinge member having an extended portion pivotally connected to one end of the main base plate member so as to pivot relative thereto about the longitudinal axis of the main base plate member, the connector hinge member being further defined as comprising a hinged portion having a longitudinal axis transverse to that of the main base plate member; a leg attachment member having a top portion adapted for connection to a user and its bottom portion being provided with a hinge portion operably connected to the connector hinge member to allow the leg attachment member and the main base plate member to move relative to each other in essentially the same plane about the longitudinal axis of the hinge assembly defined between the connector hinge member and the leg attachment member; and a spring interposed between the leg attachment member and the main ba