Bidirectional biomechanical prosthetic full finger configured for abduction and adduction with MCP pivot

A bidirectional biomechanically driven prosthetic finger, comprising:

• a metacarpophalangeal (MCP) pivot for attachment to a hand of a user, the MCP pivot having an articulation joint configured to rotate the MCP pivot relative to the hand within a plane parallel to an x-y plane and about an axis parallel to a z axis;
• a distal coupler;
• an articulation assembly hingedly coupled between the MCP pivot and the distal coupler, the articulation assembly configured to articulate relative to the hand within a plane parallel to an x-z plane and about one or more axes parallel to a y axis, the articulation assembly comprising:
• a proximal coupler rotatively coupled with the distal coupler via a first hinged connection;
• an adjustable ring tendon having a proximal end, a distal end, and a ring disposed thereon, wherein:
• the ring is configured to anchor onto a residual finger of the user;
• the ring is slidably adjustable between the proximal and distal ends of the adjustable ring tendon;
• the adjustable ring tendon is rotatively coupled with the proximal coupler via a third hinged connection;
• and
• the first and third hinged connections define a midline relative to the z axis;
• and
• a distal rocker extending between the distal coupler and the adjustable ring tendon, the distal rocker having a distal end and a proximal end, the distal end of the distal rocker rotatively coupling with the distal coupler via a second hinged connection located below the midline, the proximal end of the distal rocker rotatively coupling with the adjustable ring tendon via a fourth hinged connection located above the midline.

A method of biomechanically operating a bidirectional prosthetic finger assembly including a hand strap, a metacarpophalangeal (MCP) pivot affixed to the hand strap, a distal coupler, and an adjustable articulation assembly rotatively coupled between the MCP pivot and the distal coupler, the adjustable articulation assembly including a ring configured to receive a residual finger of a user's hand, comprising:

• assessing a length of the residual finger;
• adjusting the ring to a target location along the adjustable articulation assembly, the target location based on the length of the residual finger;
• securing the ring at the target location;
• sliding the prosthetic finger assembly onto the residual finger such that the ring encircles the residual finger adjacent to the target location and the MCP pivot aligns with an MCP joint of the user;
• securing the hand strap about the hand;
• moving the residual finger vertically within the ring, thereby causing the adjustable articulation assembly together with the distal coupler to articulate within a plane parallel to an x-z plane and about one or more axes parallel to a y axis in a manner that emulates a finger's natural articulation;
• and
• moving the residual finger laterally within the ring, thereby causing the MCP pivot to rotate about an axis parallel to a z axis within a plane parallel to an x-y plane, such that the articulation assembly together with the distal coupler abduct away from a midline of the hand and adduct toward the midline of the hand;
• wherein the adjustable articulation assembly comprises:
• a proximal coupler rotatively coupled with the distal coupler via a first hinged connection;
• an adjustable ring tendon having a longitudinal adjustment mechanism with a proximal end and a distal end, the target location disposed therebetween, wherein:
• the adjustable ring tendon is rotatively coupled with the proximal coupler via a third hinged connection;
• and
• the first and third hinged connections define a midline relative to a z axis;
• and
• a distal rocker extending between the distal coupler and the adjustable ring tendon, the distal rocker having a distal end and a proximal end, the distal end of the distal rocker rotatively coupling with the distal coupler via a second hinged connection located below the midline, the proximal end of the distal rocker rotatively coupling with the adjustable ring tendon via a fourth hinged connection located above the midline.