The document presents a dynamic model of an anthropomorphic robotics finger mechanism (ARFM) based on the biological equivalent of the human hand. Each finger link interconnects at joints equivalent to the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints in the human hand. The Lagrangian method is used to derive the dynamics of the proposed mathematical model. Equations are developed to determine the torque at each joint of the ARFM based on the kinetic and potential energy of each link. The dynamic modeling presented enables subsequent simulation of the ARFM design.