Underactuated robotic hands are becoming popular in complex robotic designs where mass and size are yet limited. Such designs require a tradeoff between versatility and simplicity. This is the case for prosthetic robotic hands, which need to imitate the human hand both in functionality and dimensions as closely as possible to achieve a natural feeling solution for the patient. This paper presents the initial mechanical analysis of the design of an anthropomorphic hand with 15 degrees of freedom using six electric motor actuators. A transmission system of cables and pulleys is used as the underactuated mechanism in order to propagate the motor torque over the three joints of each finger, and springs are used to provide the passive return actuation. The design has been validated according to its ability to stably grasp different cylindrical objects. The stability of the grasp has been judged according to the criterion of positive or zero contact forces being present at all points of contact between the hand and the object in a static case. A simulation of the grasping procedure where the contact forces aremodeled over time has been developed in Matlab (R). It has been shown that the design process requires iterative steps, as multiple factors such as spring stiffness, pulley radii, and motor torques will affect the stability of grasping of the hand and its effectiveness as a prosthetic device.