Relative importance of various tissues in joint stiffness

Abstract

The rheological properties of the cat”s wrist were found to be similar to those of the human metacarpophalangeal joint. In the intact joint nonlinear elasticity and plasticity accounted for most of the stiffness, elasticity being twice as great as plasticity. Inertia accounted for <6% of the total torque, and viscosity <2%. Frictional torques were immeasurably small, being <0.1% of the total. The joint capsule contributed 47%, passive motion of the muscles 41%, the tendons 10%, and the skin 2% to the total torque required to move the joint in its midrange. Toward the extremes of joint motion the restraining effect of tendons became more important. Submitted on February 8, 1962