This review examines a number of theoretical constitutive equations which are applicable to the description of rheological behaviors of synovial fluids. These equations include the integral type, the rate type, the differential type and the generalized new-tonian fluid. Explicit values of the material parameters and/or material functions appearing in these equations are obtained from the many rheological measurements on synovial fluids of the literature. Many of the values of these parameters are taken from the literature, but some are newly computed values obtained by the present authors to make the list of available constitutive equations more extensive, using the existing experimental data. It is hoped that the diversity of the constitutive equations presented here and their appropriate material constants and/or functions will afford researchers in the field of synovial joint biomechanics the choice of a particular constitutive model for synovial fluid to meet their specific purpose.