The conception of the synovial membrane as an endothelium or epithelium designed to secrete the synovial fluid was challenged by Hueter1 in 1866. By the method of silver impregnation he demonstrated interspaces between the synovial cells filled by collagenous fibers which, in some places, covered the upper surface of the membrane. After thirty years of controversy, Hueter's views were brought to general rocognition by Braun2 and Hammer.3 The majority of recent investigators regard the synovial membrane as a modified connective tissue. This theory, however, makes the origin of the synovial fluid problematical. Of the various explanations advanced, none is supported by sufficient evidence.
This study deals with the phenomena of precipitation, the viscosity, the specific gravity and the mucinous substance of synovial fluids. Different fractions were separated and analyzed. By correlation of the data, an effort was made to determine the source and composition of the synovial
KLING DH. THE NATURE AND ORIGIN OF SYNOVIAL FLUID. Arch Surg. 1931;23(4):543-570. doi:10.1001/archsurg.1931.01160100002001