Surface structure of articular cartilage Historical review

In the previous paper it has been shown that the surfaces of articular cartilage in living mammals and birds are not smooth but are covered by a series of secondary irregularities and of 20 to 30 [km. tertiary undulations, both superimposed on the broad prim-ary anatomical contours (Gardner and McGillivray, 1971). The experiments from which this evidence has been derived have drawn attention to a historical paradox: the conspicuous smoothness of articular cartilage, emphasized by William Hunter (1742-43), is evident grossly. Yet the scanning electron micro-scope quickly revealed that articular cartilage sur-faces are irregular and that the surface irregularities are sufficiently large to be easily seen with a primitive compound microscope. Cartilage surfaces have bee