The myofibrillar M-band in the cryo-section—analysis of section thickness

Information regarding the formation and the thickness of cryo-sections is of importance for an adequate interpretation of cryo-sectioned biological material. In this study we have taken advantage of the regular arrangement of filaments in myofibrils in an analysis of these matters. It is concluded that the sections are formed partly by fracturing in a way similar to that visualized in replicas made by the freeze-fracturing and -etching procedure.