Structural connections of the muscle‐tendon junction

Abstract

The muscle‐tendon junction of murine skeletal muscles has been analyzed by a variety of extraction techniques, by myosin subfragment‐1 binding experiments, and by ultrastructural immunocytochemistry. The results indicate that the muscle‐tendon junction is composed of four distinct domains: an intracellular domain, the internal lamina; a domain connecting the internal lamina with the lamina densa of the external lamina, the connecting domain; the lamina densa; and a domain which attaches the lamina densa to the collagen fibers, the matrix. Each of these domains is distinct with respect to position, three‐dimensional organization, and molecular composition, and is therefore considered to have a unique role in the transmission of contractile force.