Understanding Muscle Pathology

Abstract

Human skeletal muscle is divided and subdivided into smaller muscular components. The gross muscle is composed of multiple fasciculi; these are in turn divided into the muscle fibers, which are subdivided into myofibrils and, finally, into myofilaments. The longitudinal and cross-sectional appearance of the muscle fibers can be identified with the light microscope (Figure 1.1 A). The electron microscope identifies the myofibril and the various components of the two membrane-limiting networks surrounding the myofibril, i.e., the sarcoplasmic reticulum and the T system. The electron microscope further identifies various bands and lines seen on the surface of the myofibril (Figures 1.1 to 1.3).