Fine structure changes of human skeletal muscle were studied by mechanical injury. In the zone of the primary point of impact complete disruption of the muscle cells could be noticed. The degree of disorganization of the contractile elements was so extreme that the I and A bands and the H zone were homogenized, and only the Z line could be identified. In the zone around the point of impact, muscle fibers with ruptured filaments, disintegration of sarcomeres, and hypercontration were found in the early period. About 2 hours after the injury the myofilamental alterations reached a peak, and no progression of the damage could be demonstrated later. In the late period the alterations of mitochondria, sarcoplasmic reticulum, and cell nuclei were dominant versus the myofibrillar changes. In the macroscopically uninjured region of the muscle, intact muscle fibers as well as muscle fibers with hype rcontraction, ruptured filaments, zig-zag formed Z lines were found. In the author's opinion the myofilamental changes were caused by the direct traumatic effect and/or by the hyper contraction. Damage of the other cell structures developed only later, based on other mechanisms (e.g., hypoxia, circulatory demages, hemorrhage).
- Fine structural changes
- Muscle injury
ASJC Scopus subject areas
- Pathology and Forensic Medicine