[Ultrastructural changes of human skeletal muscle after tendon and nerve injuries. I. Fine-structural changes of the hand muscles after tendor injuries (author's transl)].

During reconstructive procedures performed 4--16 weeks after the tendon lesion the specimens obtained from the injured muscle have been examined by the authors. It was found that after the tendon injury inactivity atrophy develops and a condition of equilibrum could be observed at this time. The most important changes in the fine structure were seen in the contractile elements: there were atrophied, homogenized, fragmentated and ragged independently from the functional unities. The number of the mitochondria was considerably decreased, the sarcoplasmatic reticulum was increased, and the difference between the originally red and white muscular fibres was indistinct. The glycogen content of the musculature was decreased, or it disappeared completely. No pathological changes have been observed in the sarcolemme, the cell nuclei and the motor nerve end-plates.