Light microscopical investigations on structural changes of skeletal muscle as artifacts after postmortem stimulation

Samples of skeletal muscle were taken from 20 human corpses where mechanical or electrical stimulation had been carried out up to 8h postmortem (hpm) in order to estimate the time since death. The stimulation had caused an idiomuscular bulge or tetanic contraction of the muscle tissue at this location. The muscle samples were examined for structural changes of the fibers by light microscopy. A comparison with control muscle samples taken contralaterally from the same corpse, showed that the findings previously interpreted as being of intravital origin, e.g. destruction of fiber integrity, invagination and contraction bands, could also be due to postmortem alterations. It is hypothesized that structural changes to the muscle fibers can, in general, be produced as long as the manifestation time is shorter than the supravital phase after the time of force impact.