Experimental analysis of the cause of downward progression of rigor mortis

尸僵通常向下发展，但原因尚不清楚。我们发现肌纤维类型的比例影响尸僵的进展，认为肌肉间比例的差异是尸僵向下进展的原因之一。本文用ATP酶组织化学方法测定了几种大鼠肌肉的肌纤维类型比例，用~ 1H-P-核磁共振方法测定了死后肌肉磷酸盐的变化<31>。磷酸肌酸和ATP在红色肌肉中比在白色肌肉中下降更快。还测量了死后僵硬度和僵硬张力的变化。在红色肌肉中它们比在白色肌肉中增加得更快。因此，我们证实了红肌的尸僵比白色肌的尸僵进展更快，温度对时间进程的影响更大，我们认为肌纤维类型比例和温度对尸僵的影响是导致人尸体尸僵中尸僵向下进展的原因。

Rigor mortis usually progresses downwards, but the cause is not known. We found that proportion of muscle fiber type affected progression of rigor mortis, and thought that the difference in the proportion between muscles is one of the causes of downward progression of rigor mortis.We use liquid paraffin to make a circumstance around muscles in dead bodies. Proportions of muscle fiber types in several kinds of rat muscles were measured with ATPase enzyme histochemistry.Postmortem changes in phosphates in the muscles were measured with ^<31>P-nuclear magnetic resonance. Creatine phosphate and ATP decreased more rapidly in red muscles than in white muscles. Postmortem changes in stiffness and rigor tension were also measured. They increased more rapidly in red muscles than in white muscles. The changes were affected by temperature.Therefore, we confirmed that rigor mortis of red muscles progressed more rapidly than that of white muscles, and that temperature affected the time course much.We thought that the effects of proportion of muscle fiber types and temperature on rigor mortis were causes of downward progression of rigor mortis in rigor mortis in human cadavers.