What term is used to describe the sign of muscle stiffening after death?

The term that describes the sign of muscle stiffening after death is rigor mortis. Rigor mortis is a postmortem change that occurs as biochemical processes cease and the muscles become rigid due to changes in muscle proteins. After death, the body undergoes a series of changes, and rigor mortis typically begins within a few hours, peaks around 12 hours, and then gradually dissipates after about 24 to 36 hours.

Understanding rigor mortis is critical in the context of a crime scene investigation, as it can help forensic experts determine the time of death. The onset and duration of rigor mortis can provide valuable information when assessing the circumstances surrounding a death.

The other terms mentioned are related but describe different phenomena associated with postmortem changes. Cadaveric spasm, for example, refers to a sudden stiffening of the muscles at the time of death, often associated with violent deaths, but is not the same as the general stiffening seen with rigor mortis. Livor mortis, on the other hand, involves the pooling of blood in the lower parts of the body due to gravity after the heart has stopped, and autolysis pertains to the breakdown of cells and tissues that occurs postmortem. Thus, rigor