What is Rigor Mortis?
Today, we’re going to go over briefly rigor mortis and liver mortis. We’re going to talk about what they are, how they’re caused, and by when they usually expire or reach an end. When we think about rigor mortis, we’re talking about body rigidity, how the body goes rigid shortly after death.
It’s caused by a conversion of glycogen stores in the body into lactic acid. The glycogen is turned into lactic acid and the muscles in the body get rigid. Now, the muscles themselves are not shortened in any way, but the body does get rigid because of this conversion of glycogen into lactic acid.
Things like heat, acidosis, uremia, or other conditions that lower the pH of the body accelerate rigor mortis. Rigor usually dissipates within 12 to 36 hours after death. That’s rigor mortis, the rigidity of the body from the conversion of like glycogen into lactic acid.
Liver mortis is different. Liver mortis is the pooling of the blood in the dependent areas of the body in the lowest part of the body. Here, the blood comes and pools in the capillary beds and causes them to expand.
The areas where this is happening usually turn purple or dark blue. Maximum settling of the blood in these dependent areas, in the lowest part of the body, the liver mortis, is usually 8 to 12 hours after death. It is completed at that point.
Things to remember then under rigor: That it’s caused by the conversion of glycogen into lactic acid, things that lower the pH of the body accelerate it, it’s usually completely dissipated 12 to 36 hours after death.
With liver mortis, it’s the pooling of the blood in dependent areas of the body, the lowest part of the body, capillary beds expand, the color is purple or dark blue, and maximum settling of the blood usually occurs within 8 to 12 hours after death.