What defines a postmortem physical change?

A postmortem physical change refers to alterations that occur in the body after death, specifically changes in form or state without affecting the underlying chemical composition. Such changes can include processes like cooling of the body (algor mortis), rigor mortis (stiffening of muscles), and livor mortis (settling of blood). These alterations affect the physiological state of the body and can be observed and measured but do not entail a transformation at the molecular level, which would involve a change in chemical composition.

While changes in chemical composition and temperature are significant in the context of decomposition and postmortem processes, they do not fall under the definition of a physical change. Physical changes maintain the original substance's composition, which is critical in distinguishing them from chemical changes that fundamentally alter the substance itself. Therefore, the definition of a postmortem physical change focuses specifically on those transformations in the state or appearance rather than any fundamental chemical reactions or temperature fluctuations.