What is the term for the stiffness of the body that sets in several hours after death?

The term that describes the stiffness of the body occurring several hours after death is rigor mortis. This physiological process involves the biochemical changes in muscle tissues that lead to the stiffening of muscles due to the depletion of adenosine triphosphate (ATP), which is necessary for muscle relaxation. After death, the body undergoes a series of changes, and rigor mortis typically begins within 2-6 hours post-mortem, reaching its peak stiffness around 12 hours, and then gradually dissipating over the next couple of days. This phenomenon plays a significant role in forensic science, as the timing of rigor mortis can help determine the time of death in an investigation.

The other terms refer to different post-mortem processes. Algor mortis describes the cooling of the body after death, while cadaveric spasm refers to an instantaneous type of rigor mortis occurring at the time of death or in rare cases during extreme situations. Post-mortem rigidity is simply another way to reference rigor mortis but is less commonly used. Therefore, rigor mortis is the most precise and widely recognized term for the stiffness that develops in dead bodies.