What is the term for the body stiffening that occurs after death?

Rigor mortis refers to the process of stiffness that develops in skeletal muscles after death due to chemical changes in the muscle tissue. Shortly after the heart stops beating, the body undergoes a series of physiological changes, including the depletion of ATP (adenosine triphosphate), which is crucial for muscle relaxation. As ATP levels fall, the muscles become rigid because they can no longer relax after contracting. This rigidity typically begins a few hours after death, peaks around 12 hours, and gradually diminishes after 24 to 36 hours.

Understanding rigor mortis is key in various fields such as forensic science, as it can help estimate the time of death and assist in investigations. Other terms in the list refer to different post-mortem processes: algor mortis relates to the cooling of the body, livor mortis involves the pooling of blood after death, and decomposition refers to the breakdown of the body tissues over time. Therefore, rigor mortis is specifically the term associated with muscular stiffness following death.