What is the correct term for muscle stiffness that occurs after death?

The term “rigor mortis” refers specifically to the physiological process of muscle stiffening that occurs after death. This process is a result of biochemical changes that happen in the muscle tissues following the cessation of life. After death, the body experiences a depletion of adenosine triphosphate (ATP), which is essential for muscle relaxation. As ATP levels fall, actin and myosin filaments in muscle fibers become locked together, resulting in stiffness. Rigor mortis typically begins within a few hours after death and can last for several days, depending on environmental conditions.

While "cadaveric rigidity," "post-mortem stiffness," and "muscle rigidity" might describe similar phenomena, they are not the specific scientific terms used to denote this precise post-mortem condition. "Cadaveric rigidity" is often used interchangeably with rigor mortis but is less commonly recognized in medical terminology as the definitive term. The other alternatives lack the specific connotation and established recognition that rigor mortis carries in both medical and forensic contexts.