What is rigor mortis?

• A. Will be destroyed by embalming
• B. Cooling of the body
• C. Stiffening of the muscles after death
• D. Pooling of blood

Answer: (C)

Rigor mortis is the stiffening of the muscles after death. When the body stops functioning, cells run out of energy (ATP) and can no longer detach the myosin heads from actin in muscle fibers. That blockage causes muscles to lock in place, leading to a rigid, fixed posture. This stiffness usually begins a few hours after death, peaks around about a half-day to a day, and then gradually dissipates as proteins break down during decomposition. It’s different from livor mortis, the pooling of blood that creates discoloration on the body, and from algor mortis, the cooling of the body. Embalming can preserve or alter the appearance but doesn’t cause or reverse rigor mortis itself.