Which factor is not listed as affecting onset, duration, and passing of rigor mortis?

Which factor is not listed as affecting onset, duration, and passing of rigor mortis?

• A. Ambient temperature
• B. Cause and manner of death
• C. Eye color
• D. Condition of muscles

Answer: (C)

Rigor mortis arises from biochemical changes in muscles after death, driven by the depletion of ATP and the continued cross-bridging of actin and myosin when calcium remains in the muscle cells. Factors that alter the rate of these processes will change when rigor appears, how long it lasts, and when it passes. Ambient temperature changes the speed of chemical reactions in the body after death. Higher temperatures accelerate these reactions, so rigor can set in sooner and may pass sooner as proteolysis progresses. Lower temperatures slow things down, delaying onset and often prolonging the stiff phase. The cause and manner of death influence the metabolic state at the moment of death, which in turn affects how quickly ATP is depleted and how the muscle environment shifts postmortem. This can alter both the timing of rigor and its duration. The condition of the muscles before death—such as conditioning, prior exertion, or injury—also matters because it affects energy stores and how readily the muscles respond to the postmortem biochemistry that drives rigor. Eye color, on the other hand, has no effect on these muscle biochemistry processes after death. It is not related to ATP depletion or cross-bridge formation, so it is not listed as a factor influencing onset, duration, or passing of rigor mortis.

Rigor mortis arises from biochemical changes in muscles after death, driven by the depletion of ATP and the continued cross-bridging of actin and myosin when calcium remains in the muscle cells. Factors that alter the rate of these processes will change when rigor appears, how long it lasts, and when it passes.

Ambient temperature changes the speed of chemical reactions in the body after death. Higher temperatures accelerate these reactions, so rigor can set in sooner and may pass sooner as proteolysis progresses. Lower temperatures slow things down, delaying onset and often prolonging the stiff phase.

The cause and manner of death influence the metabolic state at the moment of death, which in turn affects how quickly ATP is depleted and how the muscle environment shifts postmortem. This can alter both the timing of rigor and its duration.

The condition of the muscles before death—such as conditioning, prior exertion, or injury—also matters because it affects energy stores and how readily the muscles respond to the postmortem biochemistry that drives rigor.

Eye color, on the other hand, has no effect on these muscle biochemistry processes after death. It is not related to ATP depletion or cross-bridge formation, so it is not listed as a factor influencing onset, duration, or passing of rigor mortis.