Muscle Changes After Death

Rigor mortis

General muscle flaccidity

RM (rigor mortis)

Rigor mortis is the stiffening of muscles after death due to the breakdown of ATP. It develops in the body within 4-12 hours after death, starting with smaller muscle groups and progressing to larger ones.

Environmental temperature is the most important factor. Other factors include the individual's body mass, physical activity before death, and diseases causing elevated body temperature.

Rigor mortis can help estimate the time of death and determine if the body was moved after rigor mortis had developed.

Rigor mortis is the stiffening of muscles after death, while cadaveric spasm is a much more intense and rare form of rigidity/stiffness in the body.

Cadaveric spasm is a phenomenon where the muscles in the body remain in a tense state immediately after death and persist into the period of rigor mortis. It is identified when an object is clenched tightly in the hand and cannot be released through muscle manipulation.

Cadaveric spasm has been documented in cases of suicide where the weapon is tightly grasped in the hand, homicides where objects like buttons or hair are found clenched in the hand, drowning and mountain accidents where stones or branches are held tightly, and car, airplane, and train accidents where victims are found gripping objects like steering wheels or cell phones.

When cadaveric spasm is identified in a body, it provides important information about the circumstances under which a person died. For example, if a victim is thought to have committed suicide and the weapon is tightly held in their hand, it can be taken as sufficient proof of suicide.

Cadaveric spasm disappears when the full effect of decomposition sets in, which usually occurs after approximately 48 hours. This is because rigor mortis, including cadaveric spasm, is a temporary state that occurs before decomposition progresses.