Rigor Mortis and Putrefaction: Stages, Factors, and Medicolegal Significance
Rigor Mortis: Stages and Factors
After death, rigor mortis begins, initially affecting the muscles of the jaw and eyelid, then spreading to the face and neck, subsequently invading the chest, arms, trunk, and finally the legs. In cadavers placed in a dependent position, the stiffness progresses in an ascending order. Rigor mortis is usually complete within 8 to 12 hours, reaching maximum intensity at 24 hours, and disappearing at 36 or 48 hours.
There are exceptions, including early rigidities that complete within 3 hours and late rigidities that begin more than 7 hours after death.
Overcoming Rigor Mortis
The process of rigor mortis can be divided into three phases:
- Implementation Phase: This phase starts with the onset of stiffness until it reaches its maximum intensity (between 3 and 24 hours post mortem). During this period, the rigidity can be overcome by applying some force, causing the member to regain its flaccidity, but the process restarts after a while, returning the muscles to a rigid state.
- State Period: The stiffness is almost unbeatable without causing tears or fractures.
- Resolving Stiffness: (From 36 hours postmortem) Muscle strength expires, and muscle mass does not return to the rigid state.
Circumstances Modifying Rigor Mortis
Rigor mortis depends on the condition or integrity of the musculature at the time of death. When stiffness starts early, the intensity is low and of limited duration. Conversely, when the start is delayed, the intensity is remarkable and the duration prolonged.
Individual circumstances, environmental conditions, and circumstances regarding the cause of death can modify the evolution of cadaveric stiffness. These can be divided into two groups:
- Those that follow Nysten’s Law, maintaining the dependence between the time of onset, intensity, and duration of rigidity.
- Those that separate from Nysten’s Law.
Medicolegal Importance of Rigor Mortis
Rigor mortis is important in the following cases:
- Diagnosis of real death.
- Determination of time of death.
- Reconstruction of the circumstances in which death occurred, such as diagnosing the simulation of suicide by gunshot.
Putrefaction: Stages and Factors
Evolution of Putrefaction
Putrefaction evolves in the body through four phases:
- Chromatic Period: Starts with the green spot, located initially in the right iliac fossa, but then spreads throughout the body, becoming darker and acquiring a blackish-brown tone. This period usually begins 24 hours after death, lasting several days.
- Emphysematous Period: Characterized by the development of a large amount of gas, ballooning and disfiguring all parts of the body. Gas injection pervades subcutaneous tissue. This period lasts several days, sometimes even a couple of weeks.
- Colliquative Period: Characterized by liquefaction. The epidermis separates from the dermis, forming blisters of variable size, filled with brownish sanious fluid. Liquefaction is established. Gases escape, and the body loses the macrosomic appearance it had in the previous liquefaction stage. This period lasts several months, generally from 8 to 10.
- Skeletal Reduction Period: For a period ranging from 2 to 3 years up to 5, all soft parts of the corpse disappear through liquefaction and processing into putrilage. The elements that are often more resistant are fibrous tissue, ligaments, and cartilage, so the skeleton stays together throughout this period, but ultimately these items also decompose.
Conditions Modifying Putrefaction
Putrefaction is modified by terms dependent on each other in the same subject and the environment.
Individual Factors
Influences