Understanding Algor Mortis & Postmortem Changes: A Forensic Guide

Posted on Aug 12, 2024 in Biology

COOLING Cadaveres (Algor Mortis)

Algor mortis, also known as the decrease in body temperature after death, is established in the human body upon death. As the temperature begins to drop, it does so gradually and steadily.

EVOLUTION:

The cadaver is not cooled uniformly around the body with the same speed. Cooling begins in the feet, followed by the hands and face. Rigor mortis can be observed after two hours, starting with the eyelids and the dorsal side of the fingers. It continues to spread to the proximal parts of the limbs, chest, and finally the abdomen, armpits, and neck.

The deep abdominal organs are the last to cool, retaining their temperature for longer. It has even been observed that they may not lose any temperature for up to 24 hours.

Factors that Alter Algor Mortis

Individual Factors:

  • Age: The body of a fetus, newborn, and children cool faster than the bodies of adults.
  • Height and Weight: These factors can influence the overall surface area and thus the rate of cooling.
  • Nutritional Status:
    • Weight: The body of an emaciated person cools faster than the body of a well-nourished person.
    • Nutrition: A malnourished person’s body is cooled more easily than a well-nourished person.
    • Fasting: The body of a fasting person is cooled more quickly than someone who has recently eaten.

PATHOLOGICAL FACTOR OF THE CAUSE OF DEATH

Chronic diseases, death from bleeding, and poisoning accelerate rigor mortis. Cooling is delayed in cadaverous death from acute diseases, infections, death from heat stroke, and sudden death in previously healthy individuals.

ENVIRONMENTAL FACTORS

  • Temperature: The lower the ambient temperature, the faster the cooling of the corpse. The drop in temperature is inversely proportional to the ambient temperature.
  • Ventilation: Greater ventilation leads to a faster drop in body temperature.
  • Humidity: Higher humidity results in faster algor mortis.

Situational Factors

  • Clothing: The more covered the body, the longer it will take for algor mortis to occur. The temperature decrease is inversely proportional to the amount of clothing on the body.

MEDICO LEGAL SIGNIFICANCE OF ALGOR MORTIS

  • Diagnosis of Death: Algor mortis serves as a sign for diagnosing certain death. A body temperature of 20°C is incompatible with life.
  • Estimating Time of Death: While not definitive, the body temperature in the rectal cavity can provide an approximation of the time of death.

EYE SIGNS

  • Loss of Corneal Transparency: A relatively early sign, observable from 45 minutes after death if the eyes were open. If closed, it appears at 24 hours. This results in a slimy film, often called “fish eyes.”
  • Sommer-Larcher Sign: A dark, triangular stain with undefined contours, appearing first on the outside of the eyeballs and later on the inner corner.
  • Hypotonia of the Eyeball: Due to evaporation of intraocular fluid, causing the eyeball to collapse under digital pressure. Appearance depends on whether the eyelids were open or closed.

Livor Mortis (Postmortem Lividity)

Livor mortis is a postmortem sign consisting of wine-red spots on the skin. It’s caused by the settling of blood in dependent areas of the body due to gravity.

Location:

Livor mortis appears in dependent areas, indicating the position of the body after death. It’s not evident in areas of compression, folds, or areas compressed by clothing.

Color:

The color ranges from pink to dark blue, depending on the blood’s condition at the time of death. It’s dark red in mechanical asphyxiation deaths and light red in deaths from hemorrhage.

Stages of Livor Mortis:

  • Appears in the neck within 45 minutes.
  • Appears in the rest of the body within 3 to 5 hours.
  • Fully develops in dependent areas within 12 hours.
  • Once set, the color and shape do not change.
  • The skin on the opposite side of the body is pale.
  • Livor mortis is not present after 24 hours.
  • Livor mortis can change position if the body is moved within 10 to 12 hours after death.
  • New, fainter livor mortis, called paradoxical livor mortis, forms after the body is moved.

Rigor Mortis

Rigor mortis is a postmortem sign characterized by stiffness and hardness of the body, affecting muscle tissue.

Evolution:

  • Starts in smooth muscle (myocardium, diaphragm, sphincters, etc.).
  • Starts in striated muscles 3 to 6 hours after death.
  • Begins in the masseter, orbicularis oculi, face, neck, thorax, abdomen, and finally the limbs.
  • Fully develops within 12 hours when the body is in a supine position.

Characteristics:

  • In athletic individuals, the body takes on a characteristic position due to the prominence of muscles.
  • The hands are slightly adducted with the thumb towards the center, known as the “preacher’s hand.”
  • The jaws are approximated, altering the facial expression.

Three Stages of Rigor Mortis:

  • Setup Phase: Rigidity can be overcome with force, but it will return later.
  • Status Phase: Force can cause fractures and lacerations.
  • Resolution Phase: Reaches maximum intensity at 24 hours, begins to disappear from 36 to 48 hours, following the order in which it appeared.

Factors Altering Rigor Mortis:

  • Nysten’s Law: Early onset rigor mortis is of low intensity and short duration, while delayed onset rigor mortis is intense and long-lasting.
  • Age: In children and the elderly, rigor mortis is early, weak, and short-lived.
  • Fatigue: In cases of death after fatigue, rigor mortis is early, weak, and short-lived.

Cases Where Nysten’s Law Does Not Apply:

  • In deaths from convulsant diseases like tetanus, epilepsy, and strychnine poisoning, rigor mortis is early, lasting, and intense.
  • Temperature: In deaths from heat, rigor mortis is premature, short-lived, and intense. In cold temperatures, rigor mortis is early, intense, and lasting.

MEDICAL LEGAL SIGNIFICANCE of Rigor Mortis

  • Diagnosis of death.
  • Estimation of the time of death.
  • Determination of the body’s position after death.

Cadaveric Spasm

Cadaveric spasm is a postmortem sign where the body retains the last attitude and position it had at the time of death. This is due to the absence of the relaxation phase between flaccidity and rigor mortis.

Etiology:

Causes include death from tetanus, electrocution, certain types of mechanical asphyxiation, intense stress, and intense emotion immediately before death.

Forensic Importance:

Cadaveric spasm can reveal the victim’s final position and attitude, aiding in the reconstruction of events, especially in cases involving weapons.

AUTOPSY

Autopsy means “to see for oneself.” It’s the anatomical, morphological, and pathological examination of a body to determine the cause of death and related manifestations.

TYPES OF AUTOPSY:

  • Clinical Autopsy: Investigates the cause of death and the alterations in tissues and organs due to disease processes.
  • Medico-Legal or Forensic Autopsy: Investigates injuries or abnormalities to help clarify the cause of death in legal cases.

REQUIREMENTS FOR AUTOPSY:

  1. Appropriate facilities (morgue), equipment, instruments, ventilation, and lighting.
  2. Authorization by the medical examiner or coroner.
  3. Proper documentation and chain of custody.
  4. A qualified forensic pathologist.

MEDICO LEGAL AUTOPSY RULES:

  1. Focus on injuries and disorders that could have caused death.
  2. Use linear skin incisions that can be sutured properly, respecting the body’s appearance.
  3. Perform a complete autopsy, including the spine.
  4. Open the cranial, thoracic, and abdominal cavities.
  5. Take samples for histological and toxicological tests.
  6. Document all findings in writing.
  7. Submit the autopsy report to the coroner within 24 hours.

SIGNS RELATED TO THE CESSATION OF CARDIOCIRCULATORY FUNCTION:

  • Bouchut Sign: Absence of heart sounds during auscultation for 15-20 minutes.
  • Magnus Sign: Absence of discoloration when compressing a limb or finger.
  • Transillumination: Absence of pink coloration when shining a light in the mouth or under the hand.
  • Forcipressure: Disappearance of the imprint after pinching the skin with tweezers.
  • Electrocardiogram (ECG): Shows an isoelectric line, indicating no cardiac activity.

RESPIRATORY SIGNS:

  • Mirror Test: No fogging of a mirror placed in front of the nostrils or mouth.
  • Feather Test: No movement of a feather placed near the nostrils or mouth.
  • Flame Test: No flickering of a flame placed near the nostrils or mouth.
  • Glass of Water Test: No oscillations in the water level when a glass of water is placed on the epigastrium.
  • Laet Test: Demonstrates acidification in the body using a reagent.
  • Auscultation of the Chest: Absence of breath sounds.

NEUROLOGICAL SIGNS:

  • Immobility of the body.
  • Muscle flaccidity.
  • Loss of sensation.
  • Paralysis of sphincters.
  • Jodi Sign: Change in pupil shape from circular to elliptical or oval when the eyeball is pressed.

REQUIREMENTS FOR REMOVAL OF THE CORPSE:

  • Authorization by the coroner or medical examiner.
  • Notification by the investigating agency.
  • Presence at the scene where the body is located.
  • Examination of the corpse.
  • Necessary materials and equipment.

INDICATIONS FOR REMOVAL OF THE CORPSE:

  1. Violent death.
  2. Sudden death.
  3. Homicide.
  4. Death by poisoning.
  5. Infanticide.
  6. Death by abortion.
  7. Death in judicial detention or prison.
  8. Death potentially related to medical malpractice.
  9. Exhumations.

PROCEDURES FOR REMOVAL OF THE CORPSE:

  • Identify the body.
  • Record the name (full, clear, and legible).
  • Record the date of birth and age.
  • Collect identification documents.
  • Record the date and time of removal.
  • Record the site of removal and the place of death.
  • Estimate the date and time of death using available evidence.
  • Describe clothing and personal items, noting stains, fingerprints, bleeding, etc.
  • Describe the position and orientation of the body.
  • Describe any injuries, including their nature, location, shape, number, size, direction, and characteristics.
  • Document the background information.
  • Record the name of the coroner or medical examiner.
  • Issue the death certificate.

DESTRUCTIVE PROCESSES OF CADAVERES

PUTREFACTION:

Putrefaction is a transformative, destructive, postmortem sign characterized by the decomposition of organic matter, particularly proteins, with the production of fermentation gases.

Evolution:

It begins after rigor mortis, typically 24-36 hours after death. Aerobic bacteria in the digestive tract are the first to act, followed by anaerobic bacteria as oxygen is depleted. This leads to the breakdown of complex substances, releasing gases like hydrogen sulfide. The body eventually decomposes, leaving behind bones, teeth, hair, nails, and other calcareous components.

Stages of Putrefaction:

  • Coloration Phase: Characterized by a green discoloration that starts in the right iliac fossa and spreads throughout the body. This is due to the oxidation of hemoglobin.
  • Emphysematous or Gas Phase: Marked by the production of gases that cause bloating and distension of the body.
  • Liquefaction Phase: Tissues liquefy, leading to the formation of blisters and the detachment of appendages like nails and hair.
  • Skeletonization Phase: Soft tissues decompose, leaving behind the skeletal remains.

Factors Affecting Putrefaction:

  • Individual Conditions: Age, constitution, and overall health.
  • Environmental Conditions: Aeration, temperature, and humidity.

SAPONIFICATION (Adipocere Formation):

Saponification is a transformative, conservative, postmortem sign characterized by the formation of a waxy, soapy substance in the body. It’s due to the decomposition of body fat into glycerol and fatty acids.

Types of Saponification:

  • Recent Saponification: Soft and greasy, allowing for molding and recognition of underlying tissues.
  • Old Saponification: Hard, dry, and brittle.

Forensic Importance of Saponification:

  • Can reveal injuries that occurred before death, even if they’re obscured by the saponified layer.
  • Can aid in the identification of the body.

MUMMIFICATION:

Mummification is a process of drying and preservation of the body due to dehydration. It can occur naturally or be induced artificially.

Requirements for Natural Mummification:

  • High temperature.
  • Low humidity.
  • Good ventilation.

Individual Factors Affecting Mummification:

  • Age: More common in children.
  • Constitution: More common in asthenic individuals.
  • Sex: More common in women.
  • Cause of Death: More common in deaths from severe bleeding or dehydration.

Forensic Importance of Mummification:

  • Identification of the body.
  • Determination of the cause of death.
  • Estimation of the time of death.

TYPES OF DEATH

Apparent Death:

A state where vital functions are severely attenuated, giving the appearance of death. It’s characterized by loss of consciousness, neuromuscular immobility, and the apparent absence of heartbeat, pulse, and breathing.

Clinical Death:

The cessation of cardiovascular, respiratory, and neurological functions, but with the possibility of revival through resuscitation efforts.

Intermediate Death:

The gradual extinction of biological activities, where resuscitation is no longer possible. An example is brain death with a persistent vegetative state.

Absolute or Real Death:

The complete and irreversible cessation of all vital functions.

Sudden Death:

Unexpected death from a non-violent cause in a person who appeared healthy or whose illness did not suggest an immediate fatal outcome.

Violent Death:

Death from external causes, such as mechanical, physical, or chemical trauma, with rapid effects.

Legal Death:

Death that is officially certified and documented.

Agony:

The period between the onset of dying and death. It’s characterized by a decline in mental function and can have legal implications, such as the validity of wills or powers of attorney.

Rights of the Dying Patient:

  1. To receive competent and ethical medical care.
  2. To be treated with respect and compassion by healthcare providers.