FSC100 Chapter 6 Notes
CHAPTER 6: SUDDEN AND NOT - SO SUDDEN DEATH:
Defining Death:
Death is not a singular event; it's a continuous process.
The length of the death process depends on the body's condition and the environment.
Somatic death is the first stage, marked by the cessation of cardiac activity, respiration, reflexes, and brain activity.
Muscles, organs, tissues, and cells start breaking down and dying at varying intervals (3 minutes to a few hours).
Complex chemical reactions occur, and certain enzymes are activated; blood becomes acidic and clots.
Cellular death (autolysis) is the final stage when all cells in the body are dead.
The time frame for autolysis depends on environmental factors, with higher temperatures accelerating cellular death.
After cellular death, the biochemical process of decomposition begins.
Decomposition continues until the body is completely skeletonized.
PROCESS OF DEATH:
Somatic Death: the cardiac activity stops, no respiration or movement
Cellular Death (Autolysis): metabolism ceases, all cells are dead
ESTIMATING THE TIME OF DEATH:
Late post mortem stages involve algor, livor, and rigor mortis.
These conditions usually begin 2-4 hours after death and continue for about 48 hours.
Algor mortis: Body's temperature drops to the ambient environment; influenced by pre-death temperature, clothing, environment, body size, and containment.
Livor mortis: Blood pools and clots where there's no pressure, causing bruise-like coloring; patterns reveal body position at death.
Livor mortis detectable 15-20 minutes after death, advances in 4-6 hours, used to estimate postmortem interval.
Rigor mortis: Stiffening of muscles due to lactic acid buildup, starts in small muscle groups, lasts 24-48 hours, influenced by factors like temperature and physical activity.
Algor, livor, and rigor mortis are independent and subject to environmental and physical factors.
Estimating time of death within 48 hours is more reliable; beyond that, accuracy decreases.
Legal time of death when pronounced by a coroner or medical examiner, may differ from physiological time of death assessed by a pathologist based on remains' condition.
Death cannot be experienced by the individual; it can only be observed in the other (Immanuel Kant,1724 - 1804)
The Decomposing Body:
Putrefaction: the process of decaying or rotting of a body or other organic matter
Purge Fluid: decomposition fluid that may exude from the oral and nasal passages as well as other body cavities
Decomposition stages help estimate the postmortem interval.
Rate of decomposition depends on factors like body size, age, environmental conditions, insect activity, climate, animal scavenging, water, and soil composition.
Decomposition can occur rapidly in hot, humid climates or persist for years in cold, dry climates.
Early stages of decomposition involve internal changes due to microorganisms in the body.
Bacteria and protozoa in the intestinal tract cause rapid swelling, bloating, and the release of gases and acids.
Bacteria hemolyze blood, creating green and red marbling around thighs, back, and shoulders.
Later stages of putrefaction involve the entire body becoming bloated, collapsing, and leaking purge fluid.
Distinct odors are produced by volatile organic compounds (VOCs) like cadaverine and putrescine.
Flesh blackens, and organs and tissues take on a creamy consistency in the stage known as black putrefaction.
The body progresses to fermentation and molding, then dry decay.
Adipocere (a waxy substance) can form on soft tissue and bone, preserving surface features of the body if left undisturbed.
STAGES AND THE STAGE OF REMAINS:
Initial decay: Microorganisms are active internally, extensive gases produced, body intact and fresh in appearance
Putrefaction: Intensified microbial activity, internal gas causes rapid bloating, purge fluid builds up and leaks, strong door of decay
Black Putrefaction: Body collapses with increased pressure, gases and purge fluid drain, very strong odor of decay, mottled and blackening of exposed flesh, internal organs and tissues break down into a creamy consistency
Butyric fermentation: biochemical fermentation of exposed flesh, issues begins to dry slowly, flesh becomes a firm, cheesy consistency
Dry Decay: Flesh dries and hardens into a papery or leathery texture
Skeletonization: Soft tissue slowly disintegrates, bone becomes more exposed, tendons, ligaments and/or cartilage break down slowly and some may be intact, environmental factors determine the level and process of decay in bone
Physical Variables Affecting the Rate of Decomposition:
Small vs Large body size: Small bodies decomposes at a faster rate than large bodies
Whole vs Wounded / dismembered: Whole bodies decompose at a slower rate than wounded or dismembered parts, there are more tissues and openings available for microbial and insect infestation in the wounded/dismembered body accelerating decay
Nude vs Clothed and/or wrapped: Nude bodies decompose at a faster rate due to exposure to elements, heavy clothing or wrapping around body slows rate of decomposition
Contained and buried vs Not contained and buried: Contained and buried bodies decompose at a slower rate
Skeletonization:
The final stage of decomposition is skeletonization.
Soft tissue is mostly gone, exposing the bone, with ligaments, tendons, and cartilage often still intact.
Environmental factors determine the fate of ligaments, tendons, and cartilage, as they may dry, crack, and disintegrate.
Bones may have a greasy texture if fatty tissue is still present.
Greasy bones with a brown to dark yellow color suggest remains are months old.
Fatty tissue dries up over time, causing bones to whiten when exposed to sunlight and extreme weather.
Bones exposed to the elements for many years may crack and chip (exfoliate).
Buried bones can absorb soil contents and become stained, especially in acidic soils, which may lead to disintegration.
The rate of skeletonization and bone decomposition varies based on factors such as burial conditions, climate, and environmental conditions, ranging from weeks to years.
Insect Activity:
Insect activity significantly influences the rate and condition of decomposition.
Decaying flesh's odor attracts carrion insects, especially in outdoor or well-ventilated indoor environments.
Insects scavenge and reproduce in soft tissues, body openings, and exposed flesh from wounds.
Insect activity can accelerate decomposition, reducing a body to bones within a week, especially in hot and humid environments.
The type and species of insects involved depend on the ecological area and the time of year.
Blow flies and flesh flies are common at death scenes, laying eggs or larvae in wounds and body openings.
These insects voraciously feed on tissue during their developmental stages and can skeletonize a body in a matter of days to weeks.
Observing the level and stages of insect activity is crucial for estimating the time of death.
Forensic entomologists collect insect samples to assess their arrival time and use the insect type and age to determine the postmortem interval.
Bodies in Water:
Determining the time of death for bodies found in water is challenging.
Water temperature, salt or freshwater, local tides, body injury, and scavenging affect decomposition rate and body condition.
Water temperature plays a crucial role; the body's core temperature matches ambient water temperature in about 5-6 hours.
Drowning victims or bodies thrown into water usually sink initially and resurface due to putrefaction gases.
Putrefaction is slower in cold and salt water; bodies may rise after 2-3 weeks.
In very cold, deep water, bodies may never resurface, while in warm, shallow water, they rise in 8-10 days.
Heavy clothing or weights may not prevent rising after bloating begins.
Underwater, there are swelling patterns during putrefaction, with hands, feet, and outer skin layers separating after 5-6 days.
Fragile body tissues in this stage often sustain damage when retrieved from the water.
Bodies typically float head down in water, affecting livor mortis presentation.
Signs of instantaneous rigor may be present in bodies found early.
Postmortem injuries in drifting bodies include cuts, abrasions, tearing, and dismemberment caused by rocks, watercraft, and sea life.
Environmental variables affecting the Decomposition Rate:
Cold Climate: Decomposition rate slowed, can be completely prevented if body is frozen, frozen bodies that are thawed decompose rapidly, in cold, dry climate decay is slower than in cold, humid climate, decay is slower in cool, shaded areas
Hot Climate: Hot, humid weather accelerates decomposition, decomposition is slow in hot and dry climate, Dry heat desiccates flesh, preserving skin and hair (mummification), In direct sunlight, dry decay is accelerated
Moist and/or acidic soil: Decomposition rapid if body buried in these types of soil
Sand, clay and gravel soils with high pH / alkaline levels: Decomposition is slower if body buried in these soil types
Presence of water: Bodies submerged in water will decompose slower than bodies on land, unless scavenged by aquatic organisms (fish, turtles, crustaceans), decomposition is delayed in bodies submerged in very cold to freezing water
Insect activity: Accelerates decomposition
Animal / bird scavenging: Promotes and accelerates decomposition