Meaning, Manner, Mechanism, Cause, and Time Death Meaning, Manner, Mechanism, Cause, and Time

Forensic Entomology Flies arrive within 10 minutes of death Fly predators such as wasps arrive within 3-7 days Ants, cockroaches, and beetles arrive within 8-18 days

Insects are ectothermic-body needs to be warmed by outside to be able to grow Will speed up process in hot climates/slow in cold regions Drugs – cocaine will speed up life cycle Drugs – poisons (arsenic) will slow down

Back in the day… 17th century: anyone in a coma or with a weak heartbeat was presumed dead & buried People had a fear of being buried alive. There were “waiting mortuaries”

Meaning of Death End of life “Irreversible cessation of circulation of blood” Brain activity stopped Cells begin to die, known as cell autolysis

Medical Examiner vs Coroner Medical examiner (M.E.) Medical doctor who conducts examination on deceased Conducts autopsy (post-mortem) Coroner An elected position. Can not perform an autopsy

the cause, the mechanism, and the manner of death. When a death occurs, the medical examiner must fill out a death certificate. In order to properly complete this document, they must determine three things: the cause, the mechanism, and the manner of death.

There is often confusion about which is which. The cause of death is the disease or injury that produces the physiological disruption inside the body resulting in death For example, a gunshot wound to the chest. The mechanism of death is the physiological derangement that results in the death. An example of a mechanism of death due to the gunshot wound described above is exsanguination (extreme blood loss).

Manner of death Cause of death Mechanism of death Time of death Category Event leading to death Specific body failure When they died Manner of death Cause of death Mechanism of death Time of death

Manner of Death Natural Accidental Suicidal Homicidal Undetermined Interruption and failure of body functions resulting from age or disease Caused by unplanned events Purposefully killing oneself Caused by another person; murder

Quick Check!!!! A man with a heart condition is attacked and dies from a heart attack during the assault. Is the MOD accidental or homicide? An elderly woman dies after being kept from receiving proper health care by her son. Is the manner of death natural or homicide?

Cause of Death (COD) Natural causes Heart disease Cancer Stroke Respiratory Disease Accidents

Cause of Death (COD) Homicide/Suicide Poisoning Hanging Drowning Shooting

Mechanism of Death (specific body failure) Cause: Shooting Strangulation Drug Overdose Mechanism: Exsanguination (bleed to death) Asphyxiation (lack of oxygen) Hypoxia (lung failure)

Factors to Determine Time of Death (TOD) Changes of the eye Stages of decomposition Insects (forensic entomology) Livor Mortis Rigor Mortis Algor Mortis Stomach and intestinal contents

Time of Death (TOD) Livor mortis Rigor mortis Algor mortis Death color – pooling of blood in tissues after death (lividity) Death stiffness – stiffening of skeletal muscles after death Death heat – cooling of body after death

Livor Mortis Lividity: pooling of blood in body Begins 2 hrs. after death Caused by the break down of red blood cells 2-8 hrs.: color disappears when skin is pressed >8 hrs.: permanent discoloration

Livor Mortis The ambient temp affects time for lividity to set in Hot, summer day – blood pools faster Cool room: slower process Can determine if body was moved Dual Lividity

Rigor Mortis Cause: no oxygen to cells  calcium buildup  muscle fibers remain contracted Starts 2 hrs. after death Starts and stops from head  legs 12 hrs: most rigid Stiffness disappears completely after 36 hrs.

Factors affecting rigor mortis: Ambient temperature Person’s weight Type of clothing Illness Level of physical activity shortly before death Sun exposure

Algor Mortis Literally means DEATH HEAT Temperature loss in a corpse Thermometer inserted in liver 1 hr. after death: cools 1.4°F per hour 1-12 hrs: cools 0.7°F per hour until it reaches surrounding temperature

Factors affecting algor mortis: Environment – lose heat faster (cold), lose heat slower (hot) Wind – more wind  fast heat loss Excess body fat – slows heat loss Clothing – slows heat loss Rule of thumb: 1°F per hour

Stomach and Intestinal Contents TOD 0-2 hours after last meal: undigested stomach contents present TOD 4-6 hours after meal: stomach empty, food in small intestine TOD 12+ hours after meal: waste in large intestine

The eye after death A thin film starts to develop minutes after death on the surface of the eye Called a corneal film

Stages of Decomposition 0-2 Days: Cell autolysis Flies lay eggs on corpse Green, purplish staining Skin: marbled appearance Face discolored

Stages of Decomposition 4 Days: Skin blisters Abdomen swells (CO2 gas released by bacteria in intestines) Maggots on corpse

Stages of Decomposition 6-10 Days: Corpse bloats with CO2, chest and abdomen burst and collapse Fluids leaks from body openings Eyeballs and other tissues liquefy Skin sloughs off More eggs, maggots, flies, and beetles

Stages of Decomposition 10-20 Days: Bloated body collapses Flattened body, creamy flesh Strong smell of decay Fluids drain and seep 50-365 Days: Body dry; decays slowly Hair disappears, leaving bones