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CAUSE OF DEATH, MANNER, MECHANISM Forensic Pathology.

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Presentation on theme: "CAUSE OF DEATH, MANNER, MECHANISM Forensic Pathology."— Presentation transcript:

1 CAUSE OF DEATH, MANNER, MECHANISM Forensic Pathology

2 Role of the Medical Examiner How is a coroner different from an ME? Coroners are elected officials. They require no formal training. The coroners are actually part of the judicial body, a tradition that comes from England. Around the early 1900s, local scandals were becoming more widespread by coroners that had no training. Medical examiners began replacing coroners in large cities. They required formal training and had to pass a test to be licensed.

3 Pathologists Pathologists began appearing in hospitals as microscopes became more advanced, in the mid 1850s. Pathologists studied diseases, causes and diagnosis. Many pathologists study tissues and biological fluids. By the end of WWII, forensic pathology was a recognized specialty and now, medical examiners in large cities are usually required to be forensic pathologists as well.

4 Training Required Medical School- 4 years Post-medical school training, usually in a hospital pays about $20,000 per year One more year of post graduate training is required and usually pays around $50,000 per year. A 2-3 day examination must be passed at this time to become board certified. Several also go to law school to obtain a J.D. (juris doctor) degree since there is so much intersection with the law.

5 Duties of a Forensic Pathologist Reviewing Medical history of victim Reviewing witness statements Scene examination (especially when death is complicated) Autopsy examination- better term is necropsy Obtaining appropriate samples for toxicology, microscopic examination and DNA Photography Report preparation Testimony in court

6 Cause of Death The disease or injury that led to death The cause is the underlying cause, even if other complications or contributing factors were involved. Mechanism of Death- the biological or physiological abnormality produced by the cause of death that is incompatible with life

7 Manner of Death There are only 4: 1) Homicide- acts from which a reasonable person would have expected bodily harm or death conducted by another party 2) Suicide- acts from which a reasonable person would have expected bodily harm or death conducted by ones self 3) Accidental- trauma occurring from acts no reasonable person would have anticipated producing bodily harm or death 4) Natural- solely caused by disease

8 Time of Death Rigor mortis- stiffening of muscles that occurs when glycogen (which causes contraction of muscles) is used up but not reformed Usually begins around 4 hours after death and subsides between 24 and 36 hours Exercise before death and electric shock can quicken the presence of rigor mortis

9 Time of Death Livor mortis or lividity- discoloration of the body where red blood cells settle after blood stops circulating  Can be seen within an hour of death in light skinned individuals  May not be seen in dark skinned individuals, or those who lost a lot of blood volume  Slowly disappears with decomposition after 36 hours Algor mortis- cooling of the body that occurs after death (assuming ambient temperature is lower than body temp.) Assumed that a nearly nude body exposed to ° C temp will decrease 1.5° C per hour for 8 hours after death. Many extenuating circumstances can affect body temp!

10 Classification of Traumatic Deaths 1) Mechanical- sharp and blunt force trauma 2) Thermal- hypo or hyperthermia, exposure to excessive cold or hot temps. 3) Chemical- death by use of drugs or poison, ethanol involved deaths account for more than 50% of traumatic deaths 4) Electrical- passage of electrical current through the body to produce ventricular fibrillation causing death Note: Asphyxial death, death that occurs as a result of lack of oxygen to brain, overlaps other causes: may be due to strangulation (mechanical), poisoning (chemical) or low voltage electrocution (electrical).

11 Mechanical Trauma 1) Sharp force trauma-  injuries received from sharp implements, like knives, swords, axes  Amount of fore required to exceed tensile strength of tissue is much less than blunt objects require  Produce incised wounds, which have sharp edges that distinguish sharp force from blunt force injuries  Death most commonly arises from exsanguination, when a major artery or the heart is damaged

12 Mechanical Trauma 2) Blunt force trauma- - most commonly causes death when the brain has been significantly damaged - however, lacerations, cuts from blunt force trauma, can cause exsanguination also - firearms cause a special kind of blunt force trauma, several distinctions can be made including type of weapon, velocity of projectile - High velocity projectiles (greater than 300 m/s) are usually only seen by high powered rifles (hunting and military)

13 Mechanical Death Blunt force trauma continued-  - Often times contusions are present, accumulation of blood in tissues outside of the blood vessels. The pattern in the contusion may be transferred from the striking object.  - Hematomas are “blood tumors” which are contusions with more blood present.  Gunshot exit wounds are typically lacerated, and most are larger than entrance wounds.

14 Chemical Trauma Ethanol is the drug that is complicit in 50% of all traumatic deaths. It can also kill directly through alcohol poisoning. People generally go into a coma and then die due to lack of oxygen. Carbon monoxide and cyanide are also poisons that are used to induce death. In California, the authorities used potassium cyanide tablets that were dropped in hydrochloric acid to produce hydrogen cyanide gas in gas chambers.

15 Electrical Trauma Low voltage electrocution causes ventricular fibrillation, this is defined as a non-propulsive quivering that leads to nonresucitability within minutes. High-voltage direct current (DC) tends to cause a single muscle spasm, often throwing the victim from the source, resulting in a shorter duration of exposure but increasing the likelihood of traumatic blunt injury. Alternating current (AC) is said to be about three times more dangerous than direct current of the same voltage, because continuous muscle contraction, or tetany, occurs when the muscle fibers are stimulated at between 40 and 110 times per second. The frequency of electrical transmission used in the United States is 60 Hz. Tetany occurs even at very low amperages. It has been customary to use the terms "entry' and "exit" to describe electrical injuries. Particularly with AC, this is clearly a misnomer and the terms should correctly he "source" and "ground." The hand is the most common site of contact as it grasps a tool coming into contact with an electric source. Although all the muscles of the arm may be tetanically innervated by a shock, the flexors of the hand and forearm are much stronger than the extensors so that the hand grips the source of the current. At currents above the let-go threshold (6 to 9 mA), this can result in the person's being unable to release the current source voluntarily, prolonging the duration of exposure.

16 Legal Definitions of Homicide “Homicide is a legal term for any killing of a human being by another human being. Homicide itself is not necessarily a crime --some homicides are legal, such as a justifiable killing of a suspect by the police or a killing done in self-defense -- but unlawful homicides are classified as crimes like murder and manslaughter.”~ manslaughter html

17 First Degree Murder The rules vary somewhat from state to state as to what circumstances make an intentional killing first degree murder. The following circumstances commonly make an intentional killing first degree murder: The killing is deliberate and premeditated. The killing occurs during the course of a dangerous felony. The killer uses an explosive device such as a bomb. In terms of punishment, many states have mandatory minimum sentences for murder. The mandatory minimum for first degree murder is almost always higher than for second degree. Defendants convicted of first degree murder can also be eligible for a state's ultimate penalty. Currently, in 36 states and under some federal laws, the ultimate penalty is death. In others, the ultimate penalty is life in prison without the possibility of parole (LWOP).

18 Second Degree Murder Defendants convicted of second degree murder are often sentenced to a term of years rather than to life in prison and are almost always eligible for parole. Second-degree murder is ordinarily defined as: 1) an intentional killing that is not premeditated or planned, nor committed in a reasonable "heat of passion"; or 2) a killing caused by dangerous conduct and the offender's obvious lack of concern for human life. Second-degree murder may best be viewed as the middle ground between first-degree murder and voluntary manslaughter.

19 Manslaughter Manslaughter (in some states called third degree murder) is an unlawful killing that does not involve malice aforethought. The absence of malice aforethought means that manslaughter involves less moral blame than either first or second degree murder. Thus, while manslaughter is a serious crime, the punishment for manslaughter is generally less than it would be for murder. Voluntary manslaughter. This is often called a "heat of passion" crime.

20 Manslaughter Involuntary manslaughter. A killing can be involuntary manslaughter when a person's reckless disregard of a substantial risk results in another's death. Because involuntary manslaughter involves carelessness and not purposeful killing, it is a less serious crime than murder or voluntary manslaughter.

21 Murder and Manslaughter: Case Example 1 Facts: Fast Boyle is walking along a busy street. Clay bumps into Boyle and continues walking without saying "Sorry." Angered by Clay's rudeness, Boyle immediately pulls out a gun and kills Clay. Verdict: Boyle could probably be convicted of second degree murder, because Boyle killed Clay intentionally. A judge or jury is unlikely to conclude that the killing was premeditated, which would elevate the shooting to first degree murder. On the other hand, this was not a heat of passion killing that might reduce the conviction to voluntary manslaughter. While Boyle might personally have been provoked into killing Clay, the circumstances were not so extreme that many ordinary and reasonable people would have been provoked to kill.

22 Murder and Manslaughter: Case Example 2 Facts: Standing next to each other in a bookstore a few feet away from the top of a flight of stairs, Marks and Spencer argue over the proper interpretation of free will in Hobbes's philosophy. The argument becomes increasingly animated and culminates when Spencer points a finger at Marks and Marks pushes Spencer backwards. The push is hard enough to cause Spencer to fall backwards and down the stairs. Spencer dies from the resulting injuries. Verdict: Marks would probably be guilty of involuntary manslaughter. It was criminally negligent of Marks to shove a person standing near the top of a stairway. But circumstances don't suggest that Marks's behavior was so reckless as to demonstrate extreme indifference to human life, which would have elevated the crime to second degree murder.

23 Murder and Manslaughter: Case Example 3 Facts: Lew Manion comes home to find that his wife Lee has been badly beaten and sexually abused. Manion takes Lee to the hospital. On the way, Lee tells Manion that her attacker was Barnett, the owner of a tavern that she and Manion occasionally visit. After driving Lee home from the hospital about four hours later, Manion goes to a gun shop and buys a gun. Manion then goes to the tavern and shoots and kills Barnett. Verdict: Manion could be convicted of first degree murder, because his purchase of the gun suggests that the shooting was intentional and premeditated. Voluntary manslaughter is a somewhat less likely alternative. Most judges and jurors are likely to think that enough time elapsed between the time Manion found out about Lee's injuries and the time he shot Barnett for any heat of passion to have cooled. Manion should have left his gun at home and reported the crime to the police.


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