forensics study guide part 3 ( pages 9-18)

Ventricular fibrillation: Ventricular fibrillation is a life-threatening cardiac arrhythmia characterized by rapid and chaotic electrical activity in the ventricles (lower chambers) of the heart. Instead of coordinated contractions, the ventricles quiver and are unable to effectively pump blood to the body. Ventricular fibrillation can lead to cardiac arrest and sudden cardiac death if not promptly treated with defibrillation (electric shock) to restore a normal heart rhythm.

Respiratory depression and paralysis: Respiratory depression refers to a decrease in the rate and depth of breathing, resulting in inadequate oxygen intake and carbon dioxide elimination. It can be caused by various factors, including drug overdose (such as opioids or sedatives) or severe medical conditions affecting the respiratory system. Respiratory paralysis, on the other hand, refers to a complete loss of muscle control involved in breathing, leading to the inability to breathe spontaneously. Both respiratory depression and paralysis can have serious consequences, including hypoxia (oxygen deprivation), respiratory failure, and potentially death if not promptly treated.

Cardiac tamponade: Cardiac tamponade is a medical emergency that occurs when fluid (such as blood) accumulates in the pericardial sac surrounding the heart, exerting pressure on the heart and compromising its ability to pump effectively. It can result from various causes, including trauma, infections, or certain medical procedures. The pressure on the heart restricts its filling and compromises blood flow, leading to decreased cardiac output and potential shock. Symptoms of cardiac tamponade may include shortness of breath, chest pain, low blood pressure, and weak pulse.

• Hypoxia/Asphyxia:

  • Mechanism: Oxygen deprivation leading to inadequate supply to tissues and organs.

  • Causes: Suffocation, strangulation, drowning, inhalation of toxic gases, smothering.

• Hemorrhage/Exsanguination:

  • Mechanism: Excessive bleeding resulting in severe loss of blood volume.

  • Causes: Trauma, arterial or venous injury, ruptured blood vessels, gunshot wounds.

• Cardiac Arrest:

  • Mechanism: Sudden cessation of heart function leading to the stoppage of blood circulation.

  • Causes: Heart attack (myocardial infarction), arrhythmias, drug overdose, electrical shock.

• Neurological Injury/Brain Damage:

  • Mechanism: Severe injury or damage to the brain affecting vital functions and leading to death.

  • Causes: Traumatic brain injury, stroke, cerebral hemorrhage, brain tumors.

• Toxicological:

  • Mechanism: Poisoning or overdose of a toxic substance resulting in organ dysfunction.

  • Causes: Ingestion, inhalation, or injection of poisonous substances such as drugs, alcohol, chemicals, or heavy metals.

• Infection/Septicemia:Mechanism: Systemic infection causing a severe inflammatory response and organ failure.

• Causes: Bacterial, viral, or fungal infections that spread throughout the body.

• Shock:

  • Mechanism: Inadequate perfusion of organs and tissues due to low blood pressure or decreased blood volume.

  • Causes: Hypovolemic shock (blood loss), cardiogenic shock (heart failure), septic shock (infection), anaphylactic shock (allergic reaction).

• Organ Failure/Multiple Organ Dysfunction Syndrome (MODS):

  • Mechanism: Failure of multiple organs leading to a cascading decline in physiological function.

  • Causes: Sepsis, severe trauma, massive burns, drug overdose.

• Metabolic Disturbances:

  • Mechanism: Severe disruptions in metabolic processes affecting vital functions.

  • Causes: Diabetic ketoacidosis, electrolyte imbalances, severe liver or kidney failure.

• Electrocution:

  • Mechanism: Death caused by exposure to an electric current.

  • Causes: Electrical accidents, lightning strikes.

• Heat Stroke/Hypothermia:

  • Mechanism: Extreme temperatures causing the body to overheat or cool down significantly, leading to organ failure.

  • Causes: Prolonged exposure to high heat (heat stroke) or extreme cold (hypothermia).

1. What are rigor, livor, and algor mortis?

Rigor mortis is the stiffening of muscles that occurs following death (disappears after 36-48 hrs postmortem) 

• Starts within two hours after death gid state 

• Starts in the head and gradually works its way to the legs 

• After 12 hrs, the body is at its most rigidgor.

• It’s probably been dead less than 2 hrs or more than 48hrs if the body shows if body shows no sign of visible rigor

  • Factors that affect E.g. ambient temp., person’s weight, type of clothing, illness, level of physical activity shortly before death, sun exposure

  • Muscles that gain its rigor first, would also lose its first

    Livor mortis (lividity) is discoloration of the body that occurs from the settling of red blood cells after the blood stops circulating. (last 12-36 hrs postmortem)

    • Onset: Livor mortis begins to develop within 2 to 4 hours after death, although it may become visible sooner in some cases. The process continues to progress and generally reach its peak at around 6-12 hours. 

    
    

    • Appearance: Lividity presents as a purplish-red or bluish discoloration of the skin. The color is a result of deoxygenated blood pooling in the blood vessels. The discoloration is more prominent in areas of the body that are in contact with a surface or facing downward due to gravity.

    
    

    • Settling: The blood settles in the dependent areas of the body due to gravity. If the body is lying on the back, lividity will be most noticeable on the back, buttocks, and back of the thighs. If the body is lying on the front, lividity will be visible on the front of the body, face, and extremities.

    
    

    • Fixation: Lividity becomes fixed or permanent after approximately 6 to 12 hours. This means that if the body is moved or repositioned after this time, the lividity pattern will not change.

    
    

    • Ending: Lividity does not “end” in the literal sense but rather fades away during the time from 12-36 hours postmortem when the body begins to decompose. 

    
    

    • Pressure Pale: If pressure is applied to an area of lividity, such as by pressing a finger into the skin, the blood will temporarily drain from that area, and the skin will appear pale. Once the pressure is released, lividity will reappear.

    
    
    Livor mortis can be influenced by factors such as body position, temperature, and blood viscosity.

    
    

    Algor mortis is the cooling of the body that occurs after death. The general rule of thumb for a nearly nude body exposed to 18° to 20°C will 1.5°C of temperature drop per hour for the first 8 - 12 hours.

    
    

    Yet, this is very ambiguous as external factors such as humidity, clothes, temperature, and humidity can influence algor mortis. 

    
    
    

    1. What are the 4 types of traumatic deaths?

    Mechanical: Mechanical trauma refers to injuries caused by physical force or mechanical means. This can include blunt force trauma, sharp force trauma, or injuries caused by crushing, shearing, or tearing.

    Thermal: Thermal trauma refers to injuries caused by extreme temperatures or thermal energy. Examples of thermal trauma include burns (hypertherma) and frostbites (hypotherma)

    Chemical: Chemical trauma refers to injuries caused by exposure to hazardous or toxic substances. Examples of chemical trauma include inhalation, interaction, and injection of toxins.

    Electrical: Electrical trauma refers to injuries caused by exposure to electric current. Examples of electrical trauma include: Electrocution from high-voltage electrical shocks, results in cardiac arrest such as Ventricular fibrillation (a life-threatening cardiac arrhythmia characterized by chaotic and irregular electrical activity in the ventricles, the lower chambers of the heart) or severe internal injuries, electric burns (often have distinct entry and exit), and neurological effects like seizures and loss of conscious. 

    2. What are the 2 types of mechanical trauma?

    Mechanical trauma is divided into two categories which are sharp and blunt force. 

    Sharp Force: rarer but almost always homicide; knives, etc.

    Blunt force: non-penetrating; walls, cars, etc. that kill by impact or lead to brain injury or organ failure

    3. What is the difference between blunt force trauma and sharp force trauma? 

    Blunt force is caused by dull or non-sharpened objects, often a result of direct contact with walls, cars, etc. that kills one by impact or leads to brain injury or organ failure. For sharp force trauma refers to injuries caused by sharp implements that penetrates the body, potentially from knives, etc.

    
    
    

    4. What’s the difference between a penetrating gunshot wound and a perforating gunshot wound?A penetrating gunshot wound occurs when the object enters the body and remains inside.( entrance by no exit) However, for perforating wounds, the object passes right through the body ( entrance and exit)

       1. Gunshot wounds are a special form of blunt force trauma.

       2. What are the types of wounds?

       Incision: An incision is a clean, straight cut made by a sharp-edged object, such as a knife or a scalpel. The wound edges are typically smooth and well-defined.

       Laceration: A laceration is a jagged or irregularly-shaped wound caused by tearing or stretching of the skin and underlying tissues. It often occurs due to blunt force trauma or sharp objects with uneven edges. Bigger in scale compared to incisions. 

       Amputation: Amputation refers to the complete removal or separation of a body part or limb from the rest of the body. It can occur due to trauma, surgical intervention, or other circumstances.

       Abrasion: An abrasion is a superficial wound caused by the rubbing or scraping of the skin against a rough surface. It typically involves the removal of the top layer of skin, resulting in a "scraped" appearance.

       Puncture: A puncture is a wound caused by a sharp, pointed object penetrating the skin and underlying tissues. It creates a small, deep hole in the skin, and the underlying tissues may be affected depending on the depth and force of the puncture.

       Avulsion: An avulsion is a type of wound where a portion of the skin or tissue is forcibly torn away or separated from the body. It often occurs in accidents involving shearing forces or high-velocity trauma.

       Contusion: A contusion, commonly known as a bruise, is a result of blunt force trauma that causes blood vessels beneath the skin to rupture. It leads to bleeding and discoloration of the skin, but the surface of the skin is not broken. Hematoma is also a contusion but can be at a larger scale when larger blood vessels and organs are damaged which leads to mass collection of blood underneath the skin. 

       3. How can you tell if trauma is antemortem or postmortem?

       • Mortem= death 

       Antemortem injuries (Injuries sustained before death) show inflammation while postmortem injuries (Injuries after death) don’t. Antemortem injuries show signs of bleeding while often, postmortem do not(except in cases of drowning, scalp wound, etc.) After death, blood pools to the bottom of the body (gravity), causing hemorrhaging that can be confused with antemortem bruising (bruised appearance in the lower limbs, arms, hands, and feet known as lividity)

       Antemortem- While the person is still alive, the blood is circulating and any injuries such as cuts or stabs will bleed

       Postmortem- After death, the body usually does not bleed. 

       • However, there are exceptions. For instance, when a person drowns, their body usually floats face down and this results in the head becoming congested with blood. 

       • If the cadaver receives a head injury by being buffeted around in the water and colliding with boats or propellers, then there could be some evidence of bleeding. 

       • Scalp wounds sustained after death may also leak some blood.

       
       
       

       Forensic Anthropology: Chapter 6 

       1. What are the 3 tasks of forensic anthropology?

       Identifying and providing a biological profile for the victim, a taphonomic assessment, and providing data and evidence of trauma at the perimortem period.

       2. What is included in a biological profile?

       Sex, age, stature, ancestry/race, healed bone fracture, dental configuration, etc.. 

       • Some more specific information like name of the victim may or may not be included if the info is not available 

       
       

       3. What’s the difference between deciduous and permanent dentition?

       Deciduous dentition is the 20 baby teeth that will be replaced by adult teeth. 8 incisors, 4 canines, 8 molars.

       
       

       Permanent dentition is the 28 or 32 (when there’s two pairs of wisdom teeths) adult teeth. 8 incisors, 4 canines, 4 premolars, 8/12 molars.

       
       

       4. How do you determine the sex and age of the victim?

       Age: The area where the left and right pelvises meet become more flattened and rimmed with age. Dentition, bone density, epiphyseal fusion, and suture fusion can indicate age. 

       Sex: The female pelvis is wider than the male pelvis. Males have larger, more pronounced jaw bones (more right angled of the bottom jaw) as well as more prominent eyebrow ridges. Males typically have thicker bones and longer femurs.

       5. What are the 3 levels of certainty when identifying a victim?

       Lowest-probable → medium-probable → highest-probable beyond a reasonable doubt (includes DNA identification, dental match, etc.)

       6. In cases of suspicious death, most medical examiners and coroners require positive identification— that is, identification beyond a reasonable doubt. 

       7. What must the basic anthropological record include? 

       • chain of custody

       • taphonomic assessment

• biological profile (age, sex, ancestry, stature, anomalies, pathology)

• identification characteristics and interpretation

• description of trauma

1. Dental development is more precise when guessing the age of who? 

1. Children

2. Boomers 

3. Females 

4. Male

      9. When does the skeletal morphology increase? 

1. Fetal stage 

2. Puberty

3. Post-puberty

4. Mid-life crisis 

     10. When determining forensics ancestry, what bone is most often used?

1. Pelvis 

2. Skull

3. Funnybone

4. Spine 

     11.. What are the three races anthropologists use to identify the individual?

1. Western European 

2. Asian/Native American 

3. African

4. All of the above

     12. What bones can be used to determine the biological sex of the individual?

1. Pelvis 

2. Skull

3. Humerus 

4. a and b

5. b and c 

Forensic Entomology: Chapter 7

1. What are two ways of estimating time of death using entomology?

1) Development of blow flies (or any carrion insects) over time (few hours to several weeks) 

1. If a corpse contains blowfly eggs, then the approximate time of death would be 24 hours or less.

2. If a corpse contains third-stage larvae, then the time of death is approximately four to five days.

3. If a corpse contains pupae, then the time of death would be approximately 18 to 24 days.

2) Successional colonization of the body by a sequence of carrion insects (any time after death). By examining the types and stages of insects present on the body,

entomologists can estimate the postmortem interval (PMI), which is the time elapsed since death. 

5 stages of decomposition: 

• Fresh Stage (Fresh/Early Decomposition): This stage begins immediately after death and lasts for a few days. The body appears fresh and shows few signs of decomposition. The presence of flies and other insects attracted to the body may also be observed.

• Bloat Stage (Putrefaction): In this stage, which typically occurs within 2-3 days after death, the body begins to bloat due to the increased production of gases by bacteria. Maggots and other fly larvae are commonly found feeding on the decomposing remains.

• Active Decay Stage (Black Putrefaction): This stage occurs around 1-2 weeks after death. The body experiences extensive tissue breakdown, resulting in discoloration, liquefaction, and strong odors.Insects, such as beetles and additional fly species, continue to feed on the decaying tissue.

• Advanced Decay Stage (Butyric Fermentation): This stage occurs several weeks after death. The decomposition fluids seep into the soil, leaving behind a dark-colored stain called a cadaver decomposition island. Insects and other scavengers, including carrion-feeding beetles and mites, are actively present.

• Dry Remains Stage (Dry Decay/Skeletonization): In this final stage, which can occur several months to years after death, the majority of soft tissues have been consumed or decayed, leaving behind dried, skeletal remains. Scavenging insects and other organisms may continue to feed on remaining tissues. 

1. What are the 4 things an entomologist must know when using blow flies to determine time of death?

1) the oldest stage of blow fly associated with the body 

2) the species of insects 

3) temperature data-rate of development is highly dependent on weather 

4) developmental data

2. How can entomologists determine if a body was moved?

If some insects found on the body are inconsistent with the habitat around the body, it indicates that the body has been moved.

3. How is entomology used? 

1. Estimate time of death

2. Find disturbances done to the body

3. Determine presence/position of wound sites

4. All of the above

5. What insect’s development is observed?

1. Butterfly

2. Mosquitos

3. Blowfly

4. Fly high

      6. At what stage are the maggots feeding on liquid protein? 

   1. First instar

   2. Second instar

   3. Third instar

   4. Fourth instar 

         7. What insects can be used to obtain DNA?

   1. blowfly/maggots

   2. Fleas

   3. Bed bugs

   4. All of the above

         8. What are some methods in cases of homicide that can prevent insects from colonizing the    body? - Burning, burying, thoroughly cleaning the scene, wrapping the body, using chemicals, etc..

   
   
   
   

   Maggot debridement therapy (MDT) is a medical method that utilizes sterile maggots (larvae) of certain fly species, typically Lucilia sericata or Phaenicia sericata, to remove necrotic (dead) tissues from wounds and promote the healing process