Exam 2
Wadding
- A disc composed of cork or cardboard used to separate the shot from the gunpowder and creates a more efficient explosion by containing the gas in the gunpowder area of the shot shell
Projectile
- A generic term used to describe anything exiting a weapon, In wounds created by guns it is typically the lead bullet, but in some weapons, such as a dart gun or handmade ammunition, it made be atypical
Handgun
- A handheld weapon that varies from low to high velocity depending on the capability of that gun's barrel diameter corresponding to caliber, barrel length, and type of ammunition used -revolver -semi-automatic
Shotgun
- A high-velocity weapon that utilizes shot shells rather than bullets as projectiles and is usually described by gauge rather than caliber - Single or double barrel, stock, magazine, trigger, pump-action mechanism - Reload by racking back pump mechanism on the barrel - The smaller the gauge number = the larger the shotgun bore
Rifle
- A high-velocity weapon utilizing larger amounts of gunpowder and a longer barrel to achieve greater accuracy, as well as more complete burning of the powder and of which the barrel diameter is described by caliber. -Barrel, trigger, stock, firing chamber, bolt or lever action, magazine -There are semi-automatic rifles -Magazines vary in size and can hold more bullets than semi-automatic rifles -Magazines vary in size can hold more bullets than semi-automatic handguns
Semi-Automatic Handgun
- Bullet reloading mechanism - Hammer, trigger, magazine, slide, grip, barrel - Magazines vary in numbers of bullets they can hold - Rack a bullet by pulling slide mechanism to be pulled toward handgrip - Slide moves automatically after each trigger pull until magazine is empty
Lacerations
- actual tear of the skin that results when the force being applied exceeds its elastic ability to stretch, causing it to tear •Irregular margins •Avulsion - subtype of laceration - tear created a flap of skin •Tears of skin resulting when the force being applied exceeds its elastic ability to stretch •Described in length, width, depth •Laceration wound = object is blunt instrument •Incision wound = sharp edged object •Determine laceration or incision wound by examining margins and tissue between edges of wound •Laceration will have abraded margins, Incision will have smooth margins
Ricasso of knife
- at the handle portion of the blade, thicker portion called the ricasso that gives the blade strength at the junction - if the blade enters to this level it will give the wound a squared-off margin
Contusions
- commonly known as a bruise - created by force being applied to the skin causing the rupture of the small blood vessels and bleeding into the tissue under the skin surface •Created by force being applied to skin causing rupture of small blood vessels and bleeding into tissue under skin surface •Bruise •Can vary with thickness, location, how long it is present •In decedents, biopsies of bruises can be performed and dated to a range of days •Described in length and width •Can be patterned •Imprints from seatbelts or steering wheels, bats, batons, pipes -usually starts as red-purple, transitions into green-yellow, then yellow-brown -described in length and width
Handle of knife
- forms the grip area - it can be either smooth or rough in texture and contain a handhold grip or not - it may contain finger-prints if the surface has not been smeared or if the surface is not rough
Butt of knife
- refers to the base of the handle opposite of the tip - it may not leave sharp-force injuries but can be used as a blunt weapon leaving blunt-force injuries
Abrasions
- scrape on the skin causing a loss of the superficial layers of the skin -created by a force sliding across the skin or the skin sliding across a surface. -Ex) tree branch creating a scratch on someone's arm while they are trimming a tree. -Superficial injury -Described by length and width also by color (usually yellow-tan, red-brown, yellow-brown) -May occur post-mortem due to loss of the superficial layer of skin but will appear waxy yellow
Blade of knife
- the cutting portion of a knife and is tapered to a point, through a belly(mid) region before connecting to the handle. - the length of a knife is measured from the tip to the beginning of the handle
Spine of knife
- the dull edge of the blade of a knife - this edge is the portion that gives the knife thickness as compared to the tapered cutting edge
Blunt-Force injuries (Chapter 7)
- those where a force is applied to the surface of the body or where the body comes into contact with a surface causing an injury
Hangings
-A combining of a ligature around the neck and the body in a position of either partial or full suspension. -Fractures in the neck for suicide are rarely seen in hangings -The mechanism of death is usually compression of the blood flow to or from the head, rather than obstruction of the airway or fracture of the spinal column.
Primer
-A volatile explosive material that comes in contact with the firing pin and precipitates the ignition of the gunpowder explosion.
Entrance v Exit wounds
-All entrance wounds have marginal abrasions -In graze wounds, margins will be lacerated with small pointed margins pointing in direction from which bullet came from -Exit wounds are typically larger than entrance wound -Exit wound can appear round, or as a small or large laceration, or as a small slit in the skin -Exit wounds characterized by absence of marginal abrasion rather than size o No soot
Shotgun Wounds
-Appearance will differ based on distance muzzle is from skin -As muzzle increases in distance, the wound will enlarge reaching up to 1-1 1/4in in diameter -As muzzle gets further away, shot pellets disperse more widely and begin to form satellite entrance wounds around main entrance wound
Respiratory (SIDS)
-Asthma --Air can be sucked into the lungs but unable to get out -Pneumonia common cause of death in children especially if they have an underlying disease -Cystic Fibrosis --Inherited --Child lacks enzyme product that results in abnormally thick mucus and pancreatic secretions --Frequent lung infections, poor digestive functions
Anatomy of a Knife
-Blade -Spine -Ricasso -Guard or "Hilt" -Handle -Butt
Natural Disease More (SIDS)
-Cardiac --Congenital heart disease, viral myocarditis, rheumatic heart disease -Abnormalities occur at approx. 8-12 weeks -Diagnoses are occasionally missed before discharge from hospital -Clues include poor feeding, decreased growth and development, respiratory difficulties
Perforation
-Describes a wound that enters an organ and passes through it
Penetration
-Describes an entrance of a wound into an organ or body cavity and usually no exit.
Neuromuscular Disorders
-Down syndrome --Additional X chromosome- AKA Trisomy 21 --Varying degrees of mental retardation, underlying cardiac disease, early onset dementia -Hydrocephalus --Swelling of brains ventricular spinal fluid compartment --Irreversible brain damage -Cerebral Palsy --Cognitive, behavioral, and neuromuscular disorder --Degree of brain damages varies
Natural Disease (SIDS)
-Infections and sepsis --Some infants slow to mount a brisk inflammatory response --If treated with antibiotics, postmortem cultures will likely be negative due to antibiotics.
Medical History (SIDS)
-Infectious diseases more common in children who haven't been immunized -Risk from not being immunized much higher than not being immunized -Drug or alcohol use while pregnant will impact fetus -Meconium begins forming 12-15 weeks into pregnancy --Drug use during pregnancy (last 4-5 months) --Head hair samples --Some state require testing meconium on all infants -Newborns can suffer disabilities if mother uses while pregnant -Breast feeding will transfer drugs to infant
Acquired Diseases
-Ingestion of poisons or medications -Part of a scene assessment is locating parents medication and noting any cabinet locks -Confiscate bottle and fingerprint bottle -Anaphylaxis: Severe allergic response to ingested food, bee stings, skin surface application of an irritant
Extent And Duration Of Injuries
-Injuries can be narrowed down to within a range of days --Not hours or a specific time unless it was a witnessed event -Estimates made via skin biopsies, biopsies of injury sites, sampling of fractures -Gross appearance of bruises not a good indicator of age of injuries
Drowning
A body is found in water but has no diagnostic findings at autopsy -can see lungs trying to prevent water from entering them -Submerging in ice water can preserve body
Carbon monoxide
A colorless, odorless, and poisonous gas -Can be exposed and unaware
Hypoxia
A decreased level of oxygen to the brain and vital organs
Choke
A mechanism on a shotgun that is used to prevent scatter of the pellets. They come in different degrees from modified cylinder to variants of modified to full choke. -They do not affect the pattern distribution of shotgun pellets seen in ranges of fire less than 10ft.
Power piston
A plastic form of wadding that lines the inside of the shotgun shell and serves the same purpose as the cardboard disc. -It is designed to keep the shot together, creating more accuracy at the target and less fouling of the barrel by less contact with the lead.
Shotgun shell
A term used to describe the equivalent of a cartridge but used only in a shotgun. Contains the lead shot as well as the gunpowder, wadding, and primer. When all the contents are expended it is called a shot case.
Foreign Objects (SIDS)
Airway obstructions -Coins, pieces of toys, candy, paper, etc. -Finger sweep of the mouth -Heimlich (now conscious or unconscious chocking patient) -Symptoms include inability to talk or cry with raspy breathing and panicked expression.
Undermining
Another word for laceration -description is used for skull injuries where the force is applied causing a pocket to form under the skin but it does not create a flap as seen with avulsion.
Noxious gases
Carbon Monoxide -Cyanide -Hydrogen Sulfide
Cyanide
Colorless, but does have an odor of burned or bitter almonds -Detectable by 60-80% of people --Genetic trait
Choke holds
Mechanism of application is usually from the rear of the suspect -The upper arm is on one side, forearm is on other with the crook of the elbow in the front of the neck. -No longer used in law enforcement
Ecchymoses
superficial contusions commonly seen in elderly people -pink-brown
Report Documentation w guns
- Gunshot wounds documented by describing o Diameter of the wound, presence or absence of marginal abrasion, soot or stippling o General location of wound o Description of bullet and what it passes through o Site of recovery, exit wound description o Describe trajectories or wound descriptions from the decedents point of view
Revolver
- Hammer, trigger, cylinder, cylinder latch, grip, barrel and extractor rod - Can hold 5-6 bullets - Barrel usually 2-8 inches long - Longer the barrel, more accurate the bullet will be on its target
Sudden Death With No Cause Identified (Children)
- Not uncommon for findings in evaluation of infant or child death to not point to single cause or manner of death
Fetuses And Home Births
- Placenta will need to be obtained to determine fetal gestational age - Determine if live birth - Home births or discarded infants in an attempt to hide birth will be investigated by forensic pathologist - Questions asked by law enforcement include whether it was a live birth, age of viability, how long fetus/infant lived - Skeletal remains of infants can be difficult to find
Anatomy of a vehicle
- Seat belts - Car seats - Airbags - Tempered glass and laminated windshields - Pillars
Children Left In Vehicles
- Temperatures inside vehicle can raise to 120*F in 60 minutes if windows are closed - Document if child was restrained in a car seat and any signs of escape efforts - Presence of liquids or food - Children left in hot car may show early signs of decomposition change and will continue to rapidly decompose even though they are refrigerated at the morgue
Cartridge
- The complete "bullet" that contains the true lead bullet on the tip, with or without an overlying jacket, and a casing, which holds the gunpowder, primer, and bullet in alignment - Shotgun cartridge -- Plastic or paper cylinder containing multiple pellet projectiles -- Inside of barrel is smooth, leaves no markings are made -- Shotguns are extremely lethal -- Wadding or plastic piston will give indication of shotgun gauge
Bullet
- The lead portion of the cartridge that leaves the end of the barrel (muzzle) when the gun is fired. - As bullet exits barrel, burned and unburned gunpowder and hot gases are expelled into surrounding environment - Barrel's length, distance from victim, and amount and type of gunpowder will determine how much is seen on clothing and skin of victim
Casing
- The spent portion made of a cartridge that is discarded after firing. It is usually made of brass or steel and remains in the cylinder of revolvers or can be ejected to the side in semi-automatic weapons.
Barrel
- The tube that gives the projectile directionality and allows the gun to achieve its maximum velocity.
Guard ("Hilt") of knife
- a feature not seen in every knife and is derived from its counterpart in a sword - a dull piece of metal the projects at the right angles from the handle and blade and serves as a protective device preventing the hand from sliding down onto the blade during use.
Mechanical Asphyxia (Positional)
-More subtle and where the position of the body itself causes the impairment of oxygen exchange -Largely laying on diaphragm -A persons natural instinct is to move to side position -Impairment examples: alcohol/drugs, senility, or entrapment by obesity or weakness of the legs/arms --Reaching behind fridge and becoming entrapped.
Metabolic Disorders
-Most common are screened at birth and submitted to state health agency -Type 1 Diabetes -Fatty acid oxidative disorders inherited due to lack of enzyme in metabolic breakdown of fats --One of cause of death screened for in sudden death of an infant
Nonaccidental Trauma
-Patterned injuries abrasions matching belts, flyswatters, electrical cords, etc. help distinguish a nonaccidental cause of death from accidental injuries. -Burns from hair curling irons and hot water -Bruising or finger marks -Contusions on the abdomen -Loss of teeth or gum lacerations -Note caretaker history and how the child came to receive medical care. Is story plausible with the degree of injury? -Irons and curling irons- patterned burns -Bath tub- time it takes to reach scalding temp. -Penile and vaginal DNA swabs -Knees, elbows, chin, and forehead associated with falls not expected in immobile infants.
Public Health Notifications
-Pediatric infectious diseases need to be reported and the public health department needs to be notified -Family members or children in the home or school need to be treated to prevent an outbreak
Evidence Collection w guns
-Photographic documentation of each piece of evidence o Patient label, specific notation, date and time collected, two-dimensional ruler in photo -Bullets never collected using metal instruments o Collected using latex gloves, then wrapped, labeled, and sealed with seal dated, initialed, and timed
Suicide v accident
-Sometimes hard to determine - Scene findings are key -Presence/absence of the ligature and the pattern of its furrow on the neck also gives an indication of the course of events --Ligature absent: could've been removed by family or law enforcement --Pattern: horizontal- accident b/c homicide
Illness (SIDS)
-Stuffy nose, slightly decreased appetite, fussier than usual -Occasionally no change at all -Interval between symptoms and death may be short --Some children succumb to bacterial infections and sepsis rapidly
Grooves
-The depressed areas inside the gun barrel of a handgun or rifle that create the bullet markings on the projectile and allows guns to be matched to the recovered projectile.
Caliber
-The diameter measurement inside the barrel between two lands and is measured in millimeters for most weapons.
Hydrogen Sulfide
-Toilet and bathroom cleaners (acid) combined with bath salts, pesticides or detergents (bases) -Increasing trend for suicide
Neoplasms
-Undiagnosed neoplasms may cause death in children -Brain tumors, leukemias, bone/soft tissue tumors, solid tumors of internal organs
Strangulation
-homicidal strangulation may occur from a ligature or by arms and hands -- homicidal strangulations have a horizontal pattern -strangle: defined as to choke to death by compressing the throat with something such as hands or a rope.
Ejector
Each gun needs a method to extrude the expended bullet casing/cartridge and move the next active bullet into firing position.
Autopsy Procedure (SIDS)
More extensive for kids than adults -Total body x-ray (babygram) -Skeletal Surveys- healed fractures (helps find the difference between non accidental and accidental) -Body measurements are taken --Weight, length, head, chest, abdominal circumferences, crown to rump -- inches or centimeters -Cultures are collected --Bacterial- spinal fluid, blood, and lung --Nasopharyngeal swap for viral pathogens (couple hours) -Blood- heart blood -Slit in lung tissue- swab -Liver and brain tissue- common diseases -Evaluation of vessels entering and leaving heart -Gastric contents- toxicology testing -Any scalp injuries documented- absence of blood over surface or extreme swelling. -Neck, removal of tongue, evaluation of posterior pharynx is important to look for obstructions -Cavity is dried to evaluate inner surfaces of ribs -Spine can be removed to look for fractures -In non-accidental cases, dissection becomes more intense -Generally begins with skin dissection and only muscle layers left
Gauge
Reflects the diameter of the barrel of a shotgun and is determined by the umber of lead balls that can fit in the diameter of the shotgun barrel that equal 1 pound. -ex) 12-gaguge shotgun and the barrel diameter is .73mm, it would require 12 balls to make a pound.
Asphyxia
Results when a process causes a lack of oxygen to the brain, unconsciousness, and death -Common causes: hanging, strangulation, drowning, or mechanical causes like compression of the chest of positional asphyxia
Mechanical Asphyxia (Compression)
Results when some mechanical device compresses the chest or abdomen, inhibiting movement of the diaphragm and lack of oxygen/carbon dioxide gas exchange -Ex) motor vehicle accidents/ industrial accidents -abrasions, intense congestion, hemorrhages may be seen in the sclera (white part of eye)
Autopsy Documentation
Stab wounds deeper than they are long •Incised wounds commonly known as slashing injuries or incisions - longer than they are deep -Surgical incisions •Lacerations contain abraded margins, have small strands of tissue extending between the edges of the wound and tend to have irregular margins
Investigative Techniques (SIDS)
Sudden Infant Death Reporting Form -Each state has an infant death protocol checklist -Many times the child has been removed from the site of death during resuscitative efforts and will be pronounced dead at the hospital -Establish time child was found and time he/she was noted alive. What happened in between? -Crib, bedding, and any object in crib should be photographed and closely examined -Thermostat settings- room temp. -Scene reenactment- photos during each stage
Handgrip
The handle position of a handgun used to encircle the base of the gun for the hands to steady it for firing.
Positional asphyxia
The impairment of oxygen exchange caused by the position of the body.
Gunpowder
The material that creates the power behind propelling the bullet from the gun. There are three main types: cylinder, ball and flake. -Bal powder is smaller and more aerodynamic, allowing it to penetrate clothing and other intermediate targets much easier than flake powder, which has a greater surface area. Cylinder powder has intermediate properties
Trigger
The mechanism that fires the bullet from the chamber in all guns. Pulling it toward the handgrip will cause the trigger to be cocked and ready for release to fire the bullet.
Firing pin
The portion of the trigger that strikes the primer at the base of the bullet causing ignition of the gun powder. -Located on the tip of the hammer inside the firing chamber -Pattern created on the bullet casing base can also add info about the specific weapon.
Rimfire
The primer being located in a circular rim at the periphery of the base of the bullet casing.
Centerfire
The primer being located in the center position at the base of the bullet casing.
Lands
The raised portions of the rifling inside the barrel of a gun that create markings on the soft lead bullet as it travels down the barrel. -Gun specific markings, allow a projectile to be matched to a particular rifle weapon.
Shot
The round balls compsing the lead portion of a shotgun shell. These can vary in size from 9.14 mm to 1.3mm. -In general, the larger the number- the smaller the size of the ball
Rifling
The spiraled tooling inside the barrel of a rifle or handgun that puts a spin on the bullet projectile and is gun specific. The gun barrel is created from a tube of steel that is then made into grooves that'll vary in spacing and depth. -Most guns have a right-twisting spiral as viewed from the shooters perspective. -Colt handguns are left twisted
Anoxia
The total lack of oxygen
Stock
The wooden or plastic portion of a rifle or shotgun used to steady the gun against the shoulder during firing.
Food (SIDS)
Type of food the child ate last, amount of formula, time of last feeding all important -Undernourished? -How formula mixed and volume -How often fed and natural or solid foods -Quantity and type of stools
Fractures
• Amount of force needed depends on the bone, age of the individual, presence or absence of underlying disease affecting strength of bone • Skull fractures may be linear (line fracture with edged abutting against each other) or depressed (bone pressed inward and tears underlying brain tissue)
Car Seats
•1978 - Tennessee first state to require child car seat use •All states require children 3 or younger weighing less than 40 pounds and less than 40 inches tall be secured while traveling
Collection of Evidence (Sharp-Force)
•A sturdy box is useful for transporting •Blade and handle need to be protected -Blood traces, fingerprints •Blood can become entrapped in tiles, baseboards near floors, behind doorknobs, and various other cracks •Documentation of clothes includes laying out each item and demonstrating knife injuries through the surfaces if present •Knife should not be removed from the body prior to being examined by a physician
Skid Marks
•Black marks left on pavement when brakes are suddenly applied and the vehicle is still moving •Length of skid marks to site of impact helps determine how fast vehicle was moving at the time of the accident •KE=1/2MV2 •Kinetic energy = ½ mass times velocity squared
Death Certification and Report Writing
•Date, time of accident, location of accident, circumstances surrounding death, time of death •Behavior before accident and details of how individual was found •Decedents are not necessarily dead by what would seem the obvious case
Documentation of Injuries
•Direct visualization with collection of trace evidence •Patterned injuries need accurate descriptions •Photographs include overalls, medium view, close ups with and without a scale •Angles need to be accurate to avoid distortion to wound measurements
Passenger/Occupant
•Fewer patterned injuries than drivers •Front seat passengers may suffer from airbag injuries if there was a front end impact •Back seat passengers may suffer from right or left side dicing wounds and shoulder harness abrasions
tempered glass and laminated windshields
•Front glass composed of two thin sheets of glass laminated over a piece of clear plastic •Site of impact will cause glass to fracture in a radiating pattern •Side and rear windows are tempered glass designed to shatter into 1/8 to ½ inch irregular shards of glass •Pieces cut the skin and can help determine the position of the occupant
Airbags
•Late 1980s and early 1990s •Upon sensors being triggered airbag will deploy •If vehicle collides with an object at an angle where sensors are not triggered, airbag will not deploy
Other Instruments
•Machetes, scissors, ice picks, forks, etc. •May appear more as punctures or have chop wound qualities •Chopping wounds from hatchets, swords, axes will show qualities of both sharp and blunt impacts
Measurements for Sharp-Force
•Measures in length, width, depth •Wound can be longer than the width of the blade due to cutting motion •Width of wound corresponds to thickness of blade •Length of wound will vary due to cutting as blade is inserted or withdrawn •Depth of wound is a rough estimate of the length of the blade •Incised wounds are commonly known as slashing injuries or cuts •Incised wounds commonly long -Incised wounds commonly known as slashing injuries or cuts -Longer than they are deep •Incised wounds present on anterior wrists, antecubital fossae, and isolated neck raise a question of self intent •Hesitation wounds •Serrated blades are sometimes used and depth of wound will show no distinction from smooth edged knife
Motor Vehicle Accidents
•Most common cause of blunt-force trauma •Collection of evidence on pedestrian hit and run accidents help link a suspect vehicle to decedent •Relevant scene observations include - seatbelt use - position of body - air bag deployment - Tempered glass and laminate windshields
Manner of Death (Sharp-Force)
•Most common from sharp force injuries is suicide or homicide •Suicide -Notes, evidence of preparation, history of depression •Homicide -Blood trails through crime scene, someone found outside, lack of depression
Patterned Injuries and tool marks
•Patterns used to reconstruct how injuries occurred •Can trace patterns onto clear plastic •Toolmarks can leave grooves that can be matched to suspect weapons
Pillars
•Posts supporting the roof •'A' pillar nearest the hood, surrounding windshield at the front of the doors •'B' pillar behind driver and front passenger doors supporting mid region of roof •'C' pillar surrounds rear window or rear door in a hatchback
Surgical Incision
•Same appearance as many stab wounds •Medical personnel need to adequately document any changes made to skin during resuscitation •Medical intervention should avoid sites of previous stab or gunshot injuries -Forensic pathologist can adequately evaluate wounds in the event of patients death
Hesitation Wounds
•Testing of the sharpness of the blade •How much pain is required with cutting prior to fatal wound being inflicted •Common locations are wrists, forearms, abdomen, neck •Locations and number of superficial wounds help distinguish hesitation wounds from defense wounds
Seat Belts
•Two point restraint system - Lap belts with two attachment points to the vehicle •Three point restraint system - Two lap belt attachments and one shoulder attachment - Typical in modern vehicles •Four point restraint system - Two shoulder attachments and two lap attachments - Race cars, pilot seats of airplanes •88% of people wear seatbelts in primary enforcement states •75% of people wear seatbelts in secondary enforcement states •In an accident the webbing will stretch and leave wrinkles along area of greatest stretch, telling investigator whether or not the seatbelt was in use
Trains
•Two types of deaths: one involving a person within a vehicle, one involving a pedestrian •Injuries are usually extensive whether pedestrian or inside vehicle •Engineers help determine amount of time it takes to stop train •Train accidents require urgency because trains are stopped both directions until investigation is complete
Pedestrians
•Upon contact with a vehicle, there can be a transfer of hair, fluids, car paint, plastic particles, etc. •Children will usually be carried in the front of a vehicle until it slows and then fall to the ground •Adults hit at speeds under 35 mph will fracture his or her legs, slide onto the hood and hit the windshield •Adults hit at speeds over 35 mph will fracture his or her legs and be lifted to the roof of the vehicle and may fly over the top to drop on the pavement •Injuries peculiar to pedestrians are leg bumper injuries and grill injuries
Coup vs. contrcoup
•Used when referring to head injuries •Coup injuries = force applied to one side of the head resulting in same sided brain injuries, with or without skull fractures •Contrecoup injuries = injury on one side of the scalp and brain injuries on the opposite side
Cause of Death (Sharp-Force)
•Usual mechanism of death is blood loss •Death is not immediate with stab wounds, number of wounds inflicted usually increase as victim fights back or keeps moving •Air embolus •Examination of suspects include photos of arms and hands to demonstrate any injuries during confrontation
Work/Farm Related
•Usually involve a piece of machinery, electrical malfunction, or natural disease •Clothing is important to document - Loose clothing can become tangled in machinery •Gloves, helmets, shoes, and safety harness use also important to note