che 113 exam 2
post-mortem interval
Elapsed time from a death to the discovery of a cadaver. Flies (especially calliphorids and sarcophagids) can be vital in determining the PMI Premises: Flies will begin oviposition as soon as they discover a body, Succession on a corpse is predictable, Insect development is predictable
paint analysis
Lincolnshire, UK - 1991-1993, two murders by axe. nImprint of axe found on sofa and pillows axe found in local pond and paint analysis by ICP-AES matches paint at crime scene axe shape matches patterns found on sofa.
blood
circulatory system and is continually being pumped distributes oxygen and nutrients, removes wastes (exhalation), others to the kidney and liver for processing and elimination mixture of cells and plasma
projected bloodstains
created when a blood source is subjected to an action greater than the force of gravity the size, shape, and number of resulting stains will depend on the amount of force utilized to strike the blood source
postmortem
after death
hair growth
anagen - up to 6 years, length of anagen determines maximum hair length catagen - usually up to several weeks telogen - up to 6 months animals that shed synchronize the telogen phases hair growth fairly uniformly at .5mm/day
crowner
ancient, king's representative for examining deaths
perimortem
at or around the time of death
decomposition
autolysis - normal internal process putrefaction - bacterial decomposition - various stages (fresh, bloated, etc) insects and animal action
automated fingerprint identity system
automated scanning devices integrated automated fingerprint identification system (IAFIS) next generation identification (NGI)
forensic blood analysis
blood id (is it blood?) blood origin (human or other source) blood type blood spatter analysis
projected bloodstain - cast-off stains
blood released or thrown from a blood-soaked object in motion
projected bloodstain - impact spatter
blood stain patterns created when a blood source receives a blow or force resulting in the random dispersion of smaller drops of blood
dripping blood
blood trickles downwards blood drop grows until Wt (G) > S.T. single drop breaks free (teardrop shape) surface tension pulls in vertically and horizontally shape settles into sphere does not break up until impact
specific types of antigens on our red blood cells determine...
blood types (only 27 known)
forward spatter
blood which travels in the same direction as the source of energy or force which caused the spatter
projected bloodstain - arterial spurt/gush
bloodstain pattern from blood spurt under pressure from a cut artery
duties of the medical examiner
document and interpret injuries and diseases collect evidence estimate postmortem interval determine and certify the cause and manner of death authorize cremation (50%) and organ and tissue donation requests testify in court
passive bloodstains
drops created or formed solely by the force of gravity can be subdivided into drops, drip patterns, pools, and clots
natural
due to disease, illness, or pathology
uses of forensic ecology
estimations of postmortem interval (PMI) - time elapsed between the discovery of remains and the actual death of the organism locating human remains and determining whether the remains have been moved (differentiate burial from death sites) determining relationships between people and places (e.g., has a person recently visited a particular site) determining if a crime site has been disturbed (e.g., has something been hidden, removed, changed, or been buried at a given place and when these changes occurred) validating or disproving disputed events (e.g., has a person lain or kneeled on a particular patch of ground or what did someone last eat as determined from plant remains in the stomach) recreating a timeline of events in a crime commission
common types of trauma
firearm injuries drowning/aspyxia blunt force trauma sharp force trauma vehicular trauma fire-related deaths sudden and unexplained deaths
livor mortis (lividity)
gravity causes blood to settle in vessels 1-2 hours color changes in skin pressure changes color early on (blanching) blanching halts 8-12 hours
blood id - is it blood?
hemoglobin has peroxidase-like activity (enzymes that accelerate oxidation of organic compounds)
blood chemistry
hemoglobin is a protein containing heme groups
primary classification
henry (fbi) system - all prints fall into one of 1024 groups pair up fingers o hands determine whorls - list numerical 10 finger system
polyethylene
high density polyethylene (HDPE): staright chain polymer - chains "pack" together tightly like a crystal - high density, high strength, high mp low density polyethylene (LDPE) - branched chain polymer - side groups impede "packing" of the chains - low density, low strength, low mp
how old is it?
historic versus forensically location and context co-burial items condition
5 critical questions for bones
is it bone? is it human bone? how old is it? whose bone is it? how did they die?
AFIS
law enforcement agencies, such as the fbi and the scotland yard, have built up vast collections of fingerprints a fingerprint is first classified and compared with filed prints to try and establish a match, and therefore to identify a possible suspect
benzidine color test
previously used but dropped due to carcinogenic reagents
cuticle
scales on exterior of hair shaft - keratinized
whose bones are they?
sex age stature trauma pathologies hip bone is most useful for adults teeth: erupted or not? epiphyses: fused or unfused?
proxy indicators
small amounts of identifiable material from an ecosystem that can indicate with relatively high accuracy information about the entire ecosystem from which they originated
satellite spatter
small droplets of blood that are distributed around a drop or pool of blood as a result of the blood impacting the target surface
forensic botany
study of plant life: 400,000 known species and biggest (1.3 million lb) and among smallest life-forms (1 mm) uses of forensic botany (1) tracking a suspect's or victim's movements, (2) validating alibis and proposed timelines of events, (3) determining how long someone has been dead, (4) dealing with issues of plant-based poisons and toxicology, 5) deciding on whether a particular wooden tool has been used for a particular purpose, (6) investigating food adulteration cases
osteology
study of skeletal remains - each bone studied individually human bone versus animal bone macroscopic differences - radiology, observation, measurement microscopic differences
forensic pathologist
subspecialty of pathology that deals with death investigations
antigen
substance that can trigger an immune response, resulting in production of an antibody as part of the body's defense against infection and disease
immunoassay
technique utilizing antibodies to bind specifically to targeted substances in a specimen in order to identify their presence
spatter
that blood which has been dispersed as a result of force applied to a source of blood. Patterns produced are often characteristics of the nature of the forces which created them
red blood cell uniqueness
strange shape--- a biconcave disc, round and flat, like a shallow bowl no nucleus, the nucleus is extruded when cell matures change shape without breaking as it squeezes single file through the capillaries contains hemoglobin, a molecule specially designed to hold oxygen and carry it to cells that need it
zoology
study of animal life
entomology
study of insect life
botany
study of pant life
plasma function
liquid portion of the blood containing electrolytes, nutrients, waste products, vitamins, hormones, clotting factors, and proteins such as albumin and immunoglobulins (antibodies to fight infection)
stature
long bones are best measurements and use formula
projected bloodstain - impact types
low velocity - gravitational pull up to 5 feet/sec, relatively large stains 4mm and greater medium velocity - force os 5 to 25 feet/sec, stain size 1mm to 4mm high velocity - force of 100 feet/sec and greater, stain size 1mm and smaller
cause of death
medical diagnosis denoting disease or injury proximate cause of death - initial injury that leads to sequence of events which cause death immediate cause of death - injury/disease that finally kills a person manner of death - intent or seres of events that brought bout the death
hair structures
medulla vary from person to person and even among hairs from one person 3 main medulla types: continuous, interrupted, and fragmented growth phases - anagen: initial phase where hair actively grows - catagen: transition between active and loss stage--- slowed growth - telogen: final phase resulting in hair loss
death examined by medical examiner
no doctor available to sign death certificate violence sudden of unexpected threat to public health prisoner or in a prison suspicious, unusual, or unnatural related to an occupation related to medical procedure (medical misadventure)
red blood cells aka erythrocytes
most abundant cells in the blood gives it characteristic red color 5M RBCs per cubic microliter 40%-45% of the blood blood percentage is measured and called the hematocrit---the ratio of cells in normal blood is 600 RBCs for each white blood cell and 40 platelets
forensic ecology
natural world companions; animals, plants, fungi, protists, bacteria and others studying organisms and their environments and using these relationships to look for observable changes or patterns that can provide unique legal information habitat: climate, non-living components, light conditions
type o
neither protein is present
antigens
on blood cell surface type a - only the a protein is present type b - only the b protein is present type ab - both proteins are present type o - neither protein is present
preserving prints
photography (analog and digital imaging) lifting with tape
liquid blood
physical properties: viscosity, surface tension, specific gravity behaves as a projectile in motion: biology, physics, math
synthetic polymer characteristics
plastic - capable of being molded polymer - large, high molecular weight molecule formed by joining together a large number of molecules of low molecular weight first synthetic plastic - 1870 - answer to contest to make artificial billiard balls plastics - now they fit needs that NO other materials can fit from artificial skin to high strength composites
plastic properties
plastics have an enormous range of properties, from soft and opaque to very hard and transparent the features which account for these range of properties are: - length of chain - 3D arrangement of chains - branching of chain - composition of monomer units - bonding BETWEEN chains - orientation of monomer units WITHIN chain
blood clotting
platelets (thrombocytes) help blood clot by forming a platelet plug, blood clots, or other mechanisms
biopolymers
polymer - large, high molecular weight molecule formed by joining together a large number of molecules of low molecular weight proteins - formed from amino acids carbohydrates - polyhydroxy aldehydes and ketones nucleic acids - complex high molecular weight biopolymers
time of death - body temperature
postmortem body temperature drops ca. 1.5ºF per hour (normal conditions - slower in cold conditions) faster in water affected by wind and insulation initial temperature may be abnormal altering calculation (fever) may rise in hot environments
blood spatter analysis
the examination of the shapes, locations, and distribution patterns of bloodstains, in order to provide an interpretation of the physical events which gave rise to their origin
forensic anthropology provides critical answers by understanding...
the structure and function of the bones of the human body how to determine if an object is bone or not how to determine if a bone is human bone how to determine how old a bone is how to construct a biological profile from skeletal remains how to prepare a facial reconstruction from a skull how to gain insight into how someone died by examining their bones how to process a crime scene contain bones what is forensic taphonomy
katle-meyer test
uses phenolphthalein blood + phenolphthalein + H2O2 yields a deep pink color can give false positives
death investigator
usually non-MD but highly trained and experienced
undetermined
when a classification cannot be reasonably made therapeutic complications: death occurred due to known and often predictable side-effects from appropriate medical procedures; misapplication of standard medical practice are not part of this category well-intentioned mistakes, including incorrect diagnoses, lead to death: these are properly classified as arising from a natural manner of death
blood origin - human or other source - precipitin test
when animals are injected with human blood they form antibodies to the human blood can isolate human antiserum (antibodies to human blood). human antiserum will react only with human blood antiserum can (has) been made similarly for many other animals works on old (dried for many years) and small samples of blood.
blood clots
when blood vessels are cut or damaged, the loss of blood from the system must be stopped before shock and possible death occur accomplished by solidification of the blood - a process called coagulation or clotting a blood clot consists of a plug of platelets enmeshed in a network of insoluble fibrin molecules
when?
when were you hurt? aging injures: gross inspection, color, texture contusions (bruise - color change such as purple/blue to yellow/brown to yellow/green), microscopic, inflammation, repair when did you die? rigor mortis, lividity, temperature
where?
where were you hurt? where did you die? taphonomy investigation of the scene and circumstances forensic pathologists usually do not make house calls record reviews - paramedics and hospital inconsistencies between findings at the scene and otehr data - autopsy
the case of the wills west 1903
1892 - english scientist Sir Francis Galton published a book entitled Finger Prints in which was laid out a method of classification of fingerprints 1897 - Indian Police officer Sir Edward Henry proposed a modified classification system which was adopted by Scotland Yard in 1901 -still the basis of the systems used in most English speaking countries 1901 - First official use of fingerprints in the USA by the New York City Civil Service Commission 1930 National fingerprint file set up in America by the FBI
cobbler's basement
1942 - Cincinnati Cobbler accused of murder of young girl in basement basement excavated and 18 bones found and a bunch of ribs incriminated cobbler - several other murders in area unsolved bone from: cow, five sheep, a turkey or goose, a rat, a pigeon, and an owl - none were found to be human
forensic fiber analysis
1979 to 1981: more than 25 males strangled, bludgeoned or asphyxiated the only clue was several of the bodies of fiber threads and a few also had strands of dog hair fibers were two distinct types: a violet-colored acetate fiber and a coarse yellow-green nylon fiber associated with carpets stakeout of river dumping ground: stakeout patrol heard a loud splash and stopped a white Chevrolet station wagon driven by Wayne Williams police searched Wayne Williams' home and found floors of Williams' home were covered with yellow-green carpeting, and he also had a dog comparisons from the samples removed from the victims showed good consistency with Williams' carpet
types of prints
latent prints visible prints plastic prints
loops
1 or more ridges entering from the side of the print, recurving and exiting from the same side opens toward little finger its ulnar and toward thumb it's radial pattern area surrounding the loop is a type line delta surrounded by type lines all loops have at least 1 delta
blood loss
40% blood volume loss, internally and/or externally, is required to produce irreversible shock (death) blood loss of 1.5 liters, internally or externally, is required to cause incapacitation
blood volume
8% of body weight 5-6 liters for males 4-5 liters for females
blood type - 3 ways
ABO and Rh testing additional blood groupings enzyme presence
steps of autopsy
External Examination Y-Incision Internal Examination Removal of the Brain Weighting the Organs Examination of Stomach and GI Tract Sample Collection Return Organs to Body Sew Up Y-Incision
back spatter
blood directed back towards the source of energy or force that caused the spatter
stages of decomposition
Fresh Stage (Days 1-2): Commences at death, ends when bloating is first evident. Breakdown of protein and carbohydrates into simpler compounds Bloated Stage (Day 2-6): Putrefaction begins. Gasses produced by anaerobic bacteria inflate the abdomen. Decay Stage (Days 5-11): Abdominal wall breaks - gasses escape - carcass deflates. Post-decay Stage (Days 10-25): In dry habitats, remains are skin, cartilage, and bones. In wet habitats, wet, viscous material in the soil under the remains. Dry Stage (Days 25+): Mainly bones and hair remain. Odor is primarily that of normal soil and litter. Can last several months to years.
forensic anthropology includes...
General Description Sex of decedent Age of decedent Ancestry of decedent Stature of decedent Assessment of trauma (ante-, peri-, post mortem) Pathologies noted
luminol test
Rx of luminol with blood produces a complex which can be seen by luminescence very sensitive - up to a 3,000,000 dilution of blood can be seen detects unseen samples and patterns does not interfere with later DNA testing
how an autopsy is performed
Step 1 - Access and Control of the Remains: Step 2 - External Examination: Step 3 - Opening the Thoracoabdominal (thorax and abdomen) and Brain Cavities: Step 4 - Removing Organs: Step 5 - Evaluation and Analysis of Sample: Step 6 - Closure:
the start of synthetic polymers
Wallace Carothers invented nylon and neoprene in a single creative burst in the early 1930's the inventor led us into the synthetic age, bringing synthetic rubber and fiber to DuPont and the world but Carothers was a troubled man which led to his inevitable fate -- suicide at the age of 41 - by a powerful combination of depression and alcoholism a biography of Carothers (Enough for One Lifetime) tells his story against the backdrop of the Depression
blood types
a blood group or blood type is based on the presence or absence of 2 proteins on the surface of red blood cells
transfer bloodstains
a transfer bloodstain is created when a wet, bloody surface comes in contact with another surface occasionally, a recognizable image of the original surface may be observed in the pattern, such as a hand or shoe pattern subdivided into Contact bleeding, Swipe or Smear, Wipe, and Smudge
mechanism of death
altered physiology by which disease/injury produces death (arrhythmia, exsanguination)
proteins
amino acids are linked by amide groups called the peptide bond form shapes such as helicies and sheets--- hydrogen bonds are weak electrostatic bonds between H and O
when an autopsy is performed
any unattended or unexplained death when a physician is not available or willing to sign a death certificate; any unexpected death that takes place under unusual, unexplained, or suspicious circumstances suggesting foul play; any death resulting from homicide, suicide, or certain types of accidents; any death that could pose a risk to the public health; any death that takes place while the person is in legal custody; any employment or occupational-related death; any death of an institutionalized person for reasons other than illness; any death from a standard "lower-risk" medical procedure; any hospital death when the person is pronounced dead on arrival or occurring within the first 24 hours of being admitted unconscious; any death that appears to be the delayed result of a previous injury, especially when the injury resulted from criminal actions; any death where the body will be cremated
hair - class evidence
appendage of the skin that grows from a follicle resistant to chemical decomposition and long term structural stability can often determine body area where the hair originated and sex of owner can occasionally determine racial origin (anthropology terms) negroid: often kinky with dense uneven pigment flat to oval in shape caucasoid: often straight or wavy, fairly evenly distributed pigment, oval to round shape
medical examiner
appointed by government, licensed MD or DO
medicolegal investigations
assigns responsibility regarding the causation of an injury or ailment abuse and human rights Issues liability cases (e.g., drug interactions, malpractice medical "misadventure", etc.) patient rights protection, advance healthcare directives clinical pathology (e.g., non-accidental injury, abuse, assault, and rape), describe cause, severity, description, etc. mental competence death investigations: focus of this chapter.
the cuticle and medulla are...
best used tp distinguish if the sample is animal or human
natural polymers
biopolymers, proteins, polysaccharides, nucleic acids, and others such as spider's web, wool, asbestos, graphite, etc...
two types of blood evidence
blood biochemistry analysis and pattern analysis
type ab
both proteins are present
time of death
can estimate the time of death from: body temperature (algor mortis), estimate: 98.6 - rectal temp/1.5 rigor mortis (temperature dependent, muscle fibers become cross-linked and fused/ATP depletion, muscles stiffen/not contract, first noticed 2-4 hours postmortem, max 8-12 hours and remains 12-24 hours insect action - forensic entomology stomach content - stage of digestion last known activity - last sighting or the newspaper/mail normal postmortem changes
algor mortis
can estimate time of death from body temperature muscle fibers become cross-linked and fused ATP depletion muscles stiffen/not contract first noticed 2-4 hours postmortem max onset 8-12 hours remains 12-24 hours
determinations of manner of death
can it be changed? when and how? criminal injury related?
dusting
carbon metal magnetic powders
4 broad determinations to be made by a forensic pathologist
cause of death mechanism of death manner of death time of death
plasma characteristics
clear, yellowish fluid, sometimes appear milky after a very fatty meal or when people have a high level of lipids in their blood 90% water and the rest is protein blood that is allowed to clot and then filtered is blood serum--- contains none of the clotting factors
contusions
color changes a bruise goes through can give rough estimate of time of injury dark blue/purple (1-18 hours) blue/brown (~1 to 2days) green (~ 2 to 3 days) yellow (~3 to 7 days) assumes person is healthy
when comparing hair...
color, length, and diameter are important
ninhydrin method
colorless compound reacts with amino acids in sweat to form a colored compound
bullet wounds
contact wound: muzzle applied to skin at shooting. Impression of muzzle burned around entrance wound and absence of fouling and stippling contact wounds over skull have stellate appearance from expulsion of hot gases from barrel blowing back toward exterior rip apart skin around entrance wound close range (6-8 inches): entrance surrounded by fouling- soot traveling for short distance; stippling intermediate Range (1.5- 3.5 ft.): No fouling; hot fragments of burning gunpowder; "ball" and "fake"stippling at entrance wound distant (greater than 3.5 ft.): No soot or burning propellant; clean wound margins entrance wound: rim of abrasion dragging surrounding skin exit wound: projectile penetrates skin and pushes in outward
visualizing prints - superglue
cyanoacrylate ester when vapors come into contact with fingerprints the molecules of the cyanoacrylate attach to the print and polymerize the visible prints produced are white, but are often treated with a fluorescent dye to improve visibility
suicide
death brought about intentionally by the person who dies themselves in an effort to end their own lives
homicide
death caused by another individual, whether by intent, through negligent actions, or inadvertently differentiate between the level of intent used to bring about someone's death: on purpose - murder and homicide charges and without intent - leading to manslaughter charges
forensic anthropology
defined as "the field of study that deals with the analysis of human skeletal remains resulting from unexplained deaths." often done in a legal context an applied science five subdisciplines: 1. Biological, or physical anthropology 2. Archaeology 3. Cultural anthropology 4. Linguistics 5. Applied anthropology
medulla
either absent or ca. 1/3 the diameter of the shaft continuous, interrupted, segmented, or absent
coroner
elected official, may have no medical experience
hair is best identified by...
examining the medulla and cuticle
luminescence
excitation of a molecule can happen in several ways including absorption of light or as a result of a chemical reaction an excited molecule will lose energy with the electron falling back down the energy staircase to the ground state for some molecules the excess energy is lost in the form of light, it is this process that is known as luminescence a common application of luminescence is washing powder that contains optical brightener the optical brightener is a fluorescent dye that shows a blue luminescence when excited by the ultraviolet radiation present in sunlight luminescence is used forensically to detect fingerprints, it also found application in de-bunking the fake Hitler diaries some components of sweat are luminescent and fluoresce when illuminated with lasers and also, fluorescent dyes can be employed that do not require laser excitation.
MRI disadvantages
expensive
forensic mycology
explain cause of death from poisons and toxins help determine the location and time of death ties person or evidence to a particular place
fingerprints
form by contact of friction ridges on hands, feet, or lips with an object friction ridges assist in our ability to grasp and hold onto objects - approximately 2,700 ridge "units" per square inch of friction skin pore openings present on surface id the friction ridges fingerprints formed underneath the skin in the dermal papilae and as long as that layer is there, fingerprints will always come back
manner of death
homicide, suicide, accidental, natural, undetermined
types of genotypes
iAiA or iAi - Both genotypes produce the A protein (type A) iBiB or iBi - Both genotypes produce the B protein (type B) iAiB - This genotype produces the A and B protein (type AB) ii - This genotype produces no protein (type O)
biometrics
identification of humans by measurable physical traits
MRI advantages
images soft tissues (only those with hydrogen atoms (almost all "soft" tissues). images function through the use of contrast media
plastic prints
impressions of fingerprints in soft media
antibodies
in the blood type a - b antibody is present type b - a antibody is present type ab - neither a nor b antibodies present type o - both a and b are present
cause of death includes...
injuries always take precedence over disease for determining the cause of death includes things like blunt-force trauma, sharp force trauma, drowning (asphyxia), etc.
asphyxia and strangulation
insufficient amounts of oxygen reaching brain or essential organs of body natural diseases can shut down respiratory Emphysema, pneumonia, flu, asthma, larynx disorders asphyxiate causes of asphyxiation: drowning and smothering strangulation: homicidal, suicidal, accidental homicidal strangulation done manually- brute force choking around neck homicidal strangulation by ligature using rope, wire, or garrote hanging victim dies from pressure of body weight or neck breaks
latent prints
invisible to the naked eye and must be developed to see
visualizing prints - iodine
iodine sublimes at room temperature if an object is placed in a chamber with crystals of iodine placed in it, any fingerprints on the object will appear as brownish prints the iodine is believed to dissolve in the skin oils that make up the print (temporary and will fade)
wayne williams
key suspect in the Atlanta Child Murders in January 1982, he was found guilty of the murder of two adult men after his conviction, the Atlanta police declared an additional 22 of the 29 child murders solved hairs and fibers on one of the victims' bodies were found consistent with those from Williams' home, car, and dog
types of wounds - trauma
lacerations incised wound puncture abrasion contusion gunshot
cortex
main body of hair shaft, contains pigment granules, shape
is it bone? is it human bone?
microscopic macroscopic anatomy
visualizing fingerprints
most important method of detecting latent prints is to dust using a fine powder that adheres to the traces of oil and sweat aluminum dust, which is grey and highly visible on dark and mirrored surfaces carbon black for white surfaces luminescent powders which fluoresce under ultraviolet light magnetic powders other colors are available. dusting is suitable for hard and/or non-absorbent surfaces, for porous surfaces like paper or cloth another approach is needed
autopsy
not everybody needs autopsy not all are complete autopsies
a fingerprint is an individual characteristic
not the shape of the print that is individual, but rather the number, location and shape of specific ridge characteristics (also known as minutiae) courts often require 14-16 matched minutiae for a positive match will remain unchanged during an individual's lifetime fingerprints have general ridge patterns that permit them to be systematically classified
Karl Landtseiner 1900
noted that when blood from different people is mixed it sometimes forms precipitate--- deadly if mixed in body
type a
only the a protein is present
type b
only the b protein is present
synthetic polymers
organic polymers synthesized from organic monomers
blood stain evidence may reveal
origin(s) of bloodstain distance of bloodstain from target direction from which blood impacted speed with which blood left its source position of victim & assailant movement of victim & assailant number of blows/shots
blood in the veins
oxygen-poor it has unloaded its oxygen to the body's cells (exchanging O2 for CO2) and must now return to the lungs to replenish the supply of oxygen oxygenated: red deoxygenated: very dark red
white blood cells aka leukocytes
part of the immune system and fights infection circulate in blood to be transported to an infection site when WBCs increase, it is a sign of infection in the body
bloodstains
patterns created by same volume of blood, from same source to target distance
antemortem
prior to death
antibody
protein produced by the immune system of humans and higher animals in response to the presence of a specific antigen
blood's cellular components
red blood cells yellow platelets t-lymphocyte is light green
cellular portion of blood
red blood cells, white blood cells, and platelets
surface tension
resistance to penetration and separation surface acts to reduce surface area smallest surface area to volume ratio is offered by sphere
drowning
results from inhalation of water causing choking rapid formation of mucus in throat and windpipe "Foam cone" covers mouth and nostrils of drowned victims "Dry drowning" occurs from shock and enlargement of larynx. No fluids found in lungs or stomach Classic Drowning Stages: Surprise- person stunned and inhales water Holding breath- Person holds breath while struggling Pink foam- Inhales deeply and pink foam expelled Respiratory arrest- Thoracic movement and pupils dilate Final Struggle- 3-4 quick attempts to breathe and find air
Rh factor
rhesus monkey where it was first identified either present + or absent - o+, a+, ab-
normal postmortem changes
rigor mortis livor mortis desiccation putrefaction autolysis
burn and blunt force wounds
scorching or burning of skin leads to sepsis and is immediate cause of death wounds caused by heat, chemicals, or electricity fire victims found in "pugilistic" position: clenched fists, resembling pose of boxer heat causes protein in body to contract blood and lung samples taken blunt Force trauma results from clubbing, kicking, or hitting the victims the blow produces a crushing effect on the human body, resulting in contusions, abrasions, lacerations, fractures, or rupture of vital organs. red-blue contusions are always present, but this varies by the weight of the individual (obese people bruise easier than lean people)
fiber analysis non-hair
synthetic or natural (plant and mineral) polymeric characteristics: color, diameter, birefringence, shape, presence or absence of delustering particles rayon: classified as regenerated fiber (derived from natural material-cellulose), first man-made fiber 1911
angle of impact
the acute angle formed between the direction of a blood drop and the plane of the surface that it strikes
agglutination
the antibodies glue together the antigens from different red cells thereby sticking the red cells together forming "islands" blood mostly remains liquid with clotting, however, it does not remain a liquid
biometrics and key indicators
the application of statistical methods to biological data, is based upon finding some individualized trait that a person has that can distinguish them from all others universality uniqueness permanence measurability ease of use
trypanosoma brucei protozoa
the cause of african sleeping sickness
mycology
the study of fungi
palynology
the study of pollen, spores and similar materials along with the organic matter and traces of rocks and soils
soils and sediments
the study of the organic and inorganic matter found in soils and rocks
postmortem interval (pms)
the time between the actual death and finding the body
gunshot wounds
things for pathologist to learn: type of firearm distance of gun to victim entrance vs exit wounds track of projectile stippling - powder burns on the skin when the gun is inches to a few feet from the victim
blood type genetics
three forms of the gene (alleles) that control the ABO blood group, designated as iA, iB, and i two alleles (one from the mother and one from the father) form a persons genotype the inheritance of the alleles is co-dominant - if the allele is present, it gets expressed blood type does not necessarily tell you which alleles you have. It is possible for two parents with the same blood type (A or B) to have a child with type O blood both parents would have to have a mixed geno
type o-
universal donor has no protein to cause clumps or coagulation
type ab+
universal receiver the recipient has all of the proteins and will not forms clumps or coagulation
accidental
violent, unexpected death that was not caused by any intentional or criminal act by another person
HIV
virus that causes AIDS and infects white blood cells
who are you?
visual ID by friends or family ID cards and papers physical traits including scars and tattoos radiographic comparison fingerprint comparison dental comparison DNA testing
MRI - magnetic resonance scecptroscopy nmr
visualize soft tissue by measuring proton (nuclear) magnetic alignments relative to an external magnetic field
six critical questions of a body
who are you? when did you become ill? when were you hurt? when did you die? where did you get hurt? where did you die? did you die as a result of violence, natural causes, or a combination of both? if violence was completely or partially responsible for your death, was it suicide, accident, homicide, or undetermined? if someone killed you, who did it?
biomedical imaging
x-ray ultrasound CT MRI
forensic fingerprints
your fingerprint patterns are hereditary they are formed before a person is born they are unique and they never change gloves don't necessarily stop fingerprints prints can be left through surgical gloves gloves can also be turned inside out to yield fingerprints from the inside surfaces leather gloves leave prints that are unique to that glove and no other - leather comes from cow skin, sim. to human skin) even cloth gloves, such as mittens, can leave a distinctive print that can be traced back to the mitten that made it
