Forensic Medicine HOSA state test

subpoena

when a scientist is required to testify, this is sent to them stating when and where the trial is to be held

voir dire

the prosecution introduces a scientist as an expert and then describes their qualifications, training, background etc.

admissible evidence

evidence that is determined to be admitted into evidence and be considered in rendering the decision

inculpatory evidence

evidence that tends to implicate the accused party

exculpatory evidence

evidence that tends to free from guilt the accused party

direct evidence

info that establishes a fact directly with out the need for further inference. ex-eyewitness testimony that the defendant fired the fatal shot

circumstantial evidence

evidence requiring the trier of fact to infer certain events. ex-linking a defendant to a crime scene via DNA, hair, fiber, footprint etc.

reconstruction evidence

evidence of the events leading to, occurring during, and occurring after a crime is committed

association evidence

establishes a relationship between objects. ex-glass, hairs, bullets, fingerprints

class characteristic

evidence that does not reference a particular suspect

individual characteristics

associate a particular individual with the commission of a crime

trace evidence

whenever two objects come in contact with each other a transfer of material will occur

first responding officers

usually police officers, fire department, emergency medical personnel. Their actions at the crime scene will form the basis for successful or unsuccessful resolution of the investigation

the 4 major tasks when documenting a crime scene

1)note taking 2)videography 3)photography 4)sketching. all 4 are necessary and non is an adequate substitute for another

exsanguination

when a person loses significant amount of blood dies by bleeding to death

serum

the fluid or liquid portion of the blood that does not clot

DNA is found...

the nuclei of white blood cells

viscosity

resistance to change of form or flow. blood is approximately 6x more viscous than water

angle of impact

90 degrees-the resulting blood stain will be circular in shape. less than 90 degrees- create an elliptical blood stain

mist pattern

bloodstain pattern resulting from blood reduced to a spray of localized micro drops as a result of the force applied. often with gunshot injuries

forensic pathologist

physicians specializing in the diagnosis of disease and subspecialize in the borderline area between law and medicine and determines the cause of death

in most US states medical examiners are required to be

forensic pathologist

forensic pathology

the specialty of medicine and investigating the causes of sudden and unexpected deaths

4 goals of death investigation

1) determine cause 2) determine manner 3) determine mechanism 4) determine time of death

cause of death

the disease or injury that initiated the lethal chain of events that led to death. underlying cause. injury trumps disease

mechanism of death

a biochemical or physiologic abnormality produced by the cause of death that is incompatible with life

manners of death

natural, accidental, homicidal, suicidal. NASH

rigor mortis

stiffening of muscles following death. usually seen about 4 hours after death. usually disappears 24 to 36 hours after death

livor mortis

discoloration of the body that occurs from settling of red blood cells. lividity becomes fixed(pressure will not blanch lividity) after about 12 hours. disappears about 36 hours after death

algor mortis

cooling of the body after death. 1.5 degrees celsius per hour for the first 8 hours. normal body temp is 37 degrees celsius. due to environmental condition- rough estimate only

incised wound

injury produced by a sharp instrument(knives, swords, axes) and characterized by lack of surface abrasion. produced by sharp objects

inframammary incision

customary technique in the US for autopsy's. T shaped incision. shoulder to shoulder down to the pubic bone

4 types of traumatic deaths

mechanical, thermal, chemical, electrical

mechanical trauma is subdivided into...

sharp force and blunt force trauma

blunt force trauma

a non penetrating injury that results from force applied to the body

sharp force trauma

injury to soft tissue or bone caused by a sharp edge or pointed weapon

lacerations

produced by blunt objects

lead snowstorm

diagnostic of a high speed projectile. around the missing tissue of a gun shot wound are white fragments of lead

blunt force trauma is dividing into

non firearm and firearm

fire arm trauma is divided into

low velocity and high velocity

penetrating gunshot wound

has an entrance wound and no exit wound

perforating gunshot wound

has an entrance wound and exit wound

contact or near contact wounds

touching or very close to the skin when fired. The effects of gas is seen on the wound-blackening of the skin + variable amounts of lacerations. will turn bright red

distant gunshot wounds

lack smoke and powder effects

abraded

a scraping type of wound

contusion

a bruise; bleeding beneath the surface of the skin.

hematoma

a blood tumor. contusions with more blood

asphyxia

the interruption of oxygenation of the brain

manual strangulation

use of hands to strangle someone

ligature

an object such as a belt, rope, or cord that is wrapped around the throat to cause asphyxia

diatoms

unicellular organism found in fresh and salt water. finding diatoms in bone marrow can confirm drowning

forensic anthropology

study of human biological function and variation, particularly skeletal biology applied to forensics

3 tasks of the forensic anthropologist

1) identifying the victim and providing a biological profile 2) a taphonomic assessment 3) providing data regarding the death event, including evidence of trauma at perimortem period

biological profile

provided by the forensic anthropologist. determines the age, sex, stature, ancestry, etc. of a dead body

taphonomic assessment

the assessment of the condition of the dead body in conjunction with the context in which it was found

perimortem

at the time of death

odontology

the scientific study of dental anatomy and biology of teeth

postmortem

an event or process that occurs after the time of death

antemortem

before death

taphonomic context

the immediate environment and surrounding where the body is found

diaphyses

bone growth centers that forms the shaft of a long bone. size is a common indicator of age in infants and children

deciduous dentition

20 baby teeth that will be replace by adult teeth

permanent dentition

32 adult teeth. 2.1.2.3

osteoporosis

a pathological loss of bone density and increase in risk of fracture

4 ways of observing bone density

1)macroscopically-v general 2)radiographic- x rays 3)bone densitometer assessment 4)microscopic-look at osteons

osteons

cellular structures that increase in number with age

pubic symphysis

one of the most reliable indicators of adult age. area on the pelvis where the right and left pelvis halves join in the front of the body. with age they turn more flattened and rimmed

sexual dimorphism

the average distance between shape and size between male and females. the skull and pelvis are the most sexually dimorphic skeletal areas

postcranial

below the skull. larger in males

stature

the overall height of an individual.

osteometry

the scientific measurement of the skeleton and of skeleton elements. forensic anthropologists are trained in this.

positive identification

identifiaction that is medically certain and accepted as such in in the court system. generally including identification by an expert using DNA, fingerprint, x-ray match etc.

what are the 3 levels of certainty when for identification of a body

1)lowest-possible 2)medium-probable 3)highest-certainty beyond a reasonable doubt-includes identification by DNA, X-ray match etc.

antemortem trauma

injury to a body that occurs during life. anthropologist can determine this by the presence of scars or callus at the site of fractures

perimortem trauma

occurring at or around the time of death

5 things t be included in the forensic anthropology report

1) chain of custody 2) taphonomic assessment 3) biological profile 4) identification characteristics and interpretation 5) description of trauma

entomology

the study of insects associated with a body. most useful in determining the time of death of a body

2 methods in estimating time elapsed since death using entomology

1) development of blow flies over time-few hours to several weeks. 2) successional colonization of the body by a sequence of carrion insects-any time after death

blow flies

flies that are often first to arrive at the body

successive colonization

process by which a body is colonized by a series of insects spaced out over time

carrion

decaying flesh of an animal

2 reasons blow flies are attracted to flesh

1) looking for a protein meal to allow their genitalia to develop 2) mainly mature females are attracted because they are looking for a suitable place to lay their eggs

life cycle of blow flies

1) first stage maggots-feed on liquid protein 2) second instar maggot 3) third instar maggot-frequently aggregates in large masses. 4) wandering stage-leaves the body in search of place to become a fly(usually only several feet)

4 things the 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

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

what can a forensic entomologist determine about a dead body

1) time elapsed since death 2) whether the body was moved or not 3) whether the body was revisited after death 4) indicating a wound but not state a wound site(this is the pathologists job)

bioaccumulate

the process of substances building up overtime in an organism. useful for entomologists to determine what drug was consumed. insects feed on flesh and consume the chemicals. cant determine amounts tho

importance of DNA in entomology

DNA of the host or dead body can be found in the stomachs of the insects feeding of off it. if body is moved and insects remain. identification is still possible with the insects

myasis

infestation of living humans or other vertebrate animals with dipteran larva

serology

involves the examination and analysis of body fluids and among those fluids, blood

presumptive test

a chemical test which by production of color or light indicates the presence of body fluid of forensic interest

confirmatory test

usually follows a presumptive test. used to confirm the results of preliminary analysis or presumptive tests

hemoglobin

the oxygen carrying substance in blood

false positive result

in a catalytic color test when testing for blood this is when you get a positive result from a substance other than blood

false negative result

in a catalytic color test this is when you get a negative result even when blood is present

catalytic color tests

used to identify blood from surfaces or stains. uses chemical oxidation of a chromogenic substance by an oxidizing agent catalyzed by the presence of blood

chromogenic substance

capable of generating a colored species

benzidine

a reagent that was once widely used in a presumptive test for blood. no longer used because it is a carcinogen

tetramethylbenzidine(TMB)

used in place of benzidine, presumptive test for blood.

hemastix

also used to replace benzidine. commercial test strip that can be used as a presumptive test for blood. initially yellow, if immediately change to green or blue-blood