Forensics Flashcards
superfetation
the occurrence of a second conception during pregnancy, giving rise to embryos of different ages in the uterus
Justinian Code (550 AD)
- regulation of practice of medicine & surgery
- proof of competence by means of examinations
- limitations of numbers of physicians in towns
- penalties for malpractice
- status & function of the medical expert in legal proceedings
Grand challenges in forensic science & death investigation…
- Molecular photo-fitting…
- Chemical imaging, profiling and age estimation of finger marks…
- Advancing autopsy practice… minimally invasive techniques & probes
- Digital forensic imaging and service centres… “Big Data”
Locard’s Principle
When any two objects come into contact there is
always a transfer of material between them…
Forensic medicine
The branch of medicine dealing with the application of medical knowledge to establish facts in civil or criminal legal cases, such as an investigation into the cause and time of a suspicious death
Divisions of Forensic Medicine:
- Medical law, medical malpractice & medical negligence
- Clinical forensic medicine
- Forensic pathology: Thanatology, Traumatology, Forensic science
sourcess of law
Codification of the Law
Court decisions
formal law
statutory law
court proceedings
- Statement (Sworn statement / Affidavit / Expert report)
- Witness order / subpoena
- Pre-Trial Conference
- “Viva voce” evidence / testimony
- Taking the Oath / Solemn Declaration
- “Examination-in-Chief”
- “Cross-examination”
- “Re-examination”
types of death
Somatic
Irreversibly loses innate personality, unconscious, unable to be aware of (or to communicate with) their environment, and unable to appreciate any sensory stimuli or to initiate any voluntary movement
Cellular
Tissues and their constituent cells are dead – no metabolic activity, aerobic respiration
Brain death
Somatic death with circulatory and respiratory spontaneous function
Brainstem death
Need ventilator support because critical centres dead
agonal period
during which the dying process occurs, and in homicide cases, is often the interval between the time of fatal injury and death
indications of death
No pulse - auscultation / ECG Respiration cessation Eyes- Loss of corneal and light reflexes -Fixed unreactive pupils – mid-dilated position, +/- difference in dilatation -Retina – ‘trucking of blood’
PM Changes
Rigor mortis Hypostasis Temperature Supravital reactions Autolysis mummification putrefication adipocere
Putrefaction
Entomology Animal predation Resuscitation Embalming Undertakers fracture
lividity
refers to an unnatural color of the skin
Livor mortis starts in 20–30 minutes, but is usually not observable by the human eye until two hours after death
stages of death
pallor mortis algor mortis rigor mortis livor mortis putrefaction decomposition skeletonization
putrefaction
the process of decay or rotting in a body or other organic matter caused by the uncontrolled growth of innate (gut commensals) and pathogenic micro-organisms
- Initial decay (36 / 72 hrs – 1 week)
- Black putrefaction ( up to 1 month)
- Dry decay then skeletonization
Adipocere
a late-stage postmortem decomposition product consisting of a mixture of free fatty acids (FFAs) formed under favorable conditions due to the hydrolysis of triglycerides in adipose tissu
formation of adipocere - requires immersion in water, burial in moist environment
supravital reactions
False positive signs suggestive of life
12 – 15hrs post death
Mechanical excitability of muscle
Zsakos phenomenon – patella
Localised muscle bulge - biceps
Electrical excitability of muscles
Chemical stimulation of the iris
pm fluid loss Signs
Skin – dry
Corneas – clouded and dry – “tache noire”
Loss of eye-globe tension
Algor mortis
Body cools as metabolic activity ceases post death until it reaches that of the environment
8-12 hours skin
Henssge’s Nomogram
mathematic estimation of the PMI using body temperature, mass and utilises various corrective factors for naked and clothed bodies in still/moving air
Factors affecting hypostasis
Skin colour - less perceptible in dark skins
Quantity of blood in system - e.g. anaemia, haemorrhage
Length of time body lies in the same position
Absent on areas exposed to pressure
‘rule of thumb’ PMI estimate
Body feels warm and is flaccid (dead <3 hours)
Body feels warm and is stiff (dead 3-8 hours)
Body feels cold and is stiff (dead 8-36 hours)
Body feels cold and is flaccid (dead over 36 hours)
Nysten’s law
rigor mortis starts from Face – neck – trunk – upper limbs – lower limbs
factors affecting rigor mortis
Exercise
Age – develops and disappears faster in children than adults
Emaciated
Temperature – the higher the temp, the faster the development of rigor
Cadaveric spasm
rare form of muscular stiffening that occurs at the moment of death and persists into the period of rigor mortis
Casper’s Rule
“When there’s free access to air, a body decomposes twice as fast than if immersed in water and 8 times faster than if buried in earth”
mummification
Dry conditions - desiccation instead of putrefying
Dry and leathery and often brown in colour
Commonly occurs in warm and hot climates, such as in the desert, but if the micro-environment is dry enough, it can occur anywhere
Mummification of finger tips and noses etc. can often be seen in adult bodies at the same time as liquefactive decomposition
Insects (especially moths and beetles) can degrade mummified remains
entymology
Necrophagous species - Invertebrates that feed on the corpse itself
Predators and parasites of necrophagous species - do not feed directly on the corpse
Omnivorous species - Feed on everything
Adventive or opportunistic species - Insects that use corpse as shelter, nest
post mortem artefacts
Animal predation
Post mortem gas bubbling
Right ventricle – not air embolus
Leptomeningeal vessels - not cerebral air embolus
Post mortem blood clots
Artefacts caused by preparation of the body
Undertakers fracture
Embalming - injection sites , change in body colour
death scene
an entity which is created when the police enclose an area of interest in relation to an actual or suspected offence
Diatoms
algae, microscopic unicellular plants that can be found in saltwater, freshwater, soils and on damp surfaces. In a case of “common drowning”, water, containing diatoms, enters the lungs and then passes into the bloodstream where the diatoms are circulated around the body to all body organs
Forensic palynology
the study of pollen, spores and other acid-resistant microscopic plant bodies, including dinoflagellates, to prove or disprove a relationship among objects, people and places that pertain to both criminal and civil cases
Forensic engineering
the application of engineering principles to the investigation of failures or other performance problems of machines, structure, component or material
Anthropology
the study of the biological and cultural aspects of humans
Palynomorphs
Insect and plant remains, particularly micro-charcoal
Postmortem redistribution (PMR)
refers to the changes that occur in drug concentrations after death. It involves the redistribution of drugs into blood from solid organs such as the lungs, liver, and myocardium.
ballistics
Internal Ballistics
Looks at the striations and other marks made to a projectile as it passes through the barrel of a firearm, called rifling
External Ballistics
The study of flight and angle of shot patterns
Terminal Ballistics
The study of the effect of the projectile on or in the target. Wound analysis
Pyrolysis
the thermal degradation of biomass by heat in the absence of oxygen and results in the production of charcoal (solid), bio-oil (liquid), and fuel gases.
most common cause of myocardial rupture
recent myocardial infarction cardiac trauma endocarditis cardiac tumors aortic dissection
hypoxia classification
Histotoxic hypoxia Diminished capability to utilize oxygen Anaemic hypoxia Decreased oxygen carrying capacity Stagnant hypoxia Collapse or reduction of blood circulation Hypoxic hypoxia Diminished oxygen intake
mechanical asphyxia
Suffocation (cutting off the air supply)- Vitiated atmosphere, External airway
Internal airway- Choking (aspiration), Airway swelling or obstruction, airway compression
Neck compression (vascular/airway compression)- Hanging, Strangulation
Chest compression- Compression (traumatic) asphyxia, Postural (positional) asphyxia, Miscellaneous
classic sx of asphyxia
Petechial haemorrhages
Congestion and oedema
Cyanosis
Engorgement of the right heart and fluidity of the blood…
smothering and gagging
Smothering – indicates blockage of the external air passages, usually by a hand or soft fabric
Gagging - fabric or adhesive tape occludes the mouth to prevent speaking or shouting
‘Café coronary’
sudden and unexpected death occurring during a meal due to accidental occlusion of the airway by food
mechanisms of death for hanging
Airway obstruction- oxygen deprivation (hypoxic hypoxia) with carbon dioxide accumulation
Reduced arterial blood flow to brain (anaemic hypoxia)
Reduced venous return of the brain (stagnant hypoxia)
Vagal inhibition (neurogenic cardiac arrest)
Cervical spinal cord injury
Blood-field neck dissection
Layer by layer strip dissection of the anterior neck muscles, cartilage and bone
Specialised technique that is necessary to do in order to prevent misinterpretation of artefactual haemorrhages in the neck
hydrocutions
Death is attributed to cardiac arrest due to vagal inhibition, which results from stimulation of vagal nerve endings
the young swimmers and alcohol, high state of emotions or excitement or overeating prior to swimming may be the predisposing factor
The situation where blood vessels dilated by the heat contract suddenly, when cold water is applied to the skin, leading to cardiac arrest
Cold shock response
a series of cardio-respiratory responses caused by the sudden immersion of cold water
s/s of drowing
Wrinkled feet and hands
Cutis anserina- goose bumps, a temporary local change in the skin when it becomes rougher due to erection of little muscles
drowining categories
Drowning with recovery – casualty rescued from water and recovers with resuscitation
Secondary drowning – Casualty rescued from water but dies between 30minutes and several days later
Primary drowning – Casualty fell into water or other fluid and consequently died immediately or within minutes
Pseudo-or apparent drowning – Casualty was already dead when immersion took place
dry drowning
It is thought that the volume of liquid inhaled causes protracted laryngospasm resulting in a vaso-vagal mediated cardiac arrest
Specimens from the genital area
must be collected in the following
sequence
extemal anal area external genitalia , especially the fold between the labia majora and labia minora vagina, especially the posterior fornix extemal os of the cervix
statutes
Inquests Act 1959
Non-natural deaths
Registration of Births and Deaths Act 1992
Natural deaths & death certification
National Health Act 2003
Rendering of a death investigation service (FPS)
Ch 8: Autopsies & use of human tissue
Regulations on Forensic Pathology Services: Defn of Unnatural Death
Health Professions Act 1974
Deaths associated with medical treatment
statute
a written law passed by a legislative body
Undertaker’s fracture
artifact related to poor handling of the corpse characterized by subluxation of the lower cervical spine from tearing of the intervertebral disc at C6-C7 vertebral level. It occurs due to sudden fall of the head over occipital region.
non natural deaths
Physical or chemical influence
Action or omission amounting to negligence
Procedure related & anaesthetic death
Sudden / unexpected / unattended death
Health Professions Act 1974, Section 56
“The death of a person undergoing, or as a result of,
a procedure of a therapeutic, diagnostic or palliative nature
or of which any aspect of such a procedure has been a contributory cause,
shall not be deemed to be a death from natural causes
Traumatic and positional asphyxiation
Traumatic asphyxiation
external pressure to the chest resulting in asphyxiation
transportation injuries, collapsed buildings or mines
Positional asphyxiation
restriction of chest movement due to external pressure resulting from positioning
commotio cordis
ethal disruption of heart rhythm that occurs as a result of a blow to the area directly over the heart (the precordial region) at a critical time during the cycle of a heart beat
increased risk during: sports
pulmonary barotrauma / “blast lung” shows
haemorrhage oedema laceration contusions ALI (acute lung injury) ARDS (acute respiratory distress injury)
classification of Blast Overpressure (BOP) injuries: primary, secondary, tertiary and quaternary
Primary injuries are caused by the effect of transmitted blast waves on gas-containing structures
secondary injuries, by the impact of airborne debris
tertiary injury, by the transposition of the entire body because of blast wind or structural collapse
quaternary injuries, by all other forces
Primary medical cause of death or COD
The initial disease or injury that first set in and which eventually resulted in the demise of the person, even though it may have caused the person one or more intervening medical complications
Stab wound to the chest, ruptured appendix
Mechanism of death
The (patho-)physiological disturbance which ultimately results in death of a person and which follows on or arises secondary to the pMCOD
whipple procedure (pancreaticoduodenectomy
an operation to remove the head of the pancreas, the first part of the small intestine (duodenum), the gallbladder and the bile duc
ancillary investigations eg
Histology Molecular pathology – including DNA analysis Toxicology Ballistics Trace evidence analysis
contrecoup injury
occurs on the opposite side of the brain from where the impact occurred
Puppe’s Rule
if multiple gunshot or blunt force trauma wounds are present it is possible to establish the sequence of shots/hits. A fracture will stop when it hits another fracture
Duret haemorrhages
small linear areas of bleeding in the midbrain and upper pons of the brainstem. They are caused by a traumatic downward displacement of the brainstem
Diffuse axonal injury
Damage to axons of any aetiology which traumatic axonal injury (TAI) is but one of the examples. It is primarily a non-impact rotational acceleration-deceleration phenomenon, deformation by stretching probably being the most significant factor
most common pathological feature noted in TBI
Traumatic axonal injury (TAI)
damage to axons caused by trauma, which may vary from small foci of axons to more widespread brain damage
Sequela of brain injury
Cerebral swelling Raised intracranial pressure Hypoxic / ischaemic brain damage Infections Neurological sequelae Enlargement of the primary haemorrhage Traumatic aneurysm
Triticeous cartilage
a small ovoid structure belonging to the laryngeal skeleton. When calcified, it becomes visible on panoramic radiographs and be mistaken for a carotid artery calcification (CAC) associated with cerebrovascular accidents
Prinsloo and Gordon Haemorrhages
artefactual extravasation of blood into the anterior neck structures at autopsy, resembling traumatic bruises, and recommended a layered in-situ approach to the neck dissectio
Post mortem hypostatic haemorrhages (Tardieu spots)
intense lividity can be associated with small hemorrhages in the skin
Resuscitation related neck injuries
- CVP / IV insertion - SCM haemorrhage
- ETT – laryngeal mucosal haemorrhage and oedema
- Application of cricoid pressure
Erotic asphyxiation/ Sexual asphyxia
This type of sexual activity involves intentionally cutting off the air supply for you or your partner with choking, suffocating, and other acts
restraint asphyxia
when a person is restrained and left alone prone, such as in a police vehicle, and is unable to reposition himself or herself in order to breathe
Carotid sleeper
direction of force on neck aimed at compressing carotid aa
bar hold
force applied across front of neck compressing the irway
lightning-induced injuries- light component
uveitis, cystic macular oedema, macular
holes, Bilateral iridocyclitis, cataract with
posterior subcapsular damage
lightning-induced injuries - heat component
First-degree burns may follow the skin
creases. These marks may be centimetres
long and generally follow the long axis of the
body towards the ground.
smell of singeing or burning about the body
and clothing. The hair may be scorched or
singed.
lightning-induced injuries - electrical component
Lightning injury may cause abrupt cerebral
salt-wasting syndrome. Lightning injury may
even cause delayed-onset psychiatric and
cognitive symptoms.
lightning-induced injuries - barotrauma component
The primary targets for blast overpressure damage are the hollow organs, ear, lungs and GIT.
Free- radical-mediated oxidative stress may occur
and contribute to blast overpressure injury.
lighntning induced pneumo mediastinum
lightning strikes Rx
As a treatment, use fluid therapy and/or analgesia and anti-oxidants.
Focus on cardiovascular therapy, central nervous
system therapy, burn wound therapy, eye
therapy and ear therapy, and consult specialists
in these fields where necessary.
lightning strikes complications
haematological abnormalities
endocrine and sexual dysfunction.
psychological and neurocognitive dysfunction (memory disturbances, concentration
disturbances, cognitive dysfunction and problems with higher executive functioning
Injury mechanisms
ground curent side flash upward stream direct strike contact with obbject
Hide and die syndrome
occurs in the final stages of hypothermia. The afflicted will enter small, enclosed spaces, such as underneath beds or behind wardrobes. It is often associated with paradoxical undressing
High altitude illness
the current accepted clinical term for a group of disorders including acute mountain
sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE), which occur in travellers visiting high-altitude locations
law
a body of rules, governing human behaviour, prescribed by the society, applied by the courts and enforced by the executive”
medical law
refers to that body of rules of law relating to (a) the medical profession; (b) the relationship
between doctor or hospital on the one hand and patient on the other; (c) the relationship between the medical profession and other health care workers;
(d) the doctor and health care legislation
Causes of Trauma
physical
Mechanical Thermal Electrical Barotrauma Ionizing radiation Ultrasound
chemical cause of trauma
External contact Ingestion Inhalation Intravascular Rectal
Hypoxia / Anoxia
Histotoxic
Anaemic
Stagnant
Anoxic
Long QT syndrome (LQTS)
condition in which repolarization of the heart after a heartbeat is affected. It results in an increased risk of an irregular heartbeat which can result in fainting, drowning, seizures, or sudden death. These episodes can be triggered by exercise or stress
res ipsa loquitu
the principle that the mere occurrence of some types of accident is sufficient to imply negligence
Fimbriated hymens
characterized by redundant folds of hymenal tissue with scalloped rims that circumscribe the vaginal introitus
Monro-Kellie doctrine or hypothesis
the sum of volumes of brain, cerebrospinal fluid (CSF) and intracerebral blood is constant. An increase in one should cause a reciprocal decrease in either one or both of the remaining two
Types of Atelectasis
Resorptive Atelectasis Relaxation Atelectasis Adhesive Atelectasis Cicatricial Atelectasis Round Atelectasis.
skull fracture types
Depressed frcaturs Depressed vault fractures 2. Linear fractures Hair line - vault Basilar- skull base Diastatic (along suture)-> comminuted (multiple pieces) or hing door (one piece and simple) 3. Hinge fractures 4. Rung frcatures 5. “spiders web’ fecatures 6. “blow out’ frcatures
Tardieu spots
purple to black spots on the skin that can develop along with lividity, from the rupture of capillaries
Injuries seen in an MVA
Skull and facial fractures Brain and its coverings injured Cervical spine injuries Rib/ Sternal Heart Liver injures
Typical injury in PVA
- Beta rupture of the aorta
- Hypeflexion and hyperextions of the spine
- Traumatic axonal inury
- Cord damage
- SAH
- Blood in fourth ventricle
If a run over injury occurs
Disrupted skull Externalised brian Internal organs ruptured Pine fractures Chest compression- flail chest
How to assess if baby lived outside mom
- ‘flotation tst’ (hydrostatic test)
- If lung/piece of lung sinks in water, baby had not breathed suffieicnely to expand lung or mau
have been still born - Milk in stomach
- Stomach flotation test
- Umbilical cord remnant shrivelled/ shows inflammation of impending speeration
- Umbilical cord skin junction look for vital raction on microscopy
locus standi
the right or capacity to bring an action or to appear in a court
Saponification
process by which triglycerides are reacted with sodium or potassium hydroxide (lye) to produce glycerol and a fatty acid salt called “soap.”
Medical criminalistics
It includes the clinical examination of surviving victims and suspects, the inspection of the scene in suspicious deaths with subsequent performance of medico-legal autopsies, the assessment of (biological) traces and the reconstruction of criminal events under medical aspects
Pontomedullary rent
a primary injury to the brainstem that may occur in high-speed accidents
eg of necrophagus spp of insects
Calliphora vicina, Phormia regina, Protophormia terraenovae
predators and parasites of necrophagus spp
Silphidae (carrion beetles) and Staphylinidae (rove beetles)
Hymenoptera
omnivorous insects
ants, wasps, and some species of carrion beetles
opportunistic insects
springtails, centipedes and spiders.
Channelopathies
diseases caused by disturbed function of ion channel subunits or the proteins that regulate them. These diseases may be either congenital (often resulting from a mutation or mutations in the encoding genes) or acquired (often resulting from autoimmune attack on an ion channel)
