Disease or injury that initiates the lethal chain of events that brought about a person’s death
Cause of death: immediate = just before death, intermediate = intervening steps, proximate = what started the whole process. This is usually determined by the post-mortem examination.
Things that are NOT causes of death
Cardiac & respiratory arrest, renal failure, asystole
The nonspecific, final common pathway by which the cause of death exerts its lethal effect
Mechanism of death
How the cause of death came about or the circumstances under which the person died
Manner of death: classified as natural, accident (unforeseeable event that lead to death), suicide, homicide (killed by another person regardless of intent) and undetermined (doesn’t fall in other categories because you don’t know all the circumstances).
What is it called when people die and blood pools at the lowest point in the body because the heart stops pumping?
What is responsible for the green discoloration and marbling seen in deceased patients?
Bacteria from the GI tract begin the putrefaction process, when they get out of the GI tract and into the blood vessels they give the marbled appearance.
4 classifications of blunt force injury
Abrasions (scrape of superficial skin layer at point of contact), contusions (hemorrhage into soft tissue from ruptured blood vessels, may be away from site of contact), lacerations (tissue tearing due to stretching, crushing, shearing of avulsing) and fractures
5 different types of blunt force abrasions
Scrapes, road rash, patterned, impact and binding abrasions
What do you know about a yellow bruise?
It is at least 18 hours old because the heme has broken down to hemiverdin, biliverdin and is now bilirubin.
What is this bruise?
It’s not a bruise it’s a Mongolian spot.
Key distinguishing point in blunt force laceration
Tissue bridging: blood vessels and nerves stretch across the lacerations.
3 types of sharp force injuries
Stabs, incisions and chop wounds
Stab wound that can mimic a bullet wound
Wounds from ice picks or screwdrivers
Stab wounds into what tissue leave the best evidence for the weapon used?
Where are you likely to see defense stab wounds?
What should you do if you are working in the ED and a patient expires after you tried to save him from multiple stab wounds?
Leave all chest tubes and procedures in place so the examiner knows what you did and what the offender did
Characteristics of suicide incisions?
Multiple superficial wounds: hesitation wounds.
Common causes of death from sharp wound injuries?
Hemorrhage, air embolism, airway obstruction from blood aspiration, pneumothorax, infection, arrhythmia, brain infarct.
What will tell you if a wound was inflicted before vs. after death?
Contusions only form when the person is still alive.
How do you tell the range of fire in a person killed by a gunshot wound?
Contact (muzzle touches body, everything that leaves gun enters body), Intermediate range (gunpowder stippling) and distant range.
How can you tell where a bullet entry vs. exit wound is?
The hole will be smooth and circular at the entry wound.
3 Types of asphyxia
Suffocation (environmental lack or displacement of O2, smothering of mouth and nose, choking from internal away obstruction, and external mechanical pressure the obstructs airway) strangulation (hanging blocks blood flow, ligature and manual) and chemical (CO, hydrogen cyanide and hydrogen sulfide).
Why do petechia appear when people are strangulated?
It only takes 4.4 pounds of pressure to occlude the jugular vein. This leaves the vertebral artery supplying blood with no return and capillaries burst.
How do you determine that someone died of asphyxia from drowning?
Their circumstances. The findings are the same in someone who died from drowning and someone who died from other forms of asphyxia and then was thrown into the water.